I’ve built quite a few french drains in residential settings, some lasting longer than others - I’ll share a few hard earned lessons here:
Soil migration is the number one failure mode. This is mentioned but perhaps a bit understated in the video.
To prevent soil migration you absolutely need commercial grade geotextile fabric wrapping the gravel and pipe.
You can buy pipe with much bigger and more numerous holes than the tiny slits depicted in the video. That also obviates the need to decide what orientation the holes should be.
Void space is the most critical factor when choosing gravel. You need a lot of space between the rocks to support fast drainage. Do not use playground pebbles or anything similar. Pay close attention to the type of aggregate you’re buying.
Calculate how much water you actually need to drain. You can use the “100 year flood” values for your locale to get an upper bound on rainfall, then multiple by drainage area. This is especially important if your roof is part of the watershed.
Sometimes there is insufficient gradient to move the water anywhere, ie the land is too flat. In this case you may be better off building a drywell, which is constructed very similarly.
Our first house was one a 1/2ac lot at the end (bottom -- this will become important later) of a cul-de-sac in a great semi-urban neighborhood in Cary, NC. We learned after repeated backyard flooding and near-incursion of storm water into our patio door that our street had been built on what had been the original stormwater collection pond for the larger neighborhood. The builder got permission from the city to move the pond to build our cul-de-sac, but that didn't stop our street from still being the lowest point in the neighborhood, where all surface water ran-off to, and our house was at the very lowest point.
Long story short, we ended up installing a french drain on two sides of our house, putting a drain at the end of our driveway to redirect water [from just running down our driveway to our house], having the front wall foundation rebuilt and jacked up because the footer had nearly completely eroded (1970s house), and still needed to add two 24" square drain boxes in the back yard (with buried 4" PVC draining into the creek at the back of the property) to remediate all this. It was also a tree-filled lot and the drain boxes would almost immediately clog with leaves during heavy rains, so I spent a lot of time out there in ankle to knee deep water with a rake to keep the drains clear.
This still wasn't enough! We got a so much surface run-off from our uphill neighbors that it looked like a sheet of rushing water across our backyard during heavy storms. We had a creek at the back of the property but were not allowed to mess with it because of Corps of Engineers easement regulations. At the end of the day, we finally solved our problems by getting an agreement from our neighbor to let us dig a surface water drain from the low point in their yard into the creek, and then we'd build a "temporary" (cf prior easement rules against permanent walls) berm along the property line to prevent surface water from coming into our yard at all. That "berm" was 76 bags of Qwikrete stacked three high and covered with grass clippings, yard waste & mulch. Technically we could have removed it if the city had inspected, but it was very much a cement wall.
We have never since, and never will, build or purchase a house at the bottom of a hill.
20+ years ago, I had moved into a newly built home. And the first serious rain we got, I had water come into the living room (flooded the porch and seeped under the door). There was no insurance coverage since it was "surface water" and thus excluded. So I had to use a shop-vac and rent a couple of blowers to dry it out.
There was a ditch out back but it obviously wasn't deep enough. I did the math and ended up with an astounding amount of water flowing by (something like 20,000 gallons per minute[0]) and complained to the builder about it. They sent a couple of guys out there who installed two 4" corrugated drainage pipes and said it was good enough.
When the next big rain happened, where those pipes emptied out there was a 3 foot tall fountain of water from the pressure. It was an amateur Bellagio, lol. The yard still flooded but luckily didn't come into the house again.
Since then, the landscaping came in throughout the neighborhood which controlled the runoff. But it taught me a lot of respect for getting slopes & drains right - Always use a larger pipe than you think you'll need.
[0] The formula seems to be: V = 0.408 × Q/(D^2) where V is velocity in feet-per-second, Q is the flow rate in gallons-per-minute, and D is the diameter of the pipe in inches. I estimated the diameter based on the land profile that was underwater, and timed the velocity by following twigs/leaves floating by.
You probably got a bit higher number than the true one, because water flows faster the farther it is from the floor/wall, and leaves float so they move like the fastest water, not the average water.
I checked my policy and they use the "surface water" term. So it's probably something that varies by company and perhaps region.
To get a flood policy you would have to speak to a broker about whether you qualify for the National Flood Insurance Program. They won't issue a policy to you directly.
I've visited Lloyd's Building on a building tour once, and seeing the scale and sheer floors of actuaries with PhDs in god knows what domain made me a firm believer in the real life prowess of the insurance industry. I honestly don't think consumer insurance is worthwhile, but commercial definitely if you have an equally capable team of actuaries to run the numbers and they stack up to cover the risks involved.
Sure but all these people are there to ensure the insurance will get ahead, not to help the customers.
One of my friend works in reinsurance and his favourite joke is that every time the insurance company pays a claim, someone is getting fired. Obviously a joke but it seems to paint a fairly accurate picture of how the business is run.
A lot of insurance companies have caps on profit, either as part of their structure or by regulation. Often the cap is structured as a percentage above covered losses, so administrative costs, including executive salary expense are effectively limited. In health insurance, this can lead to cost inflation, but I haven't really seen that in home and auto --- the market of service providers is so different.
Certainly, they're in business to make money, and helping customers is just part of the process, not their goal.
But --- it's in the customers' interest for the company to be accurate about accepting and denying claims. If the company accepts claims that should be denied, that means higher premiums. If the company denies claims that should have been paid, that may result in the company having to pay those claims after appeal/lawsuit and possibly with penalties; penalties get paid by the pooled insureds one way or another.
Insurance fills a need and is not just an evil company doing evil. Most insurance covers risks of loss that the insured would be unable or unwilling or at least unhappy to cover themselves. For most homeowners, if their house burns down, they would be unable to rebuild without insurance, unless there was clear liability from a person or company with big pockets.
As I understand, a lot of property and casualty insurance companies are structed as "mutuals" (not sure the exact term). And, most of the annual profit is refunded to customers. They are basically run as non-profits.
Technically true, but the people in charge are not the customers. The people in charge(C-Suite) have zero incentive to ever refund any annual profit. They have all the incentives in the world to ensure their compensation just happens to suck up any and all annual profits. Who is going to stop them?
Vanguard(the brokerage) is structured the same way pretty much, except it's the various mutual funds(like VTSAX/VTI) that own the larger corporation. So far the infection of c-suite salaries continually growing larger and larger hasn't gotten to Vanguard yet, but they are now a few CEO's removed from the original founder(Jack Bogle), so it's probably about time that shift starts to happen.
If what you say is true, why did they return any money at all? They could easily pay that to C-suite and senior execs in huge bonuses.
Also, to clarify, the correct term is "mutual insurance", which Wiki describes as:
> A mutual insurance company is an insurance company owned entirely by its policyholders. It is a form of consumers' co-operative. Any profits earned by a mutual insurance company are either retained within the company or rebated to policyholders in the form of dividend distributions or reduced future premiums.
From what I've observed, if the insurance company uses a mascot of any kind, you will have difficulties in getting them to pay a claim.
This is consumer insurance, so your typical auto, home, renter's, etc. policies. If you need commercial or E&O coverage, ask your broker to check them against the AM Best rating list.
I'm going to say that the vast majority of homeowners are not paranoid enough when it comes to buying their home. It is a huge investment and comes with very high transaction costs yet most people seem to make the decision based solely on superficial aesthetics.
What would you recommend noobs do, when buying a house? I guess hiring an expert would be the recommended approach, but all “experts” I have seen were all almost as superficial as I was - one literally assessed the wrong house. I’d pay good money for a good one, but it’s hard to find.
Find an aggressive home inspector that isn't associated with your realtor, preferably one with general contractor experience and someone who is older. Like it or not, older folks have seen more things go wrong in more ways and can spot problems that younger folks might not be familiar with.
I have certification of an inspector with various home things… Flooring, roofing, general home inspection.. no one wants to pay what it’s worth so I don’t practice that, it’s just fun for learning about the building trades
Further - if you never have a problem the value of the inspection is zero. If you do have a problem the value of an inspection after the problem has occurred is minimal. The value of an inspection that prevents a problem is something - but how to quantify that is difficult.
Depending where you live local/state/fed government will keep maps.
Topographic maps, flood risk maps, wildfire risk maps, maps of services nearby (substations, transformer locations, storm drains etc), easements, special planning/protection zones, surrounding area zoning etc.
These should all inform your decision. I've vetoed houses because they back onto nature/wildlife reserves, are too near substations, are in flood risk areas etc
I had a structural engineer come and look at a house I was thinking of buying. It cost me $500. I didn't buy the house, and that $500 was some of the best money I've spent.
Selling a house in Denmark requires the seller to acquire a “condition report” from a certified inspector. The report is valid for 6 months and costs around $1000. This also ties into the optional “owner transfer insurance” which covers serious defects / building code violations undetectable by the inspectors. The insurance lasts 5 years and costs $2000-$5000
In the US afaict inspections are a plus but not required for sellers to provide. Lots of people were waiving their right to inspection in order to make their offers on houses more attractive to buyers. Kind of a stupid thing to do, but people had low interest rates and were desperate to buy
The same way you hire a company for any service, start by searching for local structural/construction engineering firms and then call a few and ask if they’ll do an inspection on a residence.
If you personally know any architects or general contractors in the residential market, they should be able to recommend someone.
1895 house in Oakland with a soft story condition and a dining room that was cantilevered out over the aisle. It was listed for something like $850k in around 2018, so kind of cheap! But correcting the soft story and the rest of the framing would have been astronomically expensive. He guessed something like 400-500k, and now having experienced home renovations, I am fairly certain he was in the ballpark.
>I've vetoed houses because they back onto nature/wildlife reserves
Why is this a bad thing? To a naive person, it might seem like a good thing, because you get to look out into a forest rather than someone else's yard.
Essentially because nobody was allowed to trim/maintain the trees due to it being a natural habitat. It's nice to look at but when a 60m tree falls in a storm and wipes out your house it's not great. The reserve was also on the north side of the property and down here in the southern hemisphere that means that every year as the trees grow your house gets more and more shade with accompanying maintenance issues.
I should add that people may weigh that up and be happy to live there, but people should be aware of the risk/benefits before they buy. Natural light/property orientation and shading is a major issue that most people forget about.
Here in Western Australia there are online floodplain maps which show the extent of a 100-year event. Very usful when you see somewhere nice but wonder why the house and outbuildings are all crammed in the front quarter of the plot...
get a Chinese feng-shui expert; cheaper than pros and reap benefit of thousands of years of real estate wisdom. /s but not really /s lol there are some methods in it's vast amount of madness
Generally speaking, if inspectors did their jobs well, almost nobody would ever buy a house, due to the prevalence of existing issues and the cost of remediation. I've found that there is a duality of thought among homebuyers, where most want a "perfect" condition house, but also don't want to pay for a perfect condition house. At the same time, home sellers also don't want to pay any more than they absolutely must in order to sell the house, so you end up with inspectors as these not-entirely-impartial middle-men whose job is mostly to CYA while not identifying too many problems that could create a reputation for them that might limit future realtors & home sellers from using them.
It's all pretty silly, really, especially considering the hottest markets, where you either want a house or you don't, and if you you'll probably pay top dollar with no contingencies and possibly not even your own inspection... since the seller knows if you don't buy it someone else is in line right behind you. Most of the time, houses sold this way aren't in significantly worse shape than those that are fully inspected and repairs made before the transaction.
Overall, this has led me to believe that, in most cases, pre-sale inspections don't really benefit anyone, especially since it's so difficult for buyers to seek E&O recourse/damages against either an inspector or seller after the sale closes.
I think it depends on who is paying the inspector. When we bought our house, the realtor we were working with connected us with her best and most rigorous inspector. He found fifty pages worth of stuff that was wrong, but most of them were fairly minor.
We took that list back to the sellers (who were then legally required to provide a copy of that report to other future buyers), and we simply waived the little stuff. We wanted them to fix the big stuff. They didn’t want to do that, so they came down on the price by a considerable amount. He saved us tens of thousands of dollars.
Now, given the problems we’ve had since then which the inspector didn’t identify, we would have paid back more than what he saved us — Except for insurance coverage. USAA is really good about paying out on claims, when many other insurance companies would weasel out.
We love this house, we love this neighborhood. If we had to do it over again, I think we would have pressed harder to get even the minor problems fixed or to get the seller to come down even further on price. But I think we probably would have still bought this house.
I don’t blame the inspector for anything he missed. Most of those problems were well disguised, until such time as there was an actual catastrophic failure. He couldn’t have known. If I knew his name and contact details, I would recommend him to future buyers in the Austin area.
One of the prior houses I lived at had so much flooding and water leakage problems from poor construction (prior additions that weren't strictly legal) that lead to carpet and padding having to be removed from concrete floored rooms and eventually mold problems, that when I bought a house a few years after we'd ran away from that disaster of a house we made absolutely sure to my at the high point of the (new) neighborhood so we weren't in the drainage path for anyone.
It's particularly demoralizing to see the scope of the problem when it's all that water flooding your property and know there's nothing you can do in the short term, and even the long term is just trying different things and hoping they work, knowing that it will probably take a few tries.
Perhaps the balcony over your front door is not properly constructed and is not properly shedding rain, so one day during a torrential thunderstorm you suddenly have a flood coming in OVER your front door.
Perhaps your water heater pan is not draining correctly, and one day you have a catastrophic containment failure in your water heater, causing an interior flood.
Perhaps you change the toilet in an upstairs bathroom, and the new modern toilet is not providing enough water per flush to make the long run of the upstairs plumbing. So, it clogs up over time, then one day it backs up while you’re taking a shower, and you’re standing in multiple inches of grey water. Then the water does slowly drain, but you don’t notice that the pipe has cracked above the clog and it’s actually flooding into the room below, through the light fixture.
Perhaps the main schedule 40 PVC pipe from the water main at the street slowly develops a crack, due to the roots of a tree nearby, and one day you discover that the water pressure in your house is really low and that you have flooded the whole street.
Mine were incorrect drainage outside, causing water to pool high enough inthe back yard that it came through the slider into the converted garage, soaking the pad and carpet there (in a few different locations actually), and the much worse one where a room was build off the same garage onto a concrete pad that was laid, but one of the walls was build on top of a covered deck that was build off the garage on one side, which had water run down it, hid the deck, then immediately go under the wall to the concrete pad meaning even moderate rains that didn't result in outside flooding would result in that room's pad and carpet getting wet and needing to be entirely removed, and the wall ripped out and rebuilt as it eventually was overtaken by mold. A large chunk of the house needed to be blocked off, industrial fans installed to dry it out, and then professionally redone.
Building codes exist for reasons. Sometimes they seem frivolous, but often they're there for a damn good reason.
I've ruled out several properties in my current homebuying search for this exact reason. Having lived next to the neighborhood collection pond once before (a rental thankfully), I'm extra paranoid about stormwater and drainage now.
I've seen a number of homes in my area where the builder received special permission to build right where the drainage needs to go. Some were beautiful and I was tempted to give it a shot, but your story reminds me that I need to trust my gut on this issue and head for high ground.
I have almost exactly the inverse situation. We are at the end of a cul de sac that is capable of efficiently draining water away and out of the neighborhood. But in roughly the spot where your drainage creek is, there's a large strip mall parking lot (across the street from our backyard). We don't get a lot of rain in annual total, but when it does rain heavily a flash flood comes into our backyard and must cross our side/front yard to drain into the cul de sac.
The previous homeowner put in a DIY french drain, but either he didn't do it right, or it's too flat, or it's too small, or it is clogged. We instead get surface water flow and erosion along the same path where the french drain runs.
(It doesn't help that when our neighbors got sand delivered for an above ground pool bed, the delivery truck dumped the entire pile of sand ON TOP OF the river rock exit basin for our french drain. The sand was later removed/used but I was still upset; unfortunately it was my brother in law who ordered the sand. Since the drain is above it I don't think it went in the drain, but maybe this rock basin was supposed to be a dry well.)
I am thinking of building something like your concrete berm along my back fence line, possibly modifying the french drain to just transfer the water from the far side of the berm to the exit over the cul de sac rather than trying to absorb it from the ground.
Sorry to hear of your troubles. We live in Holly Springs, NC not far from Cary. When our builder was showing us land/lots that were available at the time they only had lots that had driveways that would pitch towards the homes (in other words the road was higher than the house, not by much maybe 2-3 feet or so.) Of course developers and realtors always assure you it won’t be a problem - I was not reassured and so we passed on these lots. A few months later a lot became available that was well above street level. We’ve been here 10 years and never had an issue through heavy rains and even a couple of hurricanes. But we’ve met the neighbors who bought those properties with the driveway pitching towards their homes and they complain about having water coming into their garages whenever we get heavy downpours. If you’re going to live somewhere long enough that may experience heavy rainfall, it’s best to be well above the low end of the neighborhood/street.
I live at the bottom of a valley, but luckily in a tiny house on a concrete pad, so I have no basement and I'm raised up two feet off the ground. That works pretty well for the house, but the driveway and yard still floods. So I dug a "pond" and small ditch things to channel water to it. You can't really tell where it is because I let my yard grow wild, but when it rains hard the water fills it up, and it evaporates/drains naturally over a couple days.
The ditch actually speeds up the water drainage. I dug the ditches to divert the water around the property line, so the surface area of ditch in total is large, even though you can't really see it and it doesn't get in the way. I figure at least a quarter of the water drains through the ditch before it gets to the pond. This is probably helped by the fact that the soil is very rocky.
Not sure you watched the whole video, he shows how soil migration causes failure (7:30), links to another video that covers that in-depth and discusses how geotextile isn't enough for things like damns (10:15). He also mentions that you can get pipe with holes all the way around (5:58).
> You can use the “100 year flood” values for your locale to get an upper bound on rainfall
I wonder, does climate change also affect those calculations, with the need to adjust those bounds upwards? I remember the (technical) term "100 year flood" getting lots of ridicule in the last years because we already got multiple "100 year floods" in the range of a decade.
Faster than climate change is development. The addition of impermeable surfaces like parking lots and buildings upstream causes more water to get to you.
Development happens faster than the flood maps get redrawn.
I wonder how well USA state agencies are doing in their efforts to map sea level rise, flooding, etc. and if they take into account development. I know a lot of work is being done in Virginia to address sea level rise, flooding in poor areas, etc. But because I live in a rural part of the state, I can't assess for development since it's not ubiquitous.
FWIW "100 year flood" refers to the flooding that is expected to occur in that specific area on average once every hundred years, not an event that will happen only once over the whole country once per hundred years. So regardless of climate change it makes a lot of sense to be seeing many hundred year floods since mass media has us caring about many areas in parallel, not just the specific area we live.
Also, as people have a life expectancy in the order of 100 years (75 perhaps?), there is a pretty good chance you will experience a 1:100 year event at some point in your life. Also a lot of infrastructure is built for 50-100 year life (or is still used after 100 years, even though it was designed for less).
The 1:100 year safety level should thus be considered a bare minimum for high impact events. In the Netherlands water infrastructure is designed to withstand the 1:10.000 year storm for catastrophic events, and e.g. 1:1.000 year storm for high impact events.
But even with higher safety standards, it is key to design not only for the current climate, but for the future climate over the design life of whatever you are building. Extrapolating 1:10.000 year events from 30 years of observations might seem sketchy already, but with all the uncertainties in climate change predictions is a bit of a stretch.
There's a pretty good chance you'll experience any given 1:100 year event. You're basically guaranteed to experience quite a lot of 1:100 year events, since there are so many options.
This is a misleading definition as it makes people believe that if there is a 100-year flood this year, that equal or worse flooding will not happen next year.
Long term observed water levels are fed into a model with normal distribution, and a 100-year flood is then defined as 99-th percentile of the model. This means that there's a 1% chance of a 100-year flooding each year.
Global warming and climate change have an effect that there's a lot more water vapour in air. Same air mass can deliver more rainfall on a given territory, pushing observed water levels into higher extremes, meaning what used to be 100-year flood is now 25 (4% yearly chance), 10 (10% yearly chance) or even 5-year (20% yearly chance) flood.
Yeah, that is another issue with the way the media frames things and commonly invokes "100 year flood". In my comment, "on average" is doing a lot of work for those not decently versed in probability.
Short answer yes, but as another comment suggested, development changes adding hard surfaces in new places in the neighborhood also rapidly change those calcs.
the 100 year flood is basically a mathematical concept - its about the long term average recurrence interval - the probability that the given event will be equaled or exceeded in a given year. The "100 year flood" has a 1% probability to happen in a given year, based on historical data and a normal probability distribution (which is what we see in nature).
I have to admit I have a degree in structural engineering and bashed my head trying to understand various bits hydrology for some time some years ago, and still occasionally dabble in it when I'm required to (although I leave it up to more competent hydrology experts 99% of the time).
Depending on how deep it is a drywell can be an EPA regulated thing in the US. This is because it can be a bad idea to sink surface water directly into the aquifer - naturally it would be filtered by the overlying soils, if it goes in directly then any surface contamination is washed directly into a reserve of drinking water.
But, I'm far from an expert so I can't give any advice as to when one would need registration etc.
The video also mentions that sometimes the geo textile fabric is not enough since it too can get clogged, though this seems important in dams and not so in simpler projects
The drain pipe is at the bottom of the drainage excavation. On top of the pipe is 3/4 aggragate, and on top of the aggregate is geotextile. Soil is filled in over the geotextile. There is no clogging risk in this design. Any soil particles that make their way to the pipe are carried away.
Yeah, I saw that video and many others long before it was posted here. I stand by my comment, which is based on experience and reviewing the work of professional drainage installers on YouTube.
No one is doing soil tests for these unless they are installing huge critical commercial infrastructure.
Any advice for homeowners living in a high water table area besides "move"?
We were a bit naive buying our new construction home. It's the only home on the street with a basement due to the high water table. One year after purchasing, Hurricane Ida hit and we had water up to the door handles in our basement. Our primary sump pump runs constantly for 18 minutes then off for 18 minutes 24/7. We have a backup pump on the other side of the basement connected via the perimeter drain, and a liberty water backup pump. The only addition since Ida is a whole house generator and superior window wells.
During Ida, the street was flooded, the drainage systems were backed up, and there was no where to pump the water to.
Unfortunately, you can't "drain" into saturated soil. At that point you're building a boat more than a house: keeping water out on all sides.
I'm assuming it's a fully-enclosed basement? I.e. no walk-out side?
The best you can likely do is waterproofing the basement walls + pumping out from inside or an inside-perimeter drain. But that's only racing pump_out_flow > seep_in_flow.
And that's a bad game to be in, because water under pressure (which it will be a story below ground) finds a way.
I'd make the basement flood tolerant (limit mold-hosting materials and places water can be trapped) + pump it out quickly after it floods + buy a dehumidifier, and accept it's going to happen.
As far as I can tell inside waterproofing is a bad idea, it leaves your foundation soaking wet, excess humidity indoors, and as you point out it doesn't alleviate the pressure from outside. Waterproofing the exterior, french drains deeper than the footings (all sides), and sump pumps... That should keep things dry but it's quite a process.
Foundations being wet aren't a huge deal. Exterior is recommended over interior because it's easier to ensure no gaps. But it does involve substantial excavation.
French drains around the perimeter help, but you're literally fighting water from all directions... including directly underneath.
Have a perimeter French drain but a crack in the slab? Enjoy watching water bubble up from that crack once things get saturated.
Yeah it's not a cheap approach but unless the water is coming in really fast it'll get the basement really dry. Key to have the drain and pump well below the footings otherwise yes the water will just be under the slab.
The issue with drain/pump solution is that at that point you're doing hydrological engineering.
There isn't a "perimeter" per se, because water is literally coming from depth (in most locals / soil types).
So drain/pump just creates drier 3d soil areas. Whether that's enough to attract all the surrounding water (at a high enough rate) that would otherwise be infiltrating depends on soil permeability (e.g. sandy or clay?).
A lot of the "handyman"-type "dry basement" shops have no idea about any of this, toss a generic solution in there, and then blame the gods if it doesn't work (and they've billed for time-consuming and expensive excavation).
Ah true. I live in a hilly region so the water issues tend to be rain water moving down hill (which is really mostly laterally). In that situation the exterior drain solution works well, totally dry basement. I don't know how common it is for water in a populated area to be coming from directly below but in that situation maybe it's a good place not to have a basement.
Yup we have a dehumidifier running constantly that drains into the sump pit. The basement still has a basement smell even though it's all brand new drywall, fresh paint, etc. The dehumidifier keeps the humidity around 40%, otherwise it would be approaching 75-80%
Do you know if there's an impermeable barrier on the interior walls? And what foundation material behind the drywall?
It gets dicey applying internal barriers, because one needs to be thoughtful about making sure there's a place for water to go when it's actually too much (you don't want an internal barrier to be a dam holding back all the pressure), but it can be an option.
They sell them in membrane form or paint-type form.
Up here in Alaska, I tend to get a little water seeping into my basement at the cove joint (walls are ICF) after heavy rain and/or the spring thaw. Now, the floor in the basement is concrete, and whoever built the house had the baseboards and drywall over an inch off the floor, so towels and a de-humidifier tend to dry it out and nothing gets ruined since we learned to keep things off the floor. Trying to think of a way to address it without digging around the foundation to put in more/better drainage. Maybe just add a sump pump... I know, kind of a band-aid solution.
Are you in the construction or related business? I've had to learn some of these things the hard way myself. I learned I was outclassed and so I hired a geotechnical engineer to design my now-deployed drainage. (french drain plus site drainage)
I wonder what building codes require, ie from engineering and inspection POV, like can the things you mention even be built today? If so isn't this a failure of the planning departments?
> To prevent soil migration you absolutely need commercial grade geotextile fabric wrapping the gravel and pipe.
The article seems to be quite clear that, for critical applications, one should not use geotextile fabric at all — instead one should use (appropriately selected!) sand.
>Calculate how much water you actually need to drain. You can use the “100 year flood” values for your locale to get an upper bound on rainfall, then multiple by drainage area
Yes, "should." I've found that should happen and did happen are two very different things when it comes to a lot of homes.
Incidentally, our roof had gutters/drainage originally. We put in our own french drain after about 8000 hours of research, and decided to re-route the roof drainage to right above the new french drain (separate pipes) because the roof drainage broke at some unknown point and was dumping water around our foundation piers (yay...). Well, our roofers came and installed gutter guards after all this, which caused the gutters to shed 60% of the water into the drainage area because of the way they're angled. If we hadn't put in a french drain, it'd be a real problem, but as it is now, it's a mild annoyance that I keep telling myself I'll fix.
I have used French drains on buildings where I didn't want to install and maintain gutters. The roof shed straight into a gravel path (no soil coverage) around the building that had perforated pipe leading to a dry well. Worked perfectly. In one case the pipe had to be very shallow so I used crusher-run (404) aggregate to form better support around the pipe at the surface. Again, worked perfectly. You really have to watch the details and plan things out meticulously for the given situation.
I had absolutely no idea this was named after an American!
My parents home is on a mountainside. All the rainwater collects higher up the mountain and then moves down the mountain where their house is in the way. The soil is thin, mostly clay, and you hit bed rock very quickly. When it rained, water would have little place to go under the soil and would surge up under pressure in areas to the surface. One of those areas was that house.
They purchased the house new and the builder neglected to consider this water reality, so for the first couple years the basement would flood from the bottom, then later water would come rushing into the basement windows.
They spent a small fortune with heavy equipment digging out underground trenches in this rocky environment and laying french drains around the perimeter of the house, and then also in a long diagonal in front of the house as a sort of catchment. The collected water was routed underground and around the house to an exit further down the mountain.
This stopped all the flooding immediately, so much so that my parents finished the basement and turned it into a massive master suite where it stayed dry for decades.
A handful of years ago, my father passed on, and early the next year when the rains started, the flooding starting up again. My mother, absolutely distraught had me come out, and the water had destroyed flooring, drywall, window treatments, furniture, books -- it looked like the aftermath of a hurricane. During one rain I watched waterfalls come in the windows...clearly something had gone wrong with the drainage system.
We had engineers come out, concerned that the water had cracked and penetrated the foundation, but no, it turns out the French drains had failed in someway. Another small fortune, they were dug up, replaced, redone, and now....no flooding again.
This is a great video that may have explained exactly what happened.
> We had engineers come out, concerned that the water had cracked and penetrated the foundation, but no, it turns out the French drains had failed in someway. Another small fortune, they were dug up, replaced, redone, and now....no flooding again.
Generally speaking you want some kind of inspection/clean-out port so you can snake a camera through the system to see what's going on:
A simple sump (basically a hole in your basement floor), and sump pump, can help identify it before it reaches your basement floor. IIRC, this is also covered (albeit briefly) in the video.
High water pressure at the basement walls can result in intrusion without ground water below the floor being a problem. I have no sump/drain in my basement as it never floods because it sits on well draining soil. A neighbor's driveway directs water toward my block foundation and, with heavy rains, the localized pressure in the saturated soil along the wall would produce a jet of water coming out of a hole in the mortar. I resolved it by digging a swale that diverted that excess water around the foundation. It is much easier to maintain than a French drain that would silt up rapidly given my soil.
I was thinking more, check for buildup of water upstream of the barrier as an early indication of blockage or restriction. If the gravel or whatever is clogged, you'll see high water behind it.
First time I hear about Nebula, and seemingly the website doesn't want to tell me what it is. Looks like a YouTube alternative?
The FAQ mentions that it's owned by CuriosityStream, which I've heard about before, founded by John Hendricks who also founded the TV channel/network Discovery (now Warner Bros something something).
As far as I've seen, CuriosityStream is mainly about "popular-science" stuff and over-dramatized American "documentaries", is Nebula something in the same vein? Would be weird to see Grady over there if so.
Nebula is really nothing like CS. It's a video streaming service which many online creators (most already on YouTube) post. Currently a lot of Video Essays. Many creators choose to publish simultaneously on YT and Nebula, but Nebula has no ads and they can rely on sane applications of fair use policy.
Creators often also post exclusives or early releases.
Curiosity Stream has a minority stake. The subscriptions used to have a significant discount if you bundled them, but starting last December, Nebula decided they wanted to be more premium. https://blog.nebula.tv/unbundle/
That is rather unfortunate - if you were so inclined, you could contact their helpdesk <help@nebula.tv> as mentioned at the bottom of that FAQ page and tell them about your experience
Regrettably, I have been following Nebula from its early years, so I don't have the elevator pitch to offer other than "videos on YouTube are dictated by YouTube, videos on Nebula are dictated by their creators" plus the obvious ad-free experience. This is some inside baseball from the channel that I recall introduced me to Nebula https://www.youtube.com/watch?v=Alqt6RCEWdM
As for your popular science concern, in general my answer is "no," it's not marketing drivel designed to inject ads into your eyeballs. However, since it is just a video platform (err, and also classes, news, and podcasts) the content quality is ALL OVER the place. That was actually why I didn't subscribe for such a long time - it was like those "web 3" video platforms - only fringe stuff was on it, so it wasn't worth my time or dollars. Since then, they have gotten a lot more content that I value so I pay by the year now
Merely as a frame of reference, here are some of the channels that I follow
One thing a of the makers push is that they can make videos on controversal subjects without fear of being demonetized like they would on youtube. This can be things like the current middle east conflict or some more adult channels. But they are not going for the more radical "banned by youtube" makers.
Thanks so much for the recommendations, those do seem like something I'd enjoy!
It also highlights another aspect of a non-adtech owned platform: I can watch videos without fear that they're going to poison my feed and cause some topic that I was merely curious about to suddenly fill my homepage
I discovered French drains while trying to dig a hole for a fruit tree a while back. The land was on a hill and about 30cm down I hit this huge pile of dirty gravel. Ok, so maybe someone filled that spot with gravel. Sunk another hole a bit farther down. More gravel, etc. It took me longer than i'd like to admit to figure it out.
Turns out it was the main drainage for the whole neighborhood. Heh. Moved my tree to the side and it thrived on all that lovely water.
Tree should be far away from the drain line. The roots will eventually grow into the pipe. Tree roots are incredible at finding water sources. Even a drop-at-a-time drip from a water pipe will be completely root wrapped in a few years.
Funny, that happened to a neighbor. There was this teeny crack in a pipe, and a tree root had squeezed into it then ballooned into this alien creature that blocked the drain in an attempt to suck out the water.
Fertilizer would be welcome, pesticides less so. Fortunately, one doesn't really need pesticides on lawns, particularly if one doesn't have a dislike of non-grass species (like clover, which helps with fertilizing anyway).
That might depend on where you are. In my part of the US, fertilizer runoff is causing very serious problems. This is mostly from farms, of course, but domestic lawn care is a major source as well.
The push around here isn't to get people to stop using it entirely, but to follow proper practices that minimize the runoff.
I live in a very high tick area in upstate NY, and I've never seen this. I certainly don't do it and have had no problems. Now, if I wander just off the lawn into the woods, I better be wearing my permethrin clothes.
As someone whos been thinking quite a bit about land restoration I cringed a bit when watching the video about the Henry French's philosophy.
There's a more encompassing worldview perspective that should be taken where rather in terms of thinking about 'superfluous water' there should be an inquiry around what relation one wants with water - where are the areas you want to perhaps concentrate water (e.g. at a pond/rainwater harvesting) and dryness (e.g. where you have a human settlement structure), and how one can 'slow, spread, sink' water to have a healthier relationship to the greater watershed and relationship to atmospheric water vapor.
We have to also think about how waters being removed from land. Is it being removed so quickly that we end up with low rivers and risk of saltwater intrusion during drought conditions [0]? Is water drainage not getting buffered by say, growing vegetation?
My argument isn't against French drains outright, but whether we're thinking more broadly about the impact of human relations with water.
I get where you are coming from but I feel when you look at the greater picture this concern would be completely mooted. The fact is that most unwanted water happens due to construction, with things like streets, parking lots, driveways, etc creating impermeable surfaces that force the water to build up and flow downhill and into foundations when, if things had been truly left untouched, there would have been no problem at all to begin with.
Surely that's a mitigating factor that makes it much more acceptable to geoengineer water removal?
I think I'm trying to advocate for appropriate geoengineering, thinking about not just water removal but also how water should be removed (how quickly, where to concentrate water, atmospheric considerations)
At the least I'm trying to advocate for say, pairing a French drain design with a rain garden or something to slow water down. In some areas they actually incentivize planting trees close to sewer drain areas since it helps manage water during flood events.
Not trying to be pollyanna and advocate for a sponge city approach evrywhere either, I'm aware of the issues with permeable pavement potentially leading to sinkholes and such (ref: https://x.com/waterhodl/status/1660307940451000320 )
Of all the natural disasters out there; volcanoes, wildfires, earthquakes, tornadoes, etc., the one that does the most damage, and kills the most people, is water.
Floods, tsunamis, and storm surges are absolute blockbuster bombs of destruction.
Up here, we had Sandy. It wasn't even that "powerful" a hurricane (I think Cat 2 or 3, by the time it got here), but the water that it brought with it, caused a huge amount of damage and death.
My basement flooded recently, I'm going to rent some equipment and dig drains/grade. Previous owners spent money on fixing cracks and painting foundation with stuff that always fails.
The best way to keep your basement dry is proper grade and if unable to achieve proper grade drains. It is literally that simple. This can help prevent formation of cracks and foundation problems as there is less pressure on them that way.
We cut a french drain into a below-grade room a few years ago. I was definitely happy to pay someone else to do it - cutting the concrete alone was a nasty piece of work and only the start of the job. Plus the unexpected footing running beneath an interior wall they had to cross below, such hard work.
I love the glimpse into topics like this, where one might initially think "what is so hard? Dig a trench and fill it with gravel" but it turns out to be way more complicated:
> It is hard to overstate the importance of properly filtered drains for dams. If you don’t believe me, take it from the Federal Emergency Management Agency in their 360-page report, Filters for Embankment Dams: Best Practices for Design and Construction. If that’s not enough, try the Bureau of Reclamation in their 400-page report, Drainage for Dams and Associated Structures.
To the point that:
> A civil engineer could spend an entire career just thinking about subsurface drains
I wonder how many of these stories start with him discovering one of these massive government reports. They always seem to pop up in his videos! It really is impressive how much invaluable practical information is provided for free by the various federal agencies.
I have to assume most of these reports, standards, and other documents end up being tax-neutral or better from wider dissemination of this info and/or propping up the status quo in engineering and construction.
Learning the basics of designing the gradation of sand and gravel filters is Soil Mechanics 1 (think 2nd year university). The massive reports are because of massive problems caused by poorly functioning or failed filters, but the basic premise of much of these videos is "give the first lesson in some subject without any math and actually try to explain things instead of typical engineering prof standards".
If you google "Gradation Design of Sand and Gravel Filters" you'll find Chapter 26 of the USDA's national engineering handbook, which will give the basics of how its done with some simple examples.
This is baby engineer type stuff, for the most part. If you're designing for big structures or complicated situations it becomes a much more complicated exercise.
The fact that it costs the government money to do things is obvious to the point of pointlessness. I could understand pointing out the actual cost of producing the info if you had it, but just pointing out the fact that it cost them money to produce some report doesn't add anything to the discussion.
Fun fact, in the French speaking part of Canada, "French drain" are fully translated to "Drain français" because of this quirk even though we don't usually translate proper nouns.
Great site! (though Unilever seems like a stretch, & gasoline is extremely contested).
This reminds me, my partner recently bought me some "Coffey Whiskey" because I like coffee, which led to my own discovery of another one of these (albeit one requiring a spelling oversight).
Julia doesn't count because it wasn't named after a person.
Even then, neither of those would fit the theme of the list above because they aren't named after their inventors (even though Ada is technically an eponym).
I think narrowing the theme of the list to just inventors is more an accidental result of the author's selection rather than their intended theme - eponyms seems to be the theme.
The point is they're unexpected. Elo is a great example, people tend to assume this chess rating system is an abbreviation, but it's somebody's name.
It's not unexpected that Ada is named after Ada. It is unexpected that PageRank is named after a person named Page rather than web pages. It may seem less unexpected if you happen to know who Larry Page is, but the same could be said for Glen Bell, if you knew who he was then it's "obvious" why the business is named Taco Bell right?
Everything I know about French drains I learned from this video. I was greatly amused, though, to learn that the "holes on top" vs "holes on bottom" thing is a bit of a holy war in that industry.
We have so many similar highly charged but largely meaningless holy wars in our industry that it was fun to see the same thing in a different one.
As someone who battled water in basement in the last few years:
1. Make sure your house is not at the bottom of a hill or swamp or whatever. French drain will not stop surface run off from uphill. You need to divert that from the top. Which is almost impossible since it's most likely someone else's land.
2. Make sure your gutter is cleaned and properly installed. And Make sure your gutters drain into a solid PVC pipe and channel that solid pipe away from your house at a pitch as far as you possible can. Most likely to the street, but that kinda mess with downhill and town drainage.
3. Have sump pump(s) in your basement and make sure they work and have back up power.
4. If your yard has flooding issue, then try french drain and/or dry wells. I found dry well work better on flat ground.
Just a side note, most french drains will fail at some point depending your soil and installer.
Do you have crawl space or basement? If you have crawl space, then you should encapsulate it.
- Increase airflow in your basement or crawl space. Add a pest proof window that you can open and close. Or operate a fan based on humidity or temp, similar to a gable/attic fan.
- Add a properly sized dehumidifier that pump water out of your house to keep the humidity low.
- Keep plants away from your house if your house is swamped by plants. Plants hold ton of moisture and it's great for your air, but terrible at humidity.
Search Youtube (and generally) for the topic and you'll get a bunch of building science stuff on the topic.
Just because your thermostat says the temperature is fine (and so does not run AC or heating) does not necessarily mean your internal environment is (totally) "fine". Perhaps, to start with, buy a (few) humidity metre (hygrometer) and see what various rooms / floors are in your house:
I think a french drain to a pit-type depression that can hold a few hundred gallons of water and drains across hours is the way to go.
And the french drain can be simply a slight trench. It doesn't need to be underneath anything. This worked for me and water runoff management around an old house. The lot had a funky grade, and all I wanted to do was get the water away from the structure. A little light pickax/trenching work got me what I needed.
I was curious with all the talk of drywells in the comments, so I had to calculate it. Here in Texas my roof produces 68 gallons per minute of runoff during a typical heavy thunderstorm.
No wonder the drainage ditch gets so full after a storm!
Permaculture uses very shallow ditches to force water to serpentine across the property. What doesn’t sink in shows up in the greater watershed much later in the precipitation. Not unlike urban rain gardens.
One thing I regret after moving into my new house was not getting a detailed list of drains installed in the property. I have lots of drainage issues and don't know if there is a drain there but inadequate for the amount of water we get, or just not installed at all.
A major lesson of home ownership is that it is a continual fight against water. Keeping water away from places you don't want it, and keeping water in and available in the areas you do want it.
This is absolutely true. I think half of the home renovation projects I've done in my life have been to either move water, or repair the damage from where water ended up where it shouldn't be. These are never the fun projects, but in terms of protecting your property, probably the most important ones.
Does the house have a sump pump? In our current house, which we bought with full knowledge of the issue, there was seepage and no sump pump, and we ended up having one installed (after negotiating down the sale price a bit after the inspection.) This involved jackhammering through the unfinished basement floor around the perimeter and installing a drainage pipe, then repouring that part of the floor w. inspection/cleaning ports into the pipe, along with a sump and pump in one corner. Works like a charm now.
There had been a drainage pipe but it was not working properly, probably being crushed or filled at some point by tree roots.
When I bought my house the previous homeowners legally had to declare whether or not there was a drain around the foundation. Very useful, it's the first thing we did and we never had any water breach the house.
Sorry, I should have clarified, I meant for drainage in the yard. We live in a development that's on a hill so 2 of our neighbors are on properties above us.
Yea, often these improvements are not well documented, you are right that it would have been easiest to ask the prior owners while they still owned it.
Anyone know how to maintain retaining wall pipes? Installed by previous owner of home, have no idea if they’re done properly or if they’re clogged or anything. Just want to keep that water moving! :D
You might be able to ask a plumber to snake a camera into the outlets and do a visual inspection on the inside. That said, it might not tell you if they used real, actual drainage rock + fabric as opposed to just surrounding it in dirt just via visual inspection, although I suppose based on the amount of dirt buildup you might be able to tell.
I've just recently this video on the engineering of Venice: https://www.youtube.com/watch?v=77omYd0JOeA -- relevantly, it shows how they devised an "active" drainage system that relied on the tide movement (both vertical and horizontal). The timestamp for waste management is 7:45, but I recommend watching all the video.
I found the part about clay cisterns fascinating (6:40). Does anyone know the trade-offs about lining the outside of cellar walls with a thick layer of clay. Would it be effective to pour a slab foundation onto a thick layer of clay? Or, to have a thick layer of clay, and then a few feet of gravel, and to pour a slab onto that?
I've always had French drains where I lived.
My parents' current house also has a dispersal drain for gray waters / toilets associated with a sort of septic tank (true septic tanks are now forbidden).
This drain disperses water under some sort of front yard (it's the countryside...) where the grass consequentially has a very high growth rate...
That depends on the principle, some are actually built to trickle and seep into the ground below.
Anyway I suppose that such concrete underground structures are often built on the cheap, and by the very nature of their content they're hard to inspect, so they're bound to develop a tendency to leak over the prospect of decades.
I suddenly remembered why, having previously found this channel, which is full of great information, I can't stand to watch the videos - the innocuous background music! Anyone else have this problem... where you're perhaps overly sensitive to music, especially non-fiction videos and podcasts? I find the background music unbearable.
I don't know much about codecs, but why isn't the music separated its own audio track so one can turn it on/off themselves in the browser? I'm guessing the current codecs being used doesn't support it, but couldn't/shouldn't it?
I have wondered if there is a cheaper, stopgap solution while I gather the money, something like aerating the soil along a path, the path that a drain would take, such that the water flows preferentially through the aerated soil.
We just had French drains put in around a farmhouse we bought as it had major drainage issues. They seemed to be working well last weekend during a few thunderstorms. Given the current tropical storm pounding NC I am glad we did it before all this rain.
This applies to houses as well, ideally you should have an air gap behind your siding to let moisture out (to prevent rot) - some common methods are strapping or ventilated rainscreens.
I remember there were PC Call of Duty 4 servers back in the day that would hack your game to add mods like paintball. Back in the day I thought this was cool but now all I can think of is how batshit insane it was to allow someone RCE on your PC.
I know valve was looking into running games within a containerized runtime (Pressure Vessel) on Linux which is really what should be happening. The fact that games run as your user and have defacto access to all of your secrets and keys is crazy.
My potentially dyslexic brain read this as “How the French drain in work” and pondered for a second: Hmm, I thought the French had great work-life balance and early retirement and all of that, what happened?
Soil migration is the number one failure mode. This is mentioned but perhaps a bit understated in the video.
To prevent soil migration you absolutely need commercial grade geotextile fabric wrapping the gravel and pipe.
You can buy pipe with much bigger and more numerous holes than the tiny slits depicted in the video. That also obviates the need to decide what orientation the holes should be.
Void space is the most critical factor when choosing gravel. You need a lot of space between the rocks to support fast drainage. Do not use playground pebbles or anything similar. Pay close attention to the type of aggregate you’re buying.
Calculate how much water you actually need to drain. You can use the “100 year flood” values for your locale to get an upper bound on rainfall, then multiple by drainage area. This is especially important if your roof is part of the watershed.
https://www.usgs.gov/special-topics/water-science-school/sci...
Sometimes there is insufficient gradient to move the water anywhere, ie the land is too flat. In this case you may be better off building a drywell, which is constructed very similarly.
https://en.m.wikipedia.org/wiki/Dry_well