Residential Foundation Problems
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- Опубліковано 3 кві 2023
- Expansive soils are the most problematic type of soil for residential foundations. One in four foundations in the US experience some type of foundation damage. This video explains common issues with expansive soils and mitigative measures that help solve the issue in some cases.
Geotechnical Series Videos:
1. Understanding why soils fail ( • Understanding why soil... )
2. Understanding the Soil Mechanics of Retaining Walls ( • Understanding the soil... )
3. Geotechnical Analysis of Foundations ( • Geotechnical Analysis ... )
4. The Leading Cause of Foundation Failures ( • Residential Foundation... )
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References:
[1] Groundworks, "Top 15 U.S. Metro Areas with Foundation Issues," Groundworks, [Online]. Available: www.groundworks.com/resources.... [Accessed 23 March 2023].
[2] L. Jaakola, "Properties of Deep Weathered Swelling Clay and its Stability Implications in Tunneling," NTNU, Trondheim, 2019.
[3] L. D. Jones and I. Jefferson, "ICE Manual of Geotechnical Engineering," in Expansive Soils, ICE Publishing, 2012, pp. 413-441.
[4] L. D. Johnson, "Overview for Design of Foundations on Expansive Soils," RDT&E Work Unit AT40 E0 004, 1979.
[5] J. D. Nelson, K. C. Chao, D. D. Overton and E. J. Nelson, Foundation Engineering for Expansive Soils, New Jersey: John Wiley and Sons, 2015.
[6] J. D. Nelson and D. J. Miller, Expansive Soils: Problems and Practice in Foundation and Pavement Engineering, New Tork: John Wiley and Sons, 1992. - Наука та технологія
I’ve spent 40 years in Civil Construction and agree with your comment about workers not appreciating the importance of certain aspects of their work. This is why, as a Project Manager, I would identify such risks as part of the Risk Assessment for the project and ensure that staff are aware of critical aspects of their work. I slept better at night knowing that critical quality issues were not being ignored through lack of knowledge
thanks for this, wish more builders / construction workers / tradespeople cared about quality
@@bruce-le-smith While there are scammers, the immediate cause most often is improper communication between design engineers and site construction. It's pretty common that the on-site reality will diverge from the plans, which means adjustments need to be made. It is therefore crucial in these situations that the on-site workers know what design elements are critical (and ideally basic knowledge on why) and which ones are more flexible to avoid the good-idea fairy making a mess of things.
Carpenter here, there are plenty of us who do the full extent of our duties. Please Retain your best guys and circulate them around your team so they share their knowledge. And please stop leading with how bad everyone else is, our industry would benefit to lose that idiom.
I can see by some of the comments, people (including myself) still don't really understand this expansive soil problem. Moving from Michigan to the coastal bend of Texas, I got to see first hand how different the soil is and how you simply can not use the same solutions to mitigate water problems. So many times I wish the builders would have places water hoses and sensers every square yard or so under my house so I could react before my foundation cracked.
It is so hard to explain to my northern friends and family that we do not have basements because of destructive nature of the expanding soil and our houses are basically boats floating on the ever changing ground.
It's a nightmare to deal with. The best course of action is probably to prevent it from happening in the first place by proper design and construction (not very useful saying it now, I know..). Mitigation is difficult, expensive, and case specific
We used to live in Winnipeg Canada, which is famous for (among other things) - cold winters and Red River (clay) gumbo. Our last house was built on piles that went 30 feet into the soil where the moisture content is stable year round. Proper drainage is emphasized and people generally know to water around the foundation if the summer is very dry. But the basements/foundations have to be put 6 feet down below the frost line, so generally they are pretty stable. One difference is that the basement floor is usually floating and may (will) move. When building partition walls in a basement - this MUST be taken into account.
Interesting, just south of there most are not built like that, just a 8-10 foot basement and drain tile around it, along with I have never heard of a floating floor basement. Very interesting how much difference is in gumbo over a small area.
What's the fix? build the interior walls 3/8s short and hang the top plate on the nails?
@@jessedevlin9489 exactly. Interior framed walls are attached to the floor and the connection to the joists or main beam are designed to allow movement otherwise the framing can actually lift the house off the foundation. The soils are extremely expansive with huge problems keeping roads reasonably flat.
I'm in Ashland WI. We had Lake Agassiz here during the last glaciation. We've got thousands of meters of red clay beneath us. ALL buildings here are affected by the clay, plus all the streets and sidewalks
@@michaelfisher6354 most of the clay on the Canadian prairies would be this type then wouldn't it? Specifically I'm talking about north central Alberta. The basements are usually 8 feet deep. There's plenty of randomly cracked foundations. Not as much on the corners as mentioned in this video.
Raft slabs are a possible solution set out in AS2870 which is the Australian standard for residential slabs and footings. That and keeping water away from the foundations are the biggest challenges. Here in Australia in 'Highly Reactive' and 'Extremely Reactive' soils the movement can be in excess of 100mm due to differential moisture content. A typical 'H' class footing system for a residence would be beams in a raft configuration spaced at no more than 4m apart heading in either direction. Continuity between beams being a major consideration. The prescribed standard we use here for say a 'H2' class (not even the worst category) for an articulated masonry house (brick veneer say) would mean 700mm deep footings with 3-N16 bars top and bottom so some pretty heavy duty stuff.
You took the words right out of my mouth.
Angkor Wat temple in Cambodia has a moat around it that keeps the soil wet always to avoid these problems.
This explains why the Circuit of the Americas (COTA) near Austin, TX (race track) is constantly bumpy regardless of any mitigation done by the owners.
Thanks for this informative and entertaining insight into FOUNDATION FAILURE. Here in mid-western Canada foundations are typically underpinned well below frost, I have seen big mansions built on old swampland (after several years of the site piled high with backfill) such that after soil test analysis, engineers specified over 200 screwpiles to depths of almost 30 feet below the basement footings. This was at a 8500 square foot Two-storey walkout.
I heard that for decades it was common practice for Geotechnical engineers in Texas to borrow a swell formula from TXDOT for commercial and residential building construction. The formula was reasonably sound in the context of building highways of modest width where the road is built up with ditches on either side. The formula includes a 1/3 factor that assumes and accounts for the highway subgrade not being horizontally constrained and thus much of the swell can move outward rather than upward.
The practice of borrowing this formula and not understanding its original context led many engineers in Texas to essentially underestimate swell potential in buildings in many areas by a factor of 3. So 4 inches estimated becomes 1 foot in reality.
I'm a mechanical engineer, but the concepts of civil engineering have always fascinated me. Loved that you put references and noted them in the CC. Also was not aware of clay deposits and the water in the great plains during the Cretaceous period 😬 My late grandfathers house had a foundation failure in the basement in OHIO, likely from freeze/thaw for decades, but it was only the buckling of a basement wall, so they put slowly tighten-able steel reinforcement beams on that wall to fix the foundation to lessen the cost
I won't buy Spec Homes - too many cut corners! So, I designed&built our home with 40"x24" rebarred footings, 3-foot wide soffits around the entire perimeter. That, exterior insulated foundation and 6" gutters and 4" downcomers connected to u/g 4" PVC that drain to two 1,000g leach tanks buried 6' below our basement floor. 18 years and no sign of foundation movement and zero moisture evidence in basement.
That's amazing!! 👏 My guess would be that your solution would still end up cheaper compared to someone who has to do underpinning or other mitigation work after the house has been built. Good planning can pay off in the long run. But I doubt developers would go that far when developing residential areas.
That's the way to go! Did you get any grief about "overkill" from subcontractors or lenders?
My sister is experiencing this problem in the UK south coast area. A tree at the side of her house sucked up all the water a few summers ago and caused the front half to drop and cause cracks throughout her house. Her insurance is going to do remedial work this year. When I saw your graphic I sent her this video. It was brilliantly explained and presented. Excellent work and many thanks.
Thank you General, I hope your sister also finds it helpful!
Great information provided.
Excellent work. I teach geotechnical engineering and will share this video to my students each year. Thanks. Please do a video on consolidation.
That's great to hear! While you are there, check out our other 3 videos on soil mechanics and geotech applications. You may find them useful as well. Cheers!
As a geologist that works as a consultant in geotechnical solutions, in the south of Spain, we also have the same problem with expansive clays, that are from the miocene and very consolidated, so they push really hard upwards, and cause serious problems. The general way we fix this is by using semi deep foundation (caissons) passing a -3,00 m depth from the surface since, that area is inside the active layer of the clay. In other occasions we also use slabs, with 3 or 4 layers of structural fixed-filling, that will cushion the area and mitigate the expansive movements.
Thanks for the comment Alex, it's great to hear from other parts of the world and how you have managed to deal with these issues. Cheers and thanks for tuning in!
I'd love to see a video on steel mesh/rebar in concrete. What it does, and more importantly placement in a slab (top 1/3, bottom 1/3, or the middle). Which you do, when, and why.
I have a friend who has a house built on shale. The house has cracked through the centre . Cracks open across the ceiling and walls . It appears through these cracks , that the outer edges have dropped and the centre has cracked apart .therefore the foundation concrete slab has flexed. As a curious person and engineer not civil I am keen to understand what's going on ,how to possibly dampen the problem and learn what measurements to make to work out what's going on. The owner claims the builders drilled pillons into the ground right down to shale rock . I contemplated making measurements from a reference point away from the house to a grid set of points around the house slab via water pipe level to determine the flex over time. I also observed some of the roof battens snapped apart at the weakest points probably due to the flex. I know because I repairs one or two due to aleak in that roof. Thanks for video
I try to tell out contractors the purpose of our products. We use on site (typically clay) behind our walls and a couple of contractors have installed our drains backwards to the point where the water just collects behind the wall and drastically increases the bearing load 😬
I'm glad you showed me 8:42. I had a contractor ask if we had any solution for his outer wall cracking and I designed exactly the right picture for him on the fly. I've always wondered if it was a good design 🙃
Reference [5] and [6] by J. D. Nelson have more in depth explanation about water barriers if you need more details.
Well done!
I have nothing of substance to add besides that you made another great video. Thanks for all of the work!
Thanks tomsko!
Surprising that this content doesn't have more views
Hopefully one day 🙏
Drain tile and sump pumps are becoming more common as time goes on, in some areas they have been common for decades.
I’m a carpenter from the western prairies of Canada and that has been standard practice for quite a while. I now live on the west coast and most new construction has extreme drainage mitigation strategies. Starting with large roof gutters that are directed into the structure’s sump pit. Secondly there is also drain tile installed that directs water to the street drain system. And finally there is code requiring proper slope for backfill.
I found this whole approach interesting and so completely different from the dry prairies to this very damp rain forest. The foundation is just the start of the differences, such as damp proofing prior to exterior finishes, but that’s another topic.
Thanks for the great conversation starter. I’d like to hear other challenges builders face in different regions.
Cheers all
Excellent video.
Killing it with those videos !
Thank you 🙏
Is increasing water conductance horizontally ever done to reduce moisture differentials? Either with drain lines, wicks, or some conductive but not expansive soil?
Extensive foundation work was videoed in building Giga Texas. See Joe Tegtmeyer.
Seen this here in canada as well; in toronto near lake ontario. Extensive mess
perhaps if the insurers leaned on the builders to build more capable foundations, the insurers would have fewer payouts.
Hi...I m just trying to build my house in hyderabad in India. Our plot has soft soil with a mix of clay, sand and particles made difficult by water. The plot is close to a lake and adjacent to a well that was filled and a park constructed on it. Thd SBC is 12 to 15 and accordingly the engg designed the isolated footings ranging from 6 feet to 11 feet. The earth was dug to 11 feet and going deeper was only helping more water seep. So at 11 we added bed of 1 foot sand. 6 inches of pcc. Laid the footings. Since the volumns would now be lenghtier he added a tie beam. At 5 feet the plinth beam would be laid. Additionally he added a retaining wall between the the beam and the plinth beam.
I work with mechanical (push/helical) resistance piers in the USA and in now Australia. What are your thoughts for Polyurethane injection "underpinning"? No lateral support and temp fix for vertical (settlement & stabilization only).
Duraflex-usa might be a solution to sealing the soil around the foundation, making an impermeable barrier to keep the clays from expanding and shrinking. Let me know if you are interested. Excellent soil stabilizer too.
I had heard that one way to control changes in soil moisture was to constantly keep the soil wet under and around the foundation so it never drys out and shrinks. This would only work if water was plentiful enough and cheap.
This method was tried in the Raleigh/Durham-Chapel Hill market for a number of years by one particular engineer/contractor collaboration......with dissaterous results. Push piers or Helical piers are a much better idea.
What about the reverse?
Levelling out the moisture differential by creating a perimeter rubble ground drain, protected by Geotech fabric.
We once constructed a preeniginered bldg on a post tensioned slab... it moved but never cracked
I think I begin to understand the root of the problem at the words "clay soils capable of great expansion and shrinking." Good-bye foundation.
How deep are these foundations? Is it possible to dig below the expansive soils? In the Northeast US, we typically have concrete footings dug 11-12 feet, then basement walls poured on top of that
the real problem with Texas is aggressive and unrestrained construction
the houses are built as fast as possible and are bought and sold like futures
the problem is so great that modern texans do not plan on keeping homes as long as in other states. it is anticipated that you would move to a new built house many many years earlier then average.
Can’t you dig below the drought line or frost line in Northern regions and set your footing?
Ayyyyy Bryan, TX shoutout! We have tons and tons of clay here. It's a thing.
Most of our construction is pier and beam to avoid this. Even so, it's not uncommon to need a house leveled, or cracks to appear in buildings.
Grapevine/Colleyville has its share too.... 🤠
I have never been there myself, in fact, I had never heard about Bryan until now. It's amazing that there are viewers from there. Thank you for your comment! 🙏
The video footage accompanying your assertion about problems in the UK is not filmed in the UK. An American electricity meter is visible on the side of the house.
Could you replace a non-rectangular (vertical cross section wise) of the foundation with different backfill? Would a rounded or triangular bottom affect the problem of the edges being affected faster, maybe smoothing uplift distribution?
Would that amount of material be prohibitive?
I like your videos why do you make so few.
What about drilling and sucking out the fluids in the earth?
Trees roots and vines cause most foundation fails in my area. ....and Ground Hogs.....
Tru story at the 6:09 mark fixing problems now
1:00 all these regions have more than one thing in common. Among other they are a part of the Anglosphere...
haha 'all these regions have one thing in common' British people live there and build the same type of houses in all those different places. but kidding aside great video, we live in an are with lots of clay, and boy does it move around!
This is a HUGE problem in West Texas. I once owned a house in Abilene, TX. The slab is just poured onto the ground. There is no compaction or grading, it's just poured and left to cure. The after a few years of wet and dry seasons, the grout shifts and CRACK !! IDK if there are any regulations in Texas about residential foundations ?? C'mon now at least have a simple law about this. But Texas is a wasteland that you don't want to live.
Add Colorado to that list of miseries! Bentonite clay is awful.
At 6:36 you say that you read 100% of the comments. You also asked for ideas for content in a post/pre tension video I saw. Good, So could you do a deep dive on moon phases and the numbers that go into megalithic structures? How were they built, how were such massive granite stone cut or moulded or moved, (Incas), and of course this would be an opinion piece on the producer of said deep dive.
Hi art1, I do read all of the comments. Thanks for the suggestion, I have heard about these things on Joe Rogan's podcast. It's indeed very interesting. But I am afraid I am not qualified enough to talk about those structures.
@@TheEngineeringHub FROM WHAT I'VE SEEN, YOU ARE VERY QUALIFIED. WE'RE TALKING ABOUT NUMBERS AND SUPPOSITIONS. THANK YOU FOR ANY CONSIDERATION, ANYHOW.
@1:00 I thought you were going to say, they were colonized by the UK. I was expecting a building style to be bad...
Haha I didn't think about it until you said it 😅 it would have been a great line 😄
👍
Are are on sale half off ;)
Up lift force.
I read in an article that this all may caused by planned obsolescence.
No surprise that the cowboy state has the most cowboy builders.
The British are like Texas is what's important here.
It's ridiculous how you not only use some outdated banana-like measurement units, but also mix them with modern ones. 10 pumpkins per square banana, ahaha😂😂😂
I'm trying to be inclusive of everyone. I personally also prefer metric because I grew up in a metric country.
I'm expecting charlie from the thumbnail
"Why are foundations are failing" what??! Maybe update the title to review the first or the second "are"
Thanks brass, embarrassing. It's fixed now.
@@TheEngineeringHub I've done way worse, believe me! Always glad to be corrected. Thanks for the great content.
👍🧱
you are a tipazo
Putting down such a strong foundation to build a house made of twigs (American standard house) doesn’t make any sense!
Have fun fitting doors, windows, plumbing, stairs, walls, cabinets, etc etc in a building that shifts like twigs on mud.
We build with lumber because 1. We have an entire continent covered with it unlike most of the world, and 2. you want it to breath, to flex, to expand and contract, without cracking and causing damage like brick and concrete does. Also, in North America, we have the money and ability, not to mention legal ability, to remodel usually at least once or twice in our lifetimes, and wood makes it easy to tear out a wall, put up another, add on, tear down, or just completely start over and rebuild, much faster too, compared to brick or concrete. Also in areas like Texas where straight line winds and tornadoes are a thing, you do not want brick. You can read any report of a tornado hitting a school, which are usually made out of brick, and it usually includes a report of a brick wall falling and killing children and people under it. Wood and sheet rock does not usually kill someone when it falls on you, and it's ability to flex and move is what causes the pictures of the damage you see: the outside walls are damaged, the roof is probably gone, but the interior rooms are intact and where people survive without major injury.
If you 100% wanted a non frame type building, your only real safe option is poured concrete, which is insanely expensive and completely unnecessary, unless you are building a bomb shelter.
@@J-1410 it’s not what I said
@@AdaptableAutonomousHouse
You alluded to it.
The “American houses are built like crap” schtick is denial of building science.
I am a Canadian Framing Contractor and I stand behind our "twig-buildings" 100% Comments about weak stick-framing and twiggy trusses are proof of the lack of understanding of engineering principles and just how much engineering goes into modern platform-framed houses! 😂