Slab Foundation in Cold Climate // Problems
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- čas přidán 9. 07. 2024
- Slab foundations are cost-effective. However, they have some issues. The houses built on a cheap slab foundation are neither energy-efficient nor durable. Slab foundations in a cold climate are complicated. In this video, you learn the basics about slab foundations and see a proper slab foundation, which I recommend.
00:00 Slab foundation origin
00:36 Cheap slab foundation
00:55 Slab foundation thickness
01:09 Floor heating system
01:46 Wasted energy
02:18 Insulation problems
02:52 Durability problems
04:03 Sometimes lose and always win
04:12 A proper slab foundation
05:40 Beam foundation
05:52 Thank you - Jak na to + styl
No, your "better slab" is not better. You have thermal bridge between foundation and the wall (and heated floor). Just use XPS of appropriate thickness and density in the first design and you will have no problems whatsoever. Of course, you need to rebar it appropriately - ask engineer to do calculations. For heating you just need smart controller which will know the time needed to heat the mass correctly to not overheat. Can use outside temp to do preemptive heating and even weather forecast. Then you can use cheaper off-peak electricity to run your heat pump at night.
I disagree with you.
@@MarekKubi did you disagree with what? Wall blocks are exposed to heated inside air and at the bottom they rest on the uninsulated slab
@@andreycham4797 Uninsulated slab lay in the ground. When outside is -20, ground is still in +. So thermal bridge is not same cold as winter ouside. Small thermal bridge there is, just like on beam foundations.
About XPS I totally disagree. Never seen a proper tests about that material, so I am skeptical about it. I am sure, that xps also sucks moisture in. I dont have place to make some tests, but one day I will make that.
@@MarekKubi countries with colder climates, like northern Europe or Russia did use XPS under foundation for decades. No problem.
@@dmitryplatonov Yes, these houses still stay strong, but the energy efficiency has dropped during to density changes in that material. ( moisture + constant load)
Thanks for sharing your knowledge about foundations. I have a lot to learn ....but am impressed with the research you have done. Best Regards from the state of Washington, USA.
Thanks, this knowledge has came organically, I didnt do some research specially for that video ;) Nice to read, that my videos is being watched from so far.
1:27 that is a fundamental misunderstanding. Increased heating of the house doesn't start when the house get colder. Any decent temp regulator for a house relies on outdoor temperature, with more or less influence from inside temp. As it relies on the outside temperature it starts earlier, and doesn't increase more because the floor is slow.
Also, you personal skepticism is no reason for down playing a solution that have served over the years without the movement related issues you mention.
To add to this 'moisture' problem, most are built on 2-4 mm grovel that definitely breaks water movement. Also, many put in vapor barriers between the layers to stop ground gases to get into the house.
Thanks for your thoughts. Everyone can build a house according to their believes and a wallet. I like to read different theorys.
Like my garage i keep the floor at 15-18C and use external heater to make the room comfortable for me, such as diesel heater, wood/pellet stove, Electric Heater for when the big door opens, poof goes your heat.
Could also use a hydronic Air mover to use that hot water to get the air temp up quick while not sweating out the feet.
Past -20, my floor could be at 22c and the garage will still be around 8-10c. 22x22 15 foot ceilings, 16x10 Door.
But the feet are sweating!
-20 and -35c temps etc are brutal to keep a house warm on just floor heat, way too much heat loss if you do not super insulate the walls, lots of thermal bridging in a majority of new builds. Have a nice wood stove ready for the hot days to compliment the floor heat, As you should have redundancy with anything in life.
@@MitchOfCanada A normal garage in Sweden has around 200 mm (8 inches) of EPS under the concrete.
@@eleson00 that's only 1 heat loss area. There are 6 sides of heat loss. A garage door is barley r15
@@MitchOfCanada true, our walls are normally 120 or 145 mm ( 5 or 6 inches) in a garage.
But doors are a problem. Or rather, the concrete under the doors require special care to not leak all the heat from the slab by having one part of it outside.
How is the exterior insulation (in the ground) protected from moisture so as not to reduce its effectiveness (that you talk about)
There is ASCE 32-01 regulating construction of First Protected Shallow Foundation. This document highlight s all these issues.
I don't think Marek did a good job of explaining that his idea for a slab foundation (which is the same as the ASCE 32-01 Frost-protected Shallow Foundation) works on a different principle to the insulated slab. An insulated slab is just that; it has all the insulation you need under the slab, so the slab stays warm. A Frost-protected Shallow Foundation also insulates under the slab, but the 'insulation' is the ground underneath the house. The insulated extensions that run horizontally out from the house are aiming to keep warmth in the ground and under the house. Although there seems to be a cold bridge down through the foundations, there isn't because the ground under the house is kept warm by the heat from the house, and the insulating properties of the earth.
Well done !
All the foundations you talk about use so much concrete, but it's such a high energy material. Any foundations without it would be appreciated!
Heya! Just came across your channel, love it! I've watched the beam foundation video as well as the slab foundation and you mention you recommend beam foundation. But I haven't really understood why. Wouldn't you get better insulation values with a proper slab foundation as well as less risk for settle, as load is spread?
Hey, happy you found my channel. With beam foundation you have actually better insulation values, since foam is better protected from water. In theory yes, a slab can hold more weight, but in practice heavy houses is built on the beam, since a proper slab foundation gonna cost more. Main reason I suggest a beam is the depth of foundation. In case the ice gets under the house, it gonna raise the house. And usually (on a mainstream land) the deeper we dig, the more stable ground we get.
I personally gonna build on a beam foundation my future house. If you have good stable and dry ground, then both most likely dont have settle problems.
@@MarekKubi Hi Marek, I love your Channel, verry interesting. I am in Canada and I would like to contact you in private. How can I do this? Thanks you.
@@celestinca You can send me email: kubimarek@gmail.com
Marek, another informative video. You make some interesting points and I am sure some folks will have many comments in response.
It is interesting that many builders still put rebar or steel into concrete. Why?
Long term, the steel will eventually oxidize and deteriorate the surrounding concrete.
If the design, the materials and the installation are correct, there should be no need to install steel reinforcement, especially for light construction which residential buildings are.
Steel keeps concrete together. Even on very stable land there are vibrations, which will crack concrete. Concrete and steel have similar expansion rate to temperature. That is why we use steel.
I believe the basic premise of this video is incorrect. A insulated raft/slab foundation installed as per a structural engineer’s specification will not suffer from any of these issues highlighted in this video. In the UK a structural engineer’s PI insurance would be on the line if the structure of the foundation started to degrade within 10 years. Not sure why Marek describes the insulated raft/slab as being cheap, it is no cheaper than a block and beam foundation to construct a foundation this way.
You're definitely wrong about most of this. The control loop for in-floor heating doesn't just measure the air temperature of one room at one point, it measures the temperature into the loop and out of the loop in order to tune the PID. I've never seen a construction crew fail to correctly compact the ground, so that's not a real issue. The bearing capacity of EPS foam is higher than any soil, so it's actually stronger to use foam than to put a slab directly on the ground. Also, in a cold climate you absolutely must have a complete thermal break from both the ground and the air, on the outside of the structure. In your diagram you show a slab directly against the ground (which would be 1-2C) with concrete block bearing directly on it with no thermal break. So your walls will be extremely cold. The only advantage to your design is that dumping a ton of heat into the ground raises the frost line.
Even though it takes longer to initially heat a bigger slab, can't that be a good thing? If it is insulated properly, it's going to stay warmer for longer.
Yes, you can benefit from that, when you have 2x cheaper electricity at night. I personally like more, when I can regulate temperature down, when family is at the work and start to heat the floor before coming home. If you are doing home office, then using accumulation can be cheaper. People prefer to sleep at the colder temperatures as well, so heating only living room at the night is not so cost-effective as heating all rooms.
what is that brick like structure you drew at 5.19?
Insulation.
@@TheRealFOSFORwhat do you think about using icf to have insulated concrete wall on both sides?
that was helpful. thanks
Thanks for your support!
What happens if water gets in between the two layers of concrete in your example? Since there is hydro isolation at the bottom- that seems alright, but if due to flooding (burst pipe or something similar) water gets into the insulation from the top- be it seeping through concrete or through the edges?
Hey. While heating the concrete will slowly dry the moisture out. That is why hydro insulation is only below.
does this work on seismic countries?
Hey, I dont know, since here there are no earthquakes.
For your improved slab the lower slab is not needed, just use stone.
Very nice but that will so expensive very few people will be able to afford such a system. Imo
Yes, true story.
👍👍
What about a dual, or even triple pour with embedded foam boards, like tilt up walls? heat pipes in the top layer, no foam over footings.
Sounds expensive and complicated for me. If i got your point correctly?
@@MarekKubi very similar to your design, the initial concrete layer is poured with footings and rebar. when still wet, the foam boards and rebar connectors are placed. Next day add hydronic pipes, steel mesh, pour, finish. Membrane could be before the first pour. No wall, or bitumen, other than perhaps a bitumen membrane.
@@7Trident3 Never seen that before, but I assume it's the same technology as with sandwich panels on apartments. I think it is a strong result overall. Maybe this rebar, which goes to the lower panel is a little heat energy sucker? Also not sure, if this heated panel is thinner than 10cm? Otherwise, we have materials and technologies to build very durable foundations. But optimization is what creates the problems.
Aitäh, väga hariv. Kui tahaks keldriga, kui palju muuta tuleks lisaks sügavamale kaevamisele?
Tänud. Kelder nii haruldane tänapäeval. Esiteks paljud hea infraga krundid on liiga niisked keldri ehitamiseks. Teiseks inimesed ei hoia enam kartuleid talvel keldris. Mina näen mõistlikumaks ehitada kelder krundile maa sisse. Või abihoone alla pisike.
You need heatloss into the ground to prevent frost heave of the foundation
Idealy when you compact soil very well like engineer is specified in project and you add one plastic under EPS/XPS like radion stopping plastic then i think you dont have this issue with water migrating into your isolation and ruining R- value(or U value) over time. Why slabs brake is that contractors wants to cut corners.
Yes, your last sentence sums everything. Nowadays you can build in to the sea also ;)
Here we use PolyUrethane (pur) insulation instead of crappy Expanded Polystyrene (eps).
Spray foam under the slab 2-3” it’ll be a continuous strong seal all the way through you can even spray the side of the slab after it’s poured
Foamglass insulation to be used instead of xps boards
I think it is very expensive.
@@MarekKubi Not really. In the US where everything is more expensive... it costs the equivalent of XPS insulation boards plus the required amount of gravel and sand.
Factorio man has been found lol
Hey
But isn't your slab has a massive thermal bridge on the sides? Bottom slab would always be cold, the same as the ground, and it'll absorb the heat from the outside walls and your house.
I have never liked the idea of the foam under slab engineering. The foam has a 'crush' value and is far from water proof! Any high ground water is going to soak that and decay the product I don't care what some to most say. I have worked and operated my own HVAC business for 43 years and all the homes on Concrete stem with beam and TGI floor systems have less heating demand, thus less fuel. And foam insulation under the garage slab, never in my house! A large Truck or heavy machines will overstress even a 5" slab with that crap under it! The years just haven't caught up with the problems yet!
True story......
Marek, thanks for your video.
But, as I understand, you have no experience with slab on XPS, (not on EPS) so your conclusions are not very correct. This slab is SUPER efficient. I have a house (framing house) on this foundation in very cold climate (-20C is middle temperature of Jan). And it's very energy and cost efficient. I warm my house with electricity and spent less money than my neighbors for logs!
Good bye.
Youre welcome, thanks for watching and sharing your experience.
Everything starts from a soil. Here many homes are built on a damp soil. There are more risks. Your house can be super efficient, but your neighbour may build a new same size house and it can be even more efficient.
It seems like you're speculating and don't have proof...
Can you say EXPENSIVE and OVERKILL?? Average home owner moves every 5-7 years. Ask the idiots changing out perfectly good single pane windows for dual pane windows for a lesson in ROI.
Housebuilders aren't building for the average home owner's occuplation, otherwise houses would fall down after 7 years.
Kas sama kehtib ka külma garaaži rajamisel.
Külma hoone puhul on külmakergete oht suurem. Liivasel pinnasel on vähetõenäoline.
I've come to the conclusion, there is no good way to try and stop moisture all together. You just have to build everything so it can breathe. If you try and bottle something up so that moisture cant move in to something like a concrete footing, water will find a way in and you just made it impossible to dry out.
Hey. Nothing wrong with wet concrete. There are many bridges inside the water. Only bridges may use an special rebar, I dont know. Rebar needs air and water for rusting.
@@MarekKubi All I know is water freezes and expands and also forms all kind of microbial growth that you don't want anywhere near your living area.
@@TheRealFOSFOR It has insulation and will not freeze. Under the house anyway is wet and nature growing, so I still don't see any problem. Leaving ventilation behind the insulation will create a freezing problem.
ridiculus concept and detail!!!!!
Poor insulation. Not better.
Yes, a beam foundation for good insulation is the way to go.
You fail to provide any evidence for your claims.
Sorry to say this is one of the most uneducated inexperienced and misunderstood of a better slab.
It's sad to see this type of misinformation being propagated, there are so many problems with this young man's design it's not even funny.
Might wanna get an English speaker to do your vids. I can't understand you
There are subtitles for people like you.