Insulated Slab on Grade Foundations (For Architects + Builders)

[@ASIRIDesigns]

*Read the full article on insulating slab on grade foundations here:* asiri-designs.com/resources-1/f/insulating-slab-on-grade-foundations

[@WangAiHua]

Great video--one suggestion--get rid of the stupid music---it is distracting!

[@RSEN1]

Great explanation! I am a DIY hobbyist, and I am always very interested in the theory of building. I have never come across such well-summarized explanation videos. Additionally, with every video posted, I also have to conclude that my house, unfortunately, was not built to these standards. I will definitely use these videos as a reference for future DIY projects. Thank you so much and KEEP UP THE GREAT WORK!

[@ASIRIDesigns]

I'm so glad to hear it was helpful! Hoping to cover the niche fairly broadly to address common design/construction mistakes that can result in failures. Stay tuned for more!

[@mikeokeeffe3495]

Iv been looking for something that explains foundations in this detail for ages thank you so much and the website is fantastic

[@feeder1963]

If youur a DIY go kzbin.info/www/bejne/hoapnGWtm9-BiLcsi=2zhtDhM3kbbgNBgs He uses this technique when he building slab on grade .

[@feeder1963]

kzbin.info/www/bejne/rGTRmaKnrtibqsUsi=X4LrC8_r8eNGOAH6

[@VRtechman]

😮 kzbin.info/www/bejne/rGTRmaKnrtibqsUsi=EC0ShpqUsNynikqz

[@spark-taco]

Wow! tonnes of useful info packed tight in a short time. Thumbs up.

[@jamesjensen5000]

With increasing prices for sheets of rigid insulating foam reaching above $70 per 4x8 piece, and calling for double layer, it is possible that a +25 psi spray foam product can be developed and utilized under a concrete slab and utilized on the foundation wall as well. Add to the sheet cost the time to cut and assemble, eliminating “iceberging” and eliminating expensive hard to handle adhesive sealer tape, and benefits of an air tight seal around pipes, columns and other openings… the cost of dense spray foam might be less overall than rigid sheets… and the cure time of the spray foam could save additional time before concrete pour, or reduce costs of flashing on sills or around perimeter junctions.spray foam application over compressed crushed rock would level well and help consolidate the compressed mass. I predict the application of dense spray foam will become common practice in the near future.

[@freemancustomstairs]

Couldn’t you use closed cell foam?

[@lauriviik]

Really? Where im from your typical underfloor polystyrene pack of 0,72m3 (thats 7,2m2 (77,5sq.ft) in 100mm (4") thickness) costs 60 dollars

[@JustMe-pc2ii]

There is a video I watched where they did exactly that. Apparently they were in Alaska.

[@CMCraftsman]

We spray closed cell over the crushed stone in the basement and 2’ up the wall feathering it to nothing. After the concrete basement floor is poured over that and the first floor is built, we continue the spray foam up the inside of the walls and into the rim joist.

[@stupendas101]

this is probably doable but the problem is that if you get variations in density, hence compressive strength you are likely to get many more cracks in the concrete. It is much easier to control the uniform density in a factory. With that said, the companies are indeed gouging and importing insulation from other countries is cost prohibitive because they take a lot of space hence shipping cost per panel will be astronomical. The domestic suppliers know this hence they know they can gouge and get away with it

[@CMCraftsman]

At 3:04 where you’re using Zip liquid flash, I’ve found that Siga Fentrim is much easier to work with and much less messy. If you live in the northeast it’s readily available and you can get it in a day or 2. It doesn’t require primer and sticks extremely well to concrete and zip sheathing. Also, at 3:24, if you can get there to roll the water proofer on the footing after it’s cast before they set forms, you can eliminate that capillary action from the footing to the wall.

[@TheSepetto]

I hope you find much success and make architecture community understand that it needs to be more like you.

[@SchondorfEnt]

This is the most clean details we've come across. Amazing work. It's evident that you're really capable in the field. Any builder that would have you on their project would be blessed.

[@SailingCatamaranElement]

I'm starting to see construction of footings with a vapour barrier below and up both sides of the stem walls to remove / reduce the capillary water movement from the base soils...

[@portnuefflyer]

On a related subject somewhat, I've never used anything but water in 4 different radiant floor homes and shops, no anti freeze, for the last 40 years. In the Idaho mountains, so real winters, the homes had basements but the two shops were an insulated slab with insulated foundation walls to the top of the footings. Even after a couple weeks of no aux heat the slabs never got below the low '50's.

[@davehoward3645]

In the south slab staying ground temp is helpful

[@coasttal123]

After compaction and setting all plumbing and electrical for the slab, I termite treat the soil, cover with 15 mil plastic, overlap joints 12", tape joints, then spray foam the entire area, set rebar, and then pour a monolithic slab.

[@ASIRIDesigns]

This is a fantastic method as well, you see this strategy a lot in the Northeastern US.

[@MrWally3433]

Please provide this detail for a full excavated basement, with Zip R. I am struggling with where to put the wall insulation (inside or outside). I do not like the idea of trying to match insulation thickness with sheathing thickness (and/or overhang). This is also complicated for homes with both brick and siding facades. With Zip R type sheathing (or equivalent) soon to be the norm, I think that dealing with the aesthetics of a continuous insulation barrier is going to be challenging.

[@luishumbertochavezrodas3619]

So for a tropical climate like central America's, the first strategy would be most beneficial, if I understood correctly. Really good stuff, thanks for sharing ASIRI Designs!

[@lyndleshelby6291]

Extremely detailed explanation and very informative. Thank you for sharing your knowledge!

[@ASIRIDesigns]

Thank you for watching! Glad it was helpful!

[@secretlake5528]

Definitely going with the last option. Thanks

[@ag-om6nr]

This should be Building Code ! As well every contractor and building inspector should be required to take classes ! The public needs to be educated as to how important this is ! The extra cost may mean no granite countertops , but the result is building that will last !

[@eliinthewolverinestate6729]

Great video. I insulated my block piers and under my floating slab. I have a passive solar design so trying to take advantage of thermal mass in the floor.

[@ChaseSmallCraft]

GREAT video - until now I could not feel comfortable with slab on grade but the system described in last part of video. I wonder if spray foam could come in here rather than fitting the foam boards.

[@ridgetopdave2638]

Good clean and sensible insulating details. In the PNW our energy code only requires 2" or R-10 rigid under heated space SOG. However, from personal experience, I would use at least the 4" as you have detailed because 2" still leaves you with cold floors. Also typical is to install the vertical R-10 to the inside of the stem wall with a 45 degree angle cut at the surface rather than ledgering the insulation into the stem wall but I can see the benefits to your detail.

[@ASIRIDesigns]

Thanks for watching, and well said! You could absolutely bevel cut the rigid insulation on the interior skirt if you wanted a smoother transition between floor slab and stem wall.

[@صحتمندلوگ-صحتمندمعاشرہ]

Very nice and compact video that is well insulated from unneeded and lengthy details :) I was about to ask you for the source document but then I saw it pinned to this video. Thank you very much.

[@johnpooley3]

Excellent presentation!! If you could please do a video on foundation styles for ledge I would thoroughly enjoy it. Think Olmsted’s ‘Plan for a small Homestead’ but smaller, steeper, and shallower soil

[@ML-er9jt]

This is a great breakdown on how to install these kinds of slabs. What would change with a heated concrete floor?

[@philiparmand3534]

We always do this. We use Rockwool Comfortboard and a woven vapor barrier so rebar or re-mesh doesn't easily puncture it. We have also used closed-cell spray foam under the slab with great success. We have major termite and carpenter ant issues here, so we often add diatomaceous earth and/or a heavy dusting of concrete onto the gravel before spray foaming.

[@baptistlion4060]

That’s interesting about diatomaceous earth. I might do that. What state? I’m in Arkansas

[@christianfekete]

I would suggest to extend the outside wall insulation past the top of the foundation. The foam sill gasket is still a thermal break that could be covered

[@pacodefrancis7235]

Great video and good stuff! Thanks. Now for the last assembly (frost protected shallow foundation, or FPSF), what about using a “reverse monoslab” assembly? I saw this assembly on Bondo Built’s channel and it certainly piqued my interest. 8-12” of graded & compacted crushed (clean) stone, then put 2-4” of XPS foam on top of that, then bring in 8-10” of crusher-run mix (1” stone with fines) in the middle, such that your footer is 12-16” thick and your interior floor slab is 4-6” (or whatever is specified). It seems like it’s a much easier way to ensure continuous foam coverage around the haunch and turn-down. The sidewall foam detail and sloping below grade curtain is the same.

[@fredio54]

Thank you for this. I cannot get my head away from the last option. All the others have far less thermal mass which bothers me. In a non cold climate you could also put an uninsulated slab on grade and seal it, then lay a timber floor over it with insulation in it, but this has no thermal mass.

[@austinw638]

This is very well done. Strong work!

[@marshallbeckawilliamson1458]

Wonderful job clear/concise in the drawings back that up very well. made perfect sense😊

[@gregcharland]

Dr. Joseph Lstiburek has been making videos on the correct way to insulate a building with exterior foam or mineral wool for more than 10 yrs. I think he wrote the code book for it that building departments use today.

[@raymondtremblay489]

Wow so much important and detailed informations ...thank's , but why the annoying unnecessary music !?

[@maxpikhteryev7880]

Great details and explanation. One question though. How do you install flashing from WRB to foundation (between the foundation and the exterior insulation) if the exterior insulation is already in place? Or am I missing something?

[@jeffp1289]

looking for information on how to retro a shallow footing to FPSF. All the videos I've seen show new construction.

[@2point..0]

I really like your illustrations and want to learn more, so I subscribed and Liked it too.... I will be designing a single story home and it's I.C.F. foundation will be made from I.C.F.'s and foundation is split into two sections that needs a stepped footing, meaning one side (left) being the kitchen/living (radiant floor heating) it will be I.C.F with Frost Protected Slab and the other side (Right) will be for the 2 bedrooms and 2 full Bathrooms, over a small (radiant floor heating) basement.... P.s. great idea that you mentioned about the dimple mat applied over and down the horizontal wing of the ridged insulation over to the drainage tile!!! We will be moving to Maine as my Wife has received a job transfer and after we find a rental, I will be searching for a piece of land to build upon... Thank you!!!

[@actionjack84]

is there no worry of the relatively little bearing (~2") of the actual CIP concrete on the bearing ledge of the stem wall?

[@AndrewMarsch]

can you still dowel a slab to the footing with the insulation in between as shown here in every scenario?

[@BrianBaldridgeC]

4:06 … you are calling out cement board over the foundation insulation, and then Delta-MS Foundation Drain Mat over the cement board. What type of cement board are you using? How is it attached to the foundation? And are you applying anything to it, to seal it, prior to installing the drain mat?

[@pcatful]

How do you do an interior bearing wall with the slab & insulation on grade? Is it just like the exterior wall?

[@cottagekeeper]

Could you address how to install the Vapor Barrier when the contractor has used a header block that the 4" slab pours into?

[@38snipshow]

Any more icf videos on the horizon? Love your videos

[@imn9466]

Thanking you for such a great explanation of maximum cases.

[@DavidJones-pn6jm]

What about an ICF build? Particularly where the wall joins the stem wall or floor?

[@bayareabrit]

Thanks for this very useful video. My plans have R5 1" rigid insulation called out around the edge of the slab here in California. I was wondering, is it best to install these insulation boards inside the forms before pouring the concrete or to install them afterwards?

[@ASIRIDesigns]

Thanks for watching! In answer to your question, if the rigid insulation is to be installed on the exterior of the slab assembly, it's best to install it after the concrete has been poured and cured, as the waterproofing/damp proofing will need to be applied to the concrete prior to the installation of the rigid insulation (unless you're using ICFs).

[@vincentpereira8416]

What is best for warmer weather countries

[@stupendas101]

There are two types of climate zones: One for growing and the scale goes from zone 1 as the coldest and 10 as the warmest. Then there is the building climate zones which is opposite, ie zone 1 is very hot and humid and zone 10 being frigid cold, so now this makes sense the colder the climate the more insulation you need as long as you use the right climate zone scale

[@georgeacenas-bx9bw]

Slab on grade great lessons and thought provoking. Thermal bridging, potential wicking not to mention water and frost heave all seen important!

[@peterhun3185]

When vapor barrier is placed under the perimeter footing, the friction between concrete and soil is compromised. How do you handle this?

[@metal_mo]

How would the detail at 6:15 change at garage door openings?

[@SnakeHandler-g7u]

In option 1, would it be harmful to do a vapor barrier above and below the insulation in the slab? I would think it would last longer if it never gets wet from ground contact, and it's cheap insurance.

[@ViraShumeyko]

Asiri, do you mean clean stone when you call out “crushed stone”?

[@صحتمندلوگ-صحتمندمعاشرہ]

Very informative video. I have two questions: 1) Does the slab not need 2" to rest upon? A standard frost wall is 8" thick. 2" for the slab and 6" for the sill plate. 2) If the rigid insulation is placed at further outwards to leave 2" resting space for the slab, it will cut into the sill plate area. Will it not diminish the weight-bearing strength of the frost wall?

[@harolddouglas4057]

What software are you using for this demonstration?

[@ASIRIDesigns]

Drawings where made in AutoCAD and exported to a PDF, and I used a PDF viewer to sketch over the details on the iPad.

[@danielouellette7434]

What would your recomendation be if you start with an on ground engineered footing 24" x 10" with 4 rebar and ICF walls ?

[@trbopwr79]

What about cmu foundations with header block?

[@samsultana315]

Are footings necessary for a slab on grade?

[@machickman4041]

Hello, do you design plans for post frame buildings with these type of details? I have been looking for someone to draw the plans of my future home for sometime.

[@ASIRIDesigns]

Hello there! Most of my client work is consulting these days for building issues, but I do take on a small limited amount of high performance home projects per year. Feel free to reach out on the website and we can see if it's a good fit.

[@lyndleshelby6291]

Also, post frame on a basement! NO ONE (that I've found on KZbin) is putting out detailed videos about this type of design!

[@liberaljoe]

I lived in a slab on grade house for 3 years. I much prefer a basement. Lots of storage, great spot for the utilities and a better built house overall. And isn't the standard a Frost Protected Shallow Foundation? The Scandinavians developed that didn't they?

[@peterxyz3541]

Thanks. I’m following for useful info. I’m researching a home build

[@tristatehomesllc599]

Have you ever seen water on a mono slab wick so much that it would pool? Is this possible?

[@cottagekeeper]

Thank you! Trying to implement your ideas and I’m being told in Virginia that the code will not permit 6” of crushed stone that the max is 4” - will this be sufficient in your professional opinion?

[@JE-bd3wu]

for option 5 the monolithic turn down slab thats insulated on the interior. how would you install the insulation if the ground isnt uniform especially if the foundation wall has to be deeper, say 3, 4 or 5 ft? sometimes there isnt the room to put insulation on the outside.

[@franklinmade396]

Hi there. Thanks for the great content. Do you have a recommended detail for under a door opening? How do you insulate the slab at the door opening?

[@ASIRIDesigns]

Thanks so much for watching! There are several strategies that you can use underneath door transitions. A lot of people (including myself) like to use an aluminum or stainless pan to provide the transition and to protect the foam below. Fine Homebuilding and Green Building Advisor have some great details if you search "insulated slab exterior door transitions".

[@pacodefrancis7235]

@@ASIRIDesignsthanks I’ll need to look that up. I have two doors I need to detail that I was concerned about. Does this work for garage doors as well? This is in my shop (12x12 garage doors for skid steer and mini ex)

[@chrismartin-q5y]

I have tried to design this with an engineer, and we found that your anchor bolts being used in the concrete I believe three and three-quarter inch of concrete on each side, which means you need a full 8 inch concrete wall for the anchors to work. By using the phone, you’ve narrowed it to 6 inches. Have you ever ran into this or checked on it with a new engineer?

[@johnnyboyO311]

Using a monolithic slab in climate zone 2. Which one of your insulation technique is best? Thank you for your time.

[@jorgemarien5140]

I second that. I’m working on climate zone 2 as well and the water table is very high. These videos are great, but with most of them and other similar channels the climate zone or region of the project, type of soils, and other localized info seems to be missing. I find that it is always good to follow up with the local contractors, soils and structural engineers for more specific construction methods that may apply to your project. Thanks for bringing it up @johnnyboyo311. Thank you for the valuable content asiridesigns.

[@karenromero1703]

Anybody have any experience with glavel, a glass foam gravel. Could you Eliminate the foam board and just use glavel, then vapor barrier and then the concrete slab?

[@ASIRIDesigns]

This is a really interesting concept. You should ask Steve Baczek Architect, he has experience with Glavel.

[@pacodefrancis7235]

It seems like the majority of new homes here in the Northeast are increasingly using the frost protected shallow foundation, reviewed in the last detail because the concrete and excavation costs are a small FRACTION of the first couple designs, yet it seems like there is no noticeable compromise in performance. Is there a compelling reason to use the first 3-4 assemblies? We’re talking 4-5x more expensive than a FPSF with a continuous foam envelope.

[@patty109109]

I’m in western New York and have never seen a FPSF. I’m guy a regular Joe but I always look at new builds in the area. The obvious problem with it is you don’t get a basement, which for many is a cheap expansion on home size. I use mine constantly.

[@pacodefrancis7235]

@@patty109109 I’m seeing them become more common over the last 5-10 years. Nothing “cheap” about basements though. Cheaper would be addition a bump assertion or a second floor. Pouring a footer, walls then a floor (joists) system is a LOT more money than framing above grade… a larger garage is how to get extra storage, etc for cheap. I love basements, but they’re more of a luxury.

[@beau5271]

Great video but website is being a pain. Cookie notification and Google add take up half the screen on mobile browser and won’t go away. Do you have similar content for piers? Thanks!

[@ASIRIDesigns]

Thanks for watching! Sorry to hear the website is giving you trouble (still figuring out how to optimize for mobile). There is some limited content on pier foundations, is there anything specific that you would like to see? Cheers!

[@beau5271]

@@ASIRIDesigns exact same type of video as this but for raise floor installations. I’m slowly getting through all the BSC videos/website but will still seek consultation when the time comes. Your videos are really great, more detailed. So I will reach out for appointment to check my work when build time comes. Bit of a curve ball question for you, don’t really need to worry about cold where I live in Queensland, Australia. What’s better, break continuous thermal barrier to maintain slab thermal sink with shaded eves or maintain building science principals to retain environmental control but with greater cooling requirements provided continuous WRB is maintained. Just don’t have the slab sucking out heat..

[@ASIRIDesigns]

@@beau5271 I will definitely add it to my video list, thank you for the suggestion. With regard to your question about slabs, I would air on the side of continuous water and air control strategies. These are always more important than thermal considerations...Water kills buildings really quickly, followed by air leakage. Control those and you will have a long lasting building. A little bit of an energy penalty in a warmer climate will be okay, it's much less desirable or comfortable in temperate and cold climates.

[@briant7067]

Thank you for sharing! Great information!

[@builtra]

Do you use Vectorworks ?

[@ASIRIDesigns]

I do not - my workflow is primarily in AutoCAD and Sketchup.

[@tsaipod]

LOVE THIS!

[@richemmrich1858]

VERY GOOD explanation. Please kill the music.

[@SteveV1960]

Video would have been much better without the music.

[@justincrasi4638]

in the NE we often see slab on grade for garages only. do you feel that a perimeter drain is necessary for a detached garage, which has soil on both sides to counteract hydrostatic pressure? Obviously it's better but is it necessary? perhaps the perimeter drain could be under the slab on the interior side of the wall to prevent hydrostatic pressure build up under the slab, bc water can rise as well. If so it would be less expensive to simply do a trench concrete footing and stem wall, without having to further excavate and water proof. Simply, would this actually work long term without major consequence and save clients money?

[@ASIRIDesigns]

I would say if it's a detached unheated/unconditioned garage on a site with good grading and drainage, you could probably omit it, but you'd need to address it on a case by case basis. If your clients store expensive cars in their detached garages or any moisture sensitive items (as many people use their garages as ancillary storage), a perimeter drain is a good idea just to avoid any potential liability.

[@justincrasi4638]

@@ASIRIDesigns Thanks appreciate the response!

[@jeffvandagrif]

Very similar to a big walk in freezer slab.

[@thomasschafer7268]

😅😅 toller Beitrag. Aber so baut man schon 25 Jahre. Noch besser ist eine sogenannte Schwedenplatte!!.👍👍🇩🇪

[@paulgilliland2992]

Those last few details are just ridiculously expensive to build . So easy to show a Vb under the slab and footing.

[@cathalsurfs]

Great info. Vocal fry is a bit distracting. Soz.

[@907shaun]

Great video

[@ASIRIDesigns]

Thanks for watching! Cheers!

[@907shaun]

@@ASIRIDesigns Little back story. I’m A bricklayer from England but moved to Fairbanks Alaska and I’m starting doing my own construction here I’m finding lots of new techniques not only with differences in uk to USA but also arctic cold climate construction I’m going g to be pouring my slab for my own home extension this may 22x36 shop with second floor living area If using 2x6 frame would I make the stem wall 4” plus 2” insulation so my 6” baseplate would cover the insulation?? I was thinking of building my stem wall in 4” or 6” concrete blocks

[@ralphjessee2688]

Nice content and narration. (The music is a waste.)

[@pcatful]

Your exterior wall concrete curb is not wide enough to please the structural engineer.

[@SweSuf]

The background music was really annoying...

[@chillrockit]

You’re welcome to go watch a different channel then. 😁

[@Mr.Monta77]

It could have been lower for sure.

[@bobangmereier4311]

Who is the narrator?

[@McJiver]

The real question here is why are we insulating the concrete on the bottom at all? Why not just use an appropriate rigid insulation above? Seems likely we are spending extra time and money coddling concrete. Concrete was never developed for this kind of use and I can't help but think the generations of builders long gone would look at this construction as madness.

[@timothykeith1367]

Insulation on top of the concrete can cause condensation with the cold concrete, which can produce mold.

[@pappaG2000]

Sounds great, and all this sounds like a Commercial Cost Residential Quality house. Which to me, living in Zone 5a, and the push for the IECC to enforce ASHRAE 90.1-2019 and some states pushing more strict compliance. A tiny home even what you are explaining of maybe 2,000sf will cost $600.00 per sf. 1.2 million for a house is just wasteful since a house with today's materials will never last 200 years and materials today are Junk Quality comparing to Quality and craftsmanship of the 30s 40s 50s. Especially when average wages were approximately $13,000 and a house cost $42,000 of comparable size, when a person's avg wage is $70,000 so if the inflation was the same, only those making $300,000 could build that house... 🤔

[@ChrisMaveric]

Now... "pay" for all of these details and say a prayer in hopes the installers (subs) each do their portion correctly.... not likely.

[@joeschmoe1301]

Music is annoying and distracting.

[@tomaskey6844]

STOP WITH THE BACKGROUND MUSIC!

[@mr.y7821]

This is wrong. This is old way how we built in scandinavia. There is a much much better way and correct way.

[@frostycools1315]

the first two are very poor designed slab insulation would not meet min codes in Canada

[@ASIRIDesigns]

Not everyone lives in a cold climate...

[@frostycools1315]

@@ASIRIDesigns what does that have to do with the poor design ? we insulate for heat and for cold try too keep up