Protecting exposed slab insulation?

[papp101]

I live in Minneapolis, MN and am building a 24*26 shop with an insulated monolith slab.

2 inch foam underneath and up the sides of the slab, and also covering 6" of cinderblock.

Flashing will attach to the osb sheathing under the tyvek, then come out and break down to provide a trip ledge for the foam.

Question: with about 12-14 inches of exposed xps foam, what would you cover it with for durability?

Stucco eifs with fiber mesh?
Cement backer 1/4" board then stucco eifs system?
Thick sheet metal cladding?

Thank you so much for your input, I've been mulling this over for about 6 months!!

See attached reference document I came across on the Internet.

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[matt_i]

Re: Protecting exposed slabbinsulation.?

That's one thing I really couldnt figure out when looking at a FPSF.

I think the stucco is best, as its already a proven exterior coating. I'm unsure how cement board would hold up outdoors with freeze-thaw cycles, its basically designed to be moisture-unaffected for bathroom apps but I don't think freezing is taken into consideration.

Trim coil would work but I think it would get dented or worn while trimming grass and then look bad, plus it seems like the direct soil contact would also corrode the lower edge over time.

Any thoughts of faux stone, some of those products look pretty realistic these days and install with not much more than a saw and glue.

The FSPF I was looking at for my brother had all of the foam on the inside, it went under the footing and up the diagonal and then all the way under the floor. To avoid this same issue all together. The exterior would then be just traditional exposed concrete.

 

[aaronmn]

Re: Protecting exposed slabbinsulation.?

I have trim coil in Northern MN. It works - no corrosion. Damage to the coil is minimal after 15 years.

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[ConCretin]

Re: Protecting exposed slabbinsulation.?

There are stucco products that can be applied directly over the XPS insulation but I don't think they look great or hold up very well.

A true EIFS system consists of EPS insulation board, a base coat reinforced with fiberglass cloth followed by a top coat. It's durable and looks good but would be pricey. Personally, I like the stone veneer idea but you'd probably need a backer board and would want to overhang your framing to cover the top. Not a cheap solution but it would look great :thumb:

If that's too much trouble, I'd probably opt for the metal over cheap stucco.

 

[Tduby]

Re: Protecting exposed slabbinsulation.?

I was looking at this product if anyone has options
https://www.menards.com/main/buildi...250-c-9532.htm?tid=-707108448038776629&ipos=6

 

[matt_i]

Re: Protecting exposed slabbinsulation.?

That product looks pretty good!

 

[climb.on]

Re: Protecting exposed slabbinsulation.?

I was looking at this product if anyone has options
https://www.menards.com/main/buildi...250-c-9532.htm?tid=-707108448038776629&ipos=6

I used a product like this. I got it from an insulator though and it was way cheaper. Only been down 6 months but I like it so far. You can see the foam on the left and the groundbreaker like product on the right. Not much exposed here, as the apron is getting poured here. I ran short and need to add a piece there. I think my rolls were 24" x 100'. I opted for this over aluminum as I was afraid the aluminum would get dented and beat up looking after a while.

 

[mnwebb]

Re: Protecting exposed slabbinsulation.?

papp101 we're in the same boat, I'm in St.Paul Mn and my garage (https://www.garagejournal.com/forum/showthread.php?t=389630&highlight=mnwebb) is slightly bigger. Hoping to begin next month. I'm also insulating the slab and don't know how far to go. In your posted image the slab isn't insulated underneath like I was planning (see image below). Isn't the purpose of this to keep heat inside of the slab and so you're not heating the ground below?
Just curious on your thoughts and choices.

 

[climb.on]

Re: Protecting exposed slabbinsulation.?

papp101 we're in the same boat, I'm in St.Paul Mn and my garage (https://www.garagejournal.com/forum/showthread.php?t=389630&highlight=mnwebb) is slightly bigger. Hoping to begin next month. I'm also insulating the slab and don't know how far to go. In your posted image the slab isn't insulated underneath like I was planning (see image below). Isn't the purpose of this to keep heat inside of the slab and so you're not heating the ground below?
Just curious on your thoughts and choices.

Papp, if you are heating the building then yes, absolutely insulate under the slab regardless if you are heating the slab or not. Insulation is cheap compared to years and years of added heating costs. Another critical and often neglected area is the vertical edge of the SlB. I recommend 2" under and 2-4" vertical edge. 4" gets a bit tricky to flash and finish though.

 

[papp101]

Wow, what great responses. I really appreciate it!

Yes, I realized after I read this thread I'd posted one without insulation under the slab - we will have 2" XPS underneath the monolith foundation.

 

[ConCretin]

Re: Protecting exposed slabbinsulation.?

The major concern I have with this detail is the impossibility of achieving proper compaction in the slab base material. The inner vertical insulation isn't rigid enough to allow soils to be compacted behind it and any kind of support would be in the way of the concrete placement.

A better detail would be to lay the insulation back at a 45 as shown in the OP's post. The slab base material can be compacted in lifts and then shaped to form the slope. It's a little challenging to lay the insulation in on an angle without voids but it's doable.

It's a good sketch to convey the concept and details of insulating a slab but I wouldn't take it too literally.

 

[Orionrising]

They probably place and compact the pad and then trench the perimeter footing into it.

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[CKS1955]

Somewhere I read that you lose 80% of the heat through the concrete perimeter and only 20% through the concrete floor.

Jay

 

[Orionrising]

Somewhere I read that you lose 80% of the heat through the concrete perimeter and only 20% through the concrete floor.

Jay

depends on the air temperature and what temperature you are heating the building to. Soil stays at 40-50+ below frost depth year round.

I have a split level house with the lower level half in the ground. Downstairs wants to stay about 55 heated or not downstairs in the winter.

my garage well insulated tends to stay in the high 20s- low 30s even when is is below zero out without insulated doors.

 

[Tduby]

Re: Protecting exposed slabbinsulation.?

Papp, if you are heating the building then yes, absolutely insulate under the slab regardless if you are heating the slab or not. Insulation is cheap compared to years and years of added heating costs. Another critical and often neglected area is the vertical edge of the SlB. I recommend 2" under and 2-4" vertical edge. 4" gets a bit tricky to flash and finish though.

Any suggestions on how to finish and flag 4” I want to do 4” on the perimeter but having a hard time figuring out how flash with 2” sticking out past the wall.

 

[climb.on]

Re: Protecting exposed slabbinsulation.?

Any suggestions on how to finish and flag 4” I want to do 4” on the perimeter but having a hard time figuring out how flash with 2” sticking out past the wall.

Do you have a 2x6" wall? Are going to cantilever the wall over the slab? To flash it I would probably have a Z flashing custom made. 4" vertical, 2" horizontal, and 2" vertical. Menards will do this pretty reasonably...among others.

 

[homebuilt burner]

I used a product called Tuff 2 from Menards. It goes on like a plaster/stucco. I did the basement 5 years ago and the woodworking shop 3 years ago and both still look fine. It is paintable. My parents used aluminium trim coil and that still looks good after 7-8 years (as long as you are careful with the string trimmer).

 

[mnwebb]

Climb On are you a vise expert?

 

[bigman68]

Check out this company specifically the Energy Flash product they have:

https://www.eeform.com/about-energyedge

 

[1233user]

I had a local metal shop bend up sheets of stainless steel sheet metal to protect my foundation insulation. It goes at least 8" below grade all the way around. It has been there for several years now, and I am very happy with how it turned out. It is much thicker and more durable than aluminum flashing. It was expensive, but I should never have to worry about it again.

 

[Copymutt]

In all the foundations I've done I never knew they made a product for this application.
I have years of success with Hardiplank cement siding. glued and screwed.
Jim

 

[850xpeps]

In all the foundations I've done I never knew they made a product for this application.

I have years of success with Hardiplank cement siding. glued and screwed.

Jim

Hardie plank is not to touch ground.....

I would just get a roll of tin and attach it to the insulation. It can be placed then the starting row of whatever siding can lap over it.

 

[climb.on]

Climb On are you a vise expert?

Not in any way shape or form. But I do like to restore old arn.

I had a local metal shop bend up sheets of stainless steel sheet metal to protect my foundation insulation. It goes at least 8" below grade all the way around. It has been there for several years now, and I am very happy with how it turned out. It is much thicker and more durable than aluminum flashing. It was expensive, but I should never have to worry about it again.

It doesn't get any better than this. Sweet.

 

[Tduby]

I had a local metal shop bend up sheets of stainless steel sheet metal to protect my foundation insulation. It goes at least 8" below grade all the way around. It has been there for several years now, and I am very happy with how it turned out. It is much thicker and more durable than aluminum flashing. It was expensive, but I should never have to worry about it again.

That’s damn sweet but my garage will be 36X80 I hate to think what that would cost

 

[bruincounselor]

I used a sticky glass mesh and stucco directly on the foam on the house a few years ago and it's held up everywhere I didn't touch it with the weed wacker. On my garage last summer I hung the walls over the perimeter insulation and ran a ring of two foot tall strips of green plywood to earth level. The siding covers all but an inch of it. I get lots of comments on how that detail turned out. No termites here.

 

[nmk_61802]

Re: Protecting exposed slabbinsulation.?

I was looking at this product if anyone has options
https://www.menards.com/main/buildi...250-c-9532.htm?tid=-707108448038776629&ipos=6

Menards also offers an Aggregate covered panel that could be used on the exposed portion:

https://www.menards.com/main/buildi...6794-c-9532.htm?tid=403693358944593329&ipos=5

 

[mnwebb]

papp101 what did you end up doing? How did you tie it all together? I just coated my exterior cinderblock with waterproofing and am trying to decide on a dimpled board or just 2" insulation. Also still trying to figure out the exposed parts and drip edge.
Any idea gladly welcomed!
thx - Wilson

 

[papp101]

Hey Wilson! Actually just had my slab poured last week, so haven't coated it yet.

Was going to go with Tuff II coating from Menards as I have about 18" exposed, but then purchased a more basic product:

Foundation Insulation Coating Cement - 50 lb at Menards https://www.menards.com/main/p-1444445320876.htm

I want a stucco like finish, so will be able to get that with this and it's less expensive. Also, I feel this will be easier to patch in the future without having to buy an 70.00 bucket.

Haven't applied it yet though, might get to it this weekend! Attached is a pic of the poured slab and my boy playing soccer with Grammie. We poured the curb separately and just slid the forms up for the outside wall form. I haven't taken them off yet, so that's the wood sides you see. The foam is underneath it and was in place for the pour.

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[mnwebb]

Looking good papp101!

You don't think that the insulation will still be punctured easily with just a thin coat of that product on top of it? Are going to extend your insulation horizontally on the perimeter as well?

-W

 

[gnpenning]

In my part of the country many are using metal ribbed roofing that has a rusty patina. Some doing the whole wall, others doing a wainscoat . Either old used metal, buying new that has been aged or buying new a aging themselves. Depending on the look you are going for will depend on if this would be a good option.

 

[maxpat82]

I'll be doing cement board and stucco on mine (2' tall on a 28'x44' garage)

 

[papp101]

Which cement board? The 1/2 thick stuff with mesh built in or the 1/4" hardibacker stuff?

Thanks!

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[maxpat82]

the lightweight concrete pannel 1/2....yes the stuff with the mesh built in.

whatever in that style.
It's mainly just to give it a firm backer for the stucco.
If you kick it, the cement board won't deflet as much as the XPS and won't crack the stucco.

 

[papp101]

Agreed, I have been thinking a lot about putting that over the foam first.

I found a few videos showing the eifs durability, makes me on the fence about it.

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[papp101]

FYI all, I used a foundation coating cement with stucco steel corners on mine. Came out ok. Not bullet proof, but not bad and patchable. Here's a few pics of how it came out.

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[TLCObsession]

I have done several projects with smooth Hardi. It has held up great. Some cases were factory pre-finished, others we painted before install. No rot, no cracks, no denting and the weed whackers don't hurt it much.

 

[tjm129]

Re: Protecting exposed slabbinsulation.?

I used this around my garage foundation, was easy to work with, and fairly cost effective. looks great too.

TJ

Menards also offers an Aggregate covered panel that could be used on the exposed portion:

https://www.menards.com/main/buildi...6794-c-9532.htm?tid=403693358944593329&ipos=5

 

[vision8]

I scouted our Craigslist and found the metal cutouts from a man door manufacture so panels were 2 feet by 3 feet from exterior metal doors . Used a small metal brake to bend a 2" lip to over hang the foam . So they go 18" below grade to protect the foam from UV and lawn mower desruction.

 

[markushofer27]

I've seen guys use fiberglass sheet around here on shops although I didn't care for the look too much.

 

[6768rogues]

I would put the foam vertically down to below the frost depth in your area. I have seen buildings not built that way where frost around the building crept under the building and heaved the floor.