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How To Install Rigid Foam Insulation on Concrete

41K views 9 replies 3 participants last post by  earthad1 
#1 · (Edited)
Hi everyone,

I've been looking for directions on how to install 2" Rigid foam insulation to the exterior walls of my foundation in order for Perma Crete to warranty work I want to hire them for to seal up a crack I have in my foundation (they will not warranty their work unless I insulate first).


I found the below article and was wondering if anyone with experience in this sort of thing has anything to add, or objections to the method proposed below. I did notice that it does not tell me how deep I should insulate and I don't quite understand why I need to use these "self tapping concrete screws with washers". I thought you just needed to glue these boards on with a good quality adhesive. Needless to say, I'm a little nervous with the idea of adding holes in the concrete since I have no experience with this stuff.

Also, when filling the hole back up, I was wondering if its a good idea to make a slight slope going away from the foundation and putting down some nice thick plastic as was proposed in this thread: http://www.diychatroom.com/f19/opinions-wanted-foundation-trench-sketch-39655/ I figure since I'm down there I may as well do everything I can to divert water...

I'm assuming I can skip steps 6 and 7 as they seem to apply solely for interior applications.

As usual, any assistance is appreciated.

Thanks all!!! :thumbup:




How To Install Rigid Foam Insulation on Concrete

Things You’ll Need:


  • Hand saw or cut-out saw Tape measure Marking instrument, such as a pencil Hammer Self-tapping concrete screws and washers Fiberglass tape Adhesive Furring strips Concrete water sealer
Step1
Prep the concrete wall before installing the rigid First, wash the wall with water and a mild detergent. Next, cover any cracks in the wall with a recommended crack repair product. If the wall has not been water seal-treated, this will need to be done prior to installing insulation.

Step2
Measure the space where the rigid foam insulation will be installed. Once the measurements have been recorded, start measuring the rigid foam insulation. Mark with a pencil or marker where cuts will be made. For long lines, snap out a line using a chalk box. Use either a hand saw or reciprocating saw to cut the rigid foam insulation.

Step3
For exterior foundation installations, water proofing will be applied to the concrete before continuing. Install the insulation after the sealer has dried. Using a recommended adhesive, apply it only to an area large enough that glue will not dry before completing entire wall.

Step4
Place rigid foam panels up to glue and set in place. When a complete wall is insulated with rigid foam insulation, use a tape measure and mark a line every 24 inches down the length of the insulated wall. At each line made horizontally across the wall, measure up every 24 inches and place more marks the height of wall. These marks are where to use self tapping concrete screws with washers to screw the foam into place.

Step5
Spread the screws 24 inches apart vertically and horizontally the entire wall; protect the screws and washers from the elements by placing fiberglass tape over them. Any exposed rigid foam insulation that sits six inches below grade and up on exterior wall applications should be covered with metal, cement board, or stucco.

Step6
During interior installation of rigid foam insulation, apply a waterproofing to the exterior of the concrete walls if possible. If installing gypsum board, run furring strips horizontally every 24 inches. Use self drilling concrete screws to install furring directly to wall. Furring strips should be same thickness as the rigid foam insulation being installed. If there will be no gypsum board or wood walls, do not install furring strips.

Step7
Cut the rigid foam insulation to fit between the furring strips. If furring isn't present, cut and install the rigid foam as in step two. Apply adhesive to the interior of the wall between the furring and glue the rigid foam insulation. Run self-tapping concrete screws down the center and every 24 inches of the rigid foam insulation to hold in place. Finally, place gypsum board or wood walls over the wall and screw or nail into the furring strips.
 
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#2 ·
you call'd the wrong guys,,, have it either seal'd w/( silicone/polysulfide ) OR epoxy inject'd by someone who knows what they're doing.

most ( not all ) p-creters know as much about conc repair as my dentist :laughing: he fills cavities but is dumb as a box of rocks w/driveway-pool apron-lanai-sidewalk,,, there absolutely NO reason for that method 'cept they don't know any different, are repeating what some dumbbell back at corp said, OR are guessin',,, then again, they pay their $$$ looking for quik profits & don't really bother to educate themselves further,,, IF your crk extends down to the footer, excavation'll be nec.

guys like that give us ALL mechanics a poor name as we're all painted w/the same brush,,, icri.org would be a good place to look ( international concrete repair institute ).
 
#3 · (Edited)
you call'd the wrong guys,,, have it either seal'd w/( silicone/polysulfide ) OR epoxy inject'd by someone who knows what they're doing.

most ( not all ) p-creters know as much about conc repair as my dentist :laughing: he fills cavities but is dumb as a box of rocks w/driveway-pool apron-lanai-sidewalk,,, there absolutely NO reason for that method 'cept they don't know any different, are repeating what some dumbbell back at corp said, OR are guessin',,, then again, they pay their $$$ looking for quik profits & don't really bother to educate themselves further,,, IF your crk extends down to the footer, excavation'll be nec.

guys like that give us ALL mechanics a poor name as we're all painted w/the same brush,,, icri.org would be a good place to look ( international concrete repair institute ).
Thanks for your reply. I am still having the crack injected as you had suggested in another post, and not necessarily by Perma-Crete. I figured if they won't warranty the work because of lack of insulation, others won't as well (though I may be completely off the mark on that).

What I'm saying is that I want to install exterior insulation around the entire house on top of fixing the crack and any other issues.

I have noticed very fine cracks at other places and I don't know if this is normal (house is 32 years old) or if its something that can get worse. So I wanted to dig down (problem is, I don't know how far down I need to dig, which was one of my questions), seal up any little cracks, apply a watertight seal paint, put the 2" rigid insulation, fill the hole back up and apply some nice thick plastic graded away from the house.

So are you saying I should not waste my time adding exterior insulation around the entire house?

I've gone to icri.org as you suggested last time. I click on the "contact ICRI" but I don't see an email address.

So I checked the "Chapters" section and the only chapter in Canada in in Quebec. I'm going to look in the phone book and see if any of the companies around here are members.Thanks again.

EDIT: I think I found my answer:

as per http://www.engext.ksu.edu/henergy/envelope/basement.asp

How deep should foundation insulation extend below grade?
Insulation should extend all the way to the footing. A heated basement will always lose heat through its walls, no matter how deep they are.

Although heat loss to the soil near the bottom of the wall is not great, heat is conducted up the wall to colder soil near the surface. Insulating the entire wall reduces this bypass heat loss.
Also, keep in mind that the cost of the additional insulation is relatively small compared to the cost of framing and finishing the wall

but then, a wiki article, as per
http://en.wikipedia.org/wiki/Installing_building_insulation says :
Insulating exterior of foundation

Ideally, a home should have poured concrete walls, waterproofing, and 2-inch rigid foam panels. Complete retrofit foundation insulation may be prohibitively expensive. Since most of the heat loss from a foundation occurs where the foundation is above grade and exposed, you can partially insulate the foundation wall and still have good results:

So Basically, I guess I can insulate just below the frost line and I should be ok :huh:
 
#4 ·
epoxy crk injection's another of those specialty items,,, there are companies who do both but its rare,,, 'insulation' is immaterial to any warranty/guarantee as you'll find out when you have an experienced mechanic do the work,,, we'd pick hydrophyllic polyurethane.

you post'd the fnd's conc,,, you could use const adhesive & stick on the insulation board but i've never done it NOR have i seen it done,,, whatever adhesive you use ( maybe even acrylic latex caulk ), just be sure it won'd dissolve the board,,, wouldn't you then have to have protection for the insulation board, too ? ? ?

those very fine crks're probably not an issue but dig a bit & see what that reveals,,, any water in the bsmt othern'n from the lge crk ? ? ?

(thoroseal/drylok) mtls're good for positive-side wtr-proofing but not negative-side (inside) :no: our code calls for 5' leader drains from downspouts but the (farther-further) you can direct water from the house the better.
 
#5 · (Edited)
epoxy crk injection's another of those specialty items,,, there are companies who do both but its rare,,, 'insulation' is immaterial to any warranty/guarantee as you'll find out when you have an experienced mechanic do the work,,, we'd pick hydrophyllic polyurethane.

K, thats really good to know... Thank you. So hydrophyllic polyurethane seems to be the way to go. I've got that written down :thumbsup:

you post'd the fnd's conc,,, you could use const adhesive & stick on the insulation board but i've never done it NOR have i seen it done,,, whatever adhesive you use ( maybe even acrylic latex caulk ), just be sure it won'd dissolve the board,,, wouldn't you then have to have protection for the insulation board, too ? ? ?

They sell adhesives especially for this type of application, and yes, anything above grade needs to be protected. They recommend metal, cement board, or stucco

those very fine crks're probably not an issue but dig a bit & see what that reveals,,, any water in the bsmt othern'n from the lge crk ? ? ?

No water seepage that I can tell (its a 4 level split home so I have a 2-floor basement type of pour). No water on the floor/under carpet. No stains of any drywall or anything. but, since that large crack, I've been super paranoid of having any other issues so any crack to me is concerning :(.

The only thing I've noticed, and it may be completely separate, or has always been like that, is that is "seems" that the drywall joints on the 3rd level have cracked as there is a fine line in the drywall running horizontal across the 2 rooms and only on the exterior walls. I have a ledge that runs alongside the exterior walls
and the line is about a foot below grade. But like I said, that could have always been there and never noticed. The builders or whoever may simply done a poor job taping the joints, but since I found that crack, my home has been under s microscope. LOL.

The large crack starts straight, then curves and end at the door frame (almost looks like the letter "C"). There is a little water that runs down the crack, then down the door frame, and drips onto the carpet ( a damp circle maybe a foot in diameter).


(thoroseal/drylok) mtls're good for positive-side wtr-proofing but not negative-side (inside) :no: our code calls for 5' leader drains from downspouts but the (farther-further) you can direct water from the house the better.

"thoroseal/drylok) mtls're" - Sorry, I'm not sure what you mean by this. Is this a type of waterproofing sealant to be applied to the foundation? Is this the stuff that crystalizes and bonds to the foundation? similar to I think it was called xypex?

My downspouts are 72" long on all 3 drains so the water runs well away from the house. I have a grading issue with my neighbor so I'm going to run drains at the beginning of my property that drains out to the road.

.....
 
#6 ·
"thoroseal/drylok are cementitious materials applied to surfaces to prevent wtr intrusion,,, if you know xypex, that's a far superior product impo as it IS a penetrating (crystalline) liquid,,, thoro/drylock's are surface bonding coatings - again, impo.

sounds as if you're on top of the situation & much (further/farther) ahead of the p-crete guys [ which isn't difficult for the majority of 'em :laughing: ]

{ wish i knew the difference 'tween further & farther :eek: }
 
#7 ·
"thoroseal/drylok are cementitious materials applied to surfaces to prevent wtr intrusion,,, if you know xypex, that's a far superior product impo as it IS a penetrating (crystalline) liquid,,, thoro/drylock's are surface bonding coatings - again, impo.

sounds as if you're on top of the situation & much (further/farther) ahead of the p-crete guys [ which isn't difficult for the majority of 'em :laughing: ]

{ wish i knew the difference 'tween further & farther :eek: }
:laughing: Thanks for the confidence. I'm hoping once I eliminate the drainage issues on the property, the rest will fall into place. I'm attempting to be proactive rather than reactive, which is the reasoning behind adding the 2" exterior insulation.

Thanks again for all your help/input. especially on the hydrophyllic polyurethane + xypex recommendations
 
#8 ·
go suck an egg :laughing: sorry - meant to post ' go & leak no mo' ! ! ! ' :huh:

there's a chance those clowns knew their stuff but, bas'd on your post, i wouldn't bet even yomama's $ on it - dick's another story :yes: 'cause he's an engineerer & has got bucks :thumbup:

seriously, post what happens when its all done ! best !
 
#9 ·
go suck an egg :laughing: sorry - meant to post ' go & leak no mo' ! ! ! ' :huh:

there's a chance those clowns knew their stuff but, bas'd on your post, i wouldn't bet even yomama's $ on it - dick's another story :yes: 'cause he's an engineerer & has got bucks :thumbup:

seriously, post what happens when its all done ! best !

Hey, I was going to stay out of this one, looked like you have it handled!:whistling2::thumbsup:

I am glad you stated NOT to use Drylock or Thoroseal on the inside though. I hope more people can read that!:thumbup:
 
#10 ·
:thumbsup:

Last December, I ended up excavating the entrance walls to the footer and having the crack injected and entire structure wrapped with a waterproof membrane, got a concrete floor poured w/ a drain to the weeping tile.

This summer, I Installed 2 corrugated drains /w sock with 8" of crush underneath. One, which divide my property and my neighbors property and drains to the road and into the woods. The other runs parallel with the entrance wall and dumps into the main drain going into the woods.

This weeked, I installed a second drain on the other side of the wall and and regraded the entire area.

I'll post photos.

The basement is dry as a bone! Absolutely not a drop of water, even after a few rainy nights of 40mm or more of rain :thumbup:
 
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