My house is on a slab and id like to add slab edge insulation around the footer of the house and garage. I have 2inch XPS that I ripped down with a 45 degree angle on top. I bent aluminum coil that I plan to cover the XPS with that will tuck under my siding J channel and also bends to cover the bottom edge of the XPS. Im wondering how I should attach the XPS to the edge of the slab and then how I should attach the aluminum to the XPS. Anything else I should consider while doing this? Thanks!
Installing slab edge insulation to existing slab
- Thread starter derekeh
- Start date
AC-WC
Well-known member
I would recommend predrill and use tap cons for the foam. I tried using construction glue on some automatic crawl space vents and it only lasted 3 yrs
I ended up going back and using some tap cons and straight brackets like you would on frames.
I ended up going back and using some tap cons and straight brackets like you would on frames.What did you cover your foam with and how did you attach it to the foam?I would recommend predrill and use tap cons for the foam. I tried using construction glue on some automatic crawl space vents and it only lasted 3 yrs
AC-WC
Well-known member
Just to clarify-I have not used foam on my concrete foundation. I have used it on ceiling install in my garage.
Recommend you use the large plastic washers so the tapcons don't pull through the foam. Once the washer starts to squish stop driving the screw!
For the sheet metal you may get stuck with using adhesive. Nails will not retain into the foam, not sure how well screws will grip into the foam to secure the metal.
Maybe install tapcons through sheet metal and foam?? Downside is you would see all the screws and likely need to paint them to color match.
Recommend you use the large plastic washers so the tapcons don't pull through the foam. Once the washer starts to squish stop driving the screw!
For the sheet metal you may get stuck with using adhesive. Nails will not retain into the foam, not sure how well screws will grip into the foam to secure the metal.
Maybe install tapcons through sheet metal and foam?? Downside is you would see all the screws and likely need to paint them to color match.
AC-WC
Well-known member
Here's the washers-I used these on both the ceiling foam and plastic foundation seal on my barn basement.
https://www.menards.com/main/buildi...36701/p-3289655538506206-c-5776.htm?exp=false
Not sure what the best adhesive would be for outdoor. I know it's not Liquid Nails!
Try looking for this type of adhesive. It sounds like what you're looking for for sheet metal to foam.
https://www.menards.com/main/buildi...36701/p-3289655538506206-c-5776.htm?exp=false
Not sure what the best adhesive would be for outdoor. I know it's not Liquid Nails!
Try looking for this type of adhesive. It sounds like what you're looking for for sheet metal to foam.
yatg
Well-known member
PLfoamboard sounds like plain old latex caulk with a drop of blue dye.
Admittedly I've never glued XPS to alum, but I would do a test with PL Premium and see what happens.
Even loctite says its OK to use on XPS
Admittedly I've never glued XPS to alum, but I would do a test with PL Premium and see what happens.
Even loctite says its OK to use on XPS
Firebrick43
Well-known member
The aluminum trim coil will corrode very quickly in contact with the ground.
They make panels with synthetic stucco already applied to the face of them for this purpose or you can buy synthetic stucco and fiberglass net and apply it to the foam yourself.
For the flashing, Pop the bottom edge of the vinyl siding out from the starter piece. Measure where the starter piece is and remove the nails from it. Buy or form aluminum z flashing to go ever just a few inches of the foam and slip it under the tyvek and place a few nails to hold it in place. Reinstall the starter strip in the same location and Re nail thru it and the top leg of the z flashing. Re snap in the bottom edge of the vinyl siding. Warning, if your siding is 15 years old or older I wouldn’t touch it or your likely to crack a significant amount of it.
They make panels with synthetic stucco already applied to the face of them for this purpose or you can buy synthetic stucco and fiberglass net and apply it to the foam yourself.
For the flashing, Pop the bottom edge of the vinyl siding out from the starter piece. Measure where the starter piece is and remove the nails from it. Buy or form aluminum z flashing to go ever just a few inches of the foam and slip it under the tyvek and place a few nails to hold it in place. Reinstall the starter strip in the same location and Re nail thru it and the top leg of the z flashing. Re snap in the bottom edge of the vinyl siding. Warning, if your siding is 15 years old or older I wouldn’t touch it or your likely to crack a significant amount of it.
WisJim
Well-known member
I've done something similar a few different ways. First time I glued the foam to the foundation and used a premixed vinyl stucco on the foam, and neither worked well. The glue (and I don't recall what I used, but it was recommended on the label for the use) didn't hold long and the "stucco" was fragile and easily damaged. Later I did another project and used glue on the foam board and then covered it with a grey fiberglass material made for the purpose, and fastened that through the foam into the masonry with tapcons or similar. It is still good after 30 years. When I replace the first foam board and stucco stuff, I got prefinished foam board at Menards, the stuff with a cement stucco or plaster already applied, and it is holding up very well.
kyrbz
Well-known member
I'm using these Plastic-Grip masonry fasteners on a project I'm working on right now. Drill a 5/16" hole and pound them in until the foam slightly compresses. They're about $100 for 250 of them.
Highbeam
Well-known member
I'm using these Plastic-Grip masonry fasteners on a project I'm working on right now. Drill a 5/16" hole and pound them in until the foam slightly compresses. They're about $100 for 250 of them.
When I've poured concrete over foam it stays down. Are you planning some sort of floating floor over the foam?