This is valuable information. A well-planned basement build-out can add very usable space to your home. Another way of obtaining minimal thermal break under the sole plate on a basement slab is to staple two layers of roofing felt. If you have concerns about water getting in, and you don't want to trap it between the sole plate and concrete wall, you can elevate the sole plate under the studs by screwing plastic shims onto the bottom of the sole plate before installing it. Then compress backer rod into the air space between the floor and the sole plate. If you need to remove that backer rod to let water out and air in, you can. Then when things are dried out, tuck it back in. Of course, the best way to go is to ensure that you don't have water intrusion to begin with. But not everyone has that option and budget.
The combination of rigid foam, spray foam, and various diameters of backer rod will allow you to get the wall assembly air tight, if you put the time in and pay attention to detail.
If you don't mind a completely uninformed opinion, glavel looks like crushed stone with some insulating factor. Under a slab it seems like it would work to hold temperature some (@R1.7/inch). Water isn't going to creep up the gravel, but vapor will and will condense on the coldest surface it can find. This could be the bottom of the slab. From there capillary action and a warmer or drier surface will pull it up into the basement. This is why you need (again, I know nothing) a vapor barrier under the slab. ps - Corrections welcome!
On a single level home with a concrete slab with load bearing walls can you use the polyiso as you did here in this video? If no what would you recommend
On a new build they are very likely putting the ridgid insulation under the cement slab. I believe it's best practice in many places and a code requirement in some locations.
This is valuable information. A well-planned basement build-out can add very usable space to your home. Another way of obtaining minimal thermal break under the sole plate on a basement slab is to staple two layers of roofing felt. If you have concerns about water getting in, and you don't want to trap it between the sole plate and concrete wall, you can elevate the sole plate under the studs by screwing plastic shims onto the bottom of the sole plate before installing it. Then compress backer rod into the air space between the floor and the sole plate. If you need to remove that backer rod to let water out and air in, you can. Then when things are dried out, tuck it back in. Of course, the best way to go is to ensure that you don't have water intrusion to begin with. But not everyone has that option and budget.
Great point about the adhesive Steve, it will damage the ridgid foam board. Another informative video , love watching and learning
Thank you for the videos Steve! What was the finished floor details of this basement?
great info about finishing out a basement / lower level.
How do you A+ a basement window install in a poured concrete wall?
The combination of rigid foam, spray foam, and various diameters of backer rod will allow you to get the wall assembly air tight, if you put the time in and pay attention to detail.
Why not make the polyiso under the wood a bit wider to lift the drywall off the slab ? This would be covered up by baseboard.
Thanks Steve!!! 🔥🔥🔥 Would the use of an appropriately thick layer of GLAVEL suffice to reduce water migration up to the concrete slab?
If you don't mind a completely uninformed opinion, glavel looks like crushed stone with some insulating factor. Under a slab it seems like it would work to hold temperature some (@R1.7/inch). Water isn't going to creep up the gravel, but vapor will and will condense on the coldest surface it can find. This could be the bottom of the slab. From there capillary action and a warmer or drier surface will pull it up into the basement. This is why you need (again, I know nothing) a vapor barrier under the slab.
ps - Corrections welcome!
On a single level home with a concrete slab with load bearing walls can you use the polyiso as you did here in this video? If no what would you recommend
On a renovation, do you worry that you'll get condensation between the concrete foundation wall and the polyiso board?
I think the aluminum backing is a vapor barrier
So Steve why don’t you use this thermal break on new builds in basement walls>
On a new build they are very likely putting the ridgid insulation under the cement slab. I believe it's best practice in many places and a code requirement in some locations.
Also on a new build (if done right), they'll put a vapor barrier under the slab. That's probably also a code requirement in some locations.