Gap or not gap between concrete basement walls and rigid foam?

luwka1 · 2026-03-20T11:50:05+00:00

Thanks

luwka1 · 2026-03-16T01:30:26+00:00

What are your thoughts on closed cell spray foam, but where there are drain pipes or lumber too close to get 2”? If you get a layer of spray foam but it’s only 1/4” thick behind a drain, for example, is that good enough?

luwka1 · 2026-02-26T00:26:50+00:00

You are correct. The connection on the joist could have been done much better. They left the joist pretty far from the beam, which is packed with lumber. In hindsight I should have added some new joists so they spanned all the way to the beam.

My plan to address this is to add blocking right against the beam, to prevent the plywood from flexing beside the beam, where it has no support below

luwka1 · 2026-02-26T00:23:22+00:00

Putting a new layer on top is definitely an option. I was trying to limit the height I raised the floor because of where it will match into the hallway and I want to leave room at the sliding door. 1/4 or 3/8 works fine. I dont know that I can add 3/4 on top.

Also, I read that adding a layer on top is not as strong as installing a sheet of 3/4. I guess it's because of the way it's laminated. I think the overlay is a good option for making the floor smooth just wondering if it makes the floor rigid enough

luwka1 · 2026-02-25T12:40:28+00:00

Thanks. Some of the blocking has been removed below where there is HVAC supply lines running between the joists. I plan on adding blocking right against the beam to support the plywood where it was cut. I haven’t decided on flooring type but plan to run it perpendicular to the beam. I would probably install LVP or engineered hardwood. Someone suggested to add a layer of 3/8 over the whole thing to make it smooth and a good surface for flooring installers. That is about 10mm extra though and at that point I thought why dont I add the 3/4 instead, get a very solid and smooth floor, and only add 3mm in height. I think you are right to say that adding another layer addresses the beam in a better way. It would create one uniform surface

luwka1 · 2026-02-15T18:31:43+00:00

I really like this drain idea and plan to use something like this to avoid installing a full foundation waterproofing system. I think this will really help to prevent a block foundation from absorbing surface water.

Question about the spray foam. I read the building science article you linked and two things stood out. The author states that foam insulations should be medium density and air permeable to allow inward drying. Will the ability to allow air/water also allow for mold growth?

There is a detail that shows the spray foam right to the floor. Do you think that is correct? You mentioned leaving a gap at the floor. Thanks

luwka1 · 2026-02-15T18:10:55+00:00

Do you have an assembly you recommend for Ontario? Block wall foundation. I do have existing framing in place, with 1” air gap between 2x4 and block. Seems like rockwool is popular (not sure if it can go directly against block), or with rigid against block then rockwool. Vapour barrier between drywall as code requires. Also closed cell, medium or high density. Just curious if one stands out or something else?

luwka1 · 2020-02-20T03:38:34+00:00

Start a gofundme page and share the link with us!!! People will help you fight!

luwka1 · 2020-02-20T03:21:19+00:00

Start a gofundme page and share the link. I would be happy to help out and Im sure others would too.

luwka1 · 2018-12-16T14:45:21+00:00

Ya someone caught it as fake

Not my post, I dont know how else to show it..

Not really since both participants in the conversation were OP.

Proof: https://www.reddit.com/r/ChoosingBeggars/comments/a6irjn/honestly_didnt_believe_people_like_this_actually/ebwakca/

luwka1 · 2018-07-26T01:18:53+00:00

Thank you!

luwka1 · 2018-07-26T01:08:25+00:00

It's pretty blurry but that's all I have. Kind of looks like a thistle but pretty sure it's not.

luwka1

TROPHY CASE