Advice request for best insulation for unique window situation

Submitted by Clear_Lingonberry22 t3_zk5wl1 in DIY

I live in New England.

I’ve got a basement window frame that my sump pump drain runs through. The inside of the frame is plywood, then there’s the sill gap, followed by mesh on the outside of the frame. A hole has been cut through the plywood and mesh to accommodate the 1-1/2” drain pipe.

Previous owner basically used a vacuum tube for the drain pipe, 1/4” plywood, and expanding foam as caulking. So am going to be replacing the pipe with PVC, as well as the plywood with 3/4” (coated for water resistance), and silicone caulk.

I’m looking to put insulation in the space between the plywood and the mesh screen. Should I be using styrofoam, fiberglass batts, or something else?

Thank you.

Edit: picture of exterior included

https://imgur.com/a/eKIHWKA

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Comments

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Kesshh t1_izxy6jq wrote

Wouldn’t that expose to insulation to the elements? Might help if we can see a picture?

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Clear_Lingonberry22 OP t1_izy0hln wrote

Thank you. Just edited to include an exterior picture. Yes, it’ll be exposed to wind and temperature. The window/foundation sits about 6 inches recessed from the siding of the house, which keeps most rain off of it, and it would take a good foot of snow to reach it.

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Kesshh t1_izy1dyc wrote

So the screen really doesn’t serve any purpose, right? It doesn’t stop bug, it doesn’t ventilate (or does it? Think I see the whole opening is covered by plywood.).

In that case, would you not consider building a mini-wall? From the outside in, some sort of exterior covering/siding/etc., vapor barrier, plywood, insulation, plywood, interior wall.

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Clear_Lingonberry22 OP t1_izy629x wrote

Yeah, the mesh doesn’t really have a purpose. I like that wall idea, thank you.

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humanefly t1_izz1mv6 wrote

I'd just use styrofoam and seal with spray foam. Maybe consider wrapping the new PVC pipe with a bit of pipe insulation on the inside for a foot or two, for the reason that if cold air comes into the pipe and starts going inside, you are probably likely to see condensation forming on the pipe, where it goes through the screen and inside where the pipe is colder than the air.

I'd also consider some kind of one way valve or flap on the outside of the pipe to keep cold air from flowing into the basement. You'll have to be a little careful to check that the flap is never impeded and it's always working and free to open

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anent_life t1_j02ia7a wrote

In the past I removed the screen and replaced it with a piece of plywood where i glued the thickest pink rigid foam insulation that would fit in the gap. After it was in place, I sealed it with spray foam from the inside. If nobody was going to see it I would do it again from the outside. But I am minimally handy.

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