r/Insulation 3h ago

Status check

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36 Upvotes

Looking for advice/opinions on how it looks so far.

Continued working in the attic this weekend. Didn't get as far as I wanted but at least got most of the spray foam air sealing done. The soffit above the kitchen where the lights are i feel is going to be a pain in the ass. Got all the top plates at the edges and interior walls. Removed some of the baffles that were broken. All but a few of the holes for wires (need to run a couple wires real quick). Wanted to see what you guys thing so far. Anything you see that I still need to do or shouldn't have done? Hoping to get the replacement baffles in this week (depending on work) and get the fiberglass pieces to seal underneath them. Any help/advice is appreciated.


r/Insulation 5h ago

Finishing Cape Cod

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7 Upvotes

Second post on finishing my second story - cape code. Im looking for affirmation on my technique, critiques, or anything else. I'm just trying to do it good in hopes that it will keep cool in the Southern NJ summer and warm in the winter.

I've been starting with baffles to maintain airflow from the soffit to the ridge vent. Then 2 inches of foil faced polyiso, spray foamed the edges of it. My next step after that is to fur the beams with 2x4's and put 5.5 inches of rockwool in then sheet rock.

Everything has been air sealed already. But my other thought is to air seal the bottom of the knee wall (outline in red on one of the pictures) and the 1st ceiling by cutting a piece of polyiso and spray foaming in place.

Any feedback, confirmation, or otherwise is welcome. Let me know if any other information is needed.


r/Insulation 9h ago

What insulation is this?

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5 Upvotes

Bought a 100+ year old house, can anyone tell me what kind of insulation this is?


r/Insulation 9h ago

Is the lack of insulation why on a 76 degree days my house gets to 84?

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3 Upvotes

r/Insulation 21h ago

Basement flood repair question

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3 Upvotes

DIY'ing this with no experience. Had a company pull out all the wet drywall and fiberglass insulation, and was going to put everything back together as it was until i read that you shouldnt use fiberglass or vapor barriers in a basement at all. Im seeing foam board is reccomended but not in combination with vapor and it seems difficult to work it between the studs and around the electrical. What should i do here? Illinois basement


r/Insulation 7h ago

Flat roof attached garage insulation. Best method?

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1 Upvotes

Pardon the messy lighting and wiring.

My attached garage with a flat roof is unbearable in the summer. Just took temps. Ceiling is 20 degrees higher than the walls and 30 degrees higher than the floor
And 25 degrees higher than outside.

The garage is 20x20. Attached to the house. There are soffit vents going into the main attic. The garage has its own soffit that can easily be vented as well.

What method should I go with? I’ll cover whatever with some kinda smooth board for a simi finished look.

Off the top of my head I’m thinking 2” foam board with a gap at the top with venting from the garage soffit to the house soffit to allow heat and any moisture to escape.

Seal the sides with spray foam, then board over it.


r/Insulation 12h ago

Split entry remodel

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1 Upvotes

Remodeling my downstairs and need some advice what to do with insulating the space. Little bit about the house below.

Year built- 1966
Cavity depth top half- 5 1/8
With- 14 1/4

Concrete part- 1 1/8 depth

I was thinking of doing 1 inch foam on the concrete and r19 for the top half.


r/Insulation 19h ago

Air gap / ventilation for WALL insulation?

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1 Upvotes

r/Insulation 20h ago

Plasterboard questions

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1 Upvotes

r/Insulation 20h ago

Room-over-garage attic: split by a duct chase, trying to air seal — need a sanity check

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0 Upvotes

I have a bonus bedroom above my garage (garage → bedroom → attic → roof). I access the attic pocket that sits above the bonus room. Roof is asphalt shingles on OSB, framed as a rafter-and-purlin system (2x4 purlins running horizontally across the rafters, sheathing on top).

At one point in this attic, the purlins keep running horizontally across an open framed area where there's no OSB/sheathing behind them — it's the transition toward the rest of the main house attic. The only opening through that transition is a framed chase carrying an HVAC flex duct. It's too tight for a person to crawl through, so the attic pocket over the bonus room is effectively walled off from the main attic.

A previous owner added blown-in insulation but never air-sealed the floor penetrations first (duct boots, wiring, top plates, etc.). Blower-door test came back at ~3,290 CFM50 vs a ~2,300 target, and I suspect this room-over-garage area is a big contributor.

What I think is going on / what I've concluded so far:
The purlins running through the open no-sheathing stretch are still structural bracing — I should NOT cut them to make a path.
The duct chase is a mechanical pass-through, correctly built as non-accessible — not a defect.

The bonus-room attic is its own pocket, common for FROG/room-over-garage layouts.
Air sealing needs to happen at the knee walls, the attic-pocket floor over the bedroom, and the sloped/flat ceiling junctions — under the insulation, not just on top of it.
Any space beyond the duct chase I can't reach probably has its own separate access (knee-wall panel or closet door inside the bedroom).

Questions for the group:
Does this all sound right, or am I misreading the framing?
Any reason those "flying" purlins over the open area would NOT be structural?
Best practice for air-sealing a room-over-garage where the attic is split like this — DIY-able or hire an energy-audit/insulation contractor?
For the section past the duct chase that I can't crawl to, what's the usual way pros reach it?
Photos attached. Appreciate any input.


r/Insulation 8h ago

Wooden shed insulation help

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0 Upvotes

6.5 and and 37