Home Improvement

Dandai

Dandai

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I just sealed my crawlspace with spray foam (closed cell). The problem with using it in an attic is that you need to be absolutely certain that your roof is properly water sealed under the shingles. Once you've sealed everything with spray foam you'll never know if it's leaking and rotting the wood under the shingles.
 
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Erronius

Erronius

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Lanx said:
ok, does anyone do this?
Attic Air Sealing Guide - Building America Top Innovation | Department of Energy

at first i'm seeing videos on you about attic sealing, i think it's just bs and just attic guys making commercials, now i see a legit doc from the energy gov ppl...

do i really have to buy like cans of great stuff, argh.

oh, i was thinking about this, cuz when i left for vacation, i went to turn off my main water line in my basement and when i went to reach for it, i was hit by cold ass air. i kinda went to look and where it comes out from the basement, theres no insulation or foam and cold air is just traveling up the wall. came back from vac, threw some insulation in there and sealed it up greatstuff window/door huge crack. then i saw all these attic sealing vids...
Click to expand...

It's legit, but you can hit the point where your return on the cost/effort tapers off, pretty quickly.

My school does an energy efficiency course, and towards the end they do an 'energy audit' on someones house. Thermal camera, blower door, the whole nine 9 yards. You'll see stud/joist pockets with literally no insulation in them, you'll be able to feel where all of the major leaks are, etc. I'm not sure I'd PAY for someone to do one, but /shrug.
 
iannis

iannis

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I think the argument against making your attic airtight is humidity? I don't remember exactly.

My attic is insulated on the floor (ceiling of the 2nd floor rooms) and there are no central air vents up there. There are vents to the outside. If I sealed those off without doing anything else, I'd probably create a problem somehow. It would be a sealed room with totally stagnant air. Hot air in the summer and moist air when it rains. Not sure if that would create a problem or not. But it doesn't sound like a great thing.

It also doesn't sound like a difficult problem to solve. I'd just vent it to the rest of the house.
 
Erronius

Erronius

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iannis said:
I think the argument against making your attic airtight is humidity? I don't remember exactly.

My attic is insulated on the floor (ceiling of the 2nd floor rooms) and there are no central air vents up there. There are vents to the outside. If I sealed those off without doing anything else, I'd probably create a problem somehow. It would be a sealed room with totally stagnant air. Hot air in the summer and moist air when it rains. Not sure if that would create a problem or not. But it doesn't sound like a great thing.

It also doesn't sound like a difficult problem to solve. I'd just vent it to the rest of the house.
Click to expand...

Yeah, it depends on where your boundary is between livable space, and what is essentially the outside. If the barrier is above your ceiling, then everything above that needs to be ventilated I believe. But if your moisture barrier is the roof itself, then that's different.

This has a good explanation (though some of it s over my head; I'm not a generic building guy, or HVAC):

BSD-102: Understanding Attic Ventilation
 
Dandai

Dandai

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iannis said:
I think the argument against making your attic airtight is humidity? I don't remember exactly.

My attic is insulated on the floor (ceiling of the 2nd floor rooms) and there are no central air vents up there. There are vents to the outside. If I sealed those off without doing anything else, I'd probably create a problem somehow. It would be a sealed room with totally stagnant air. Hot air in the summer and moist air when it rains. Not sure if that would create a problem or not. But it doesn't sound like a great thing.

It also doesn't sound like a difficult problem to solve. I'd just vent it to the rest of the house.
Click to expand...
Yeah, you definitely do not want to seal your attic unless you're conditioning that air. For my crawlspace I have a 6" supply and a 6" return so it's balanced. It's rarely going to be the same temperature as the living space, but it's going to be comfortable and not as humid as the outside air.
 
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P

Picasso3

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Lanx said:
ok, does anyone do this?
Attic Air Sealing Guide - Building America Top Innovation | Department of Energy

at first i'm seeing videos on you about attic sealing, i think it's just bs and just attic guys making commercials, now i see a legit doc from the energy gov ppl...

do i really have to buy like cans of great stuff, argh.

oh, i was thinking about this, cuz when i left for vacation, i went to turn off my main water line in my basement and when i went to reach for it, i was hit by cold ass air. i kinda went to look and where it comes out from the basement, theres no insulation or foam and cold air is just traveling up the wall. came back from vac, threw some insulation in there and sealed it up greatstuff window/door huge crack. then i saw all these attic sealing vids...
Click to expand...

Air sealing is big, it doesn't matter how great your insulation is if you're exchanging air. Pipe and wire penetrations can go basement straight to attic and create a chimney effect that cools or heats the inside of your walls, but even worse than that is having direct penetrations like recessed lights, even if covered with fiberglass insulation will still move a lot of air.

It's important to think about it like you're not just stopping stagnant air, with the temperature differentials and potential pressure differentials there's a real flow potential. I've been able to feel drafts through outlets before.

Pop a can of great stuff and just start hitting every hole and penetration you can -- as everyone mentioned you need to clearly identify the borders of conditioned space and that's where you do it all. No bigger facepalm than watching some dipshit insulate the floor above a conditioned basement.
 
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Lanx

Lanx

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Damn you guys
IMG_20190107_203353.jpg


i also got some plywood i'll cut so that i can stand on something flat, instead of standing on the (trushes? is that what the ceiling studs are called?) after doing the pot lights and wiring up the rooms, tired of kneeling 16in apart.
 
Dandai

Dandai

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Lanx said:
at first i made fun of her cuz they jingle a bit, then i was like "oh i can walk ahead and not worry where she's at".
Click to expand...
Do you know the most sensitive part of man’s body during masturbation?

His ears.
 
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BrutulTM

BrutulTM

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Dandai said:
Do you know the most sensitive part of man’s body during masturbation?

His ears.
Click to expand...

I heard a guy say today "Me and the wife have been married so long now that we've gotten into S&M. She sleeps and I masturbate.
 
BrutulTM

BrutulTM

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I'm not sure if Picasso is fucking with you or just too drunk to type but the word you're looking for is "trusses".

trusses.jpg
 
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lurkingdirk

lurkingdirk

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Lanx said:
Damn you guys
View attachment 188944

i also got some plywood i'll cut so that i can stand on something flat, instead of standing on the (trushes? is that what the ceiling studs are called?) after doing the pot lights and wiring up the rooms, tired of kneeling 16in apart.
Click to expand...

You should definitely fill one boot with spray foam. What bad could possibly come of that?
 
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