Insulation question

[WormWiggler]

I contacted a company for an estimate to have insulation installed in the attic space above my garage. The contact person mentioned installing the insulation up tight in the rafter spans instead of the below your feet joists. I thought this was odd and worry about condensation, any thoughts?

 

[Trip McNeely]

Im not a roof guy but i would think this may not be a good idea. I would think this would not allow the attic to vent properly and could potentially harm your shingles..... also if you heat your garage why pay to heat your attic because the heat will inevitably rise up to the rafters. Not an expert but I would keep it in the joists just above the sheetrock.....

 

[Petras]

I would say it depends how your house is built. Do you have attic vents? If so, then you'd want to insulate right on top of the sheet rock. If your house has no attic vents(ridge vents or Gable vents and soffit vents) to move air in the attic, and you intend to insulate the end walls as well, I suppose you could insulate the roof instead. Just be DAMNED sure it is very well insulated and sealed up. Hot and cold air mixing in the winter creates condensation that freezes. Spring rolls around and thaws that condensation out and next thing ya know you have water running down the inside of your walls in the house creating mold issues ..

 

[WormWiggler]

It was built in the 80s, pretty sure there is ridgeline and soffit vents.

 

[Obi-Wan]

What type of insulation ?

 

[WormWiggler]

I think it is the closed cell foam

 

[Retired Educator]

I think everybody's correct above. Condensation could be a problem. Condensation is created when cold air and warm air meet. If the closed cell foam is properly installed and sealed in the rafters there will be no cold air coming in. I'm guessing the closed cell would work better in the rafters as there is more to attached to and allows for an even layer of insulation.

On the other hand, how do you get any air circulation in the attic. Without the air moving it could get pretty stale. One of the reasons for insulation above the sheetrock is to not heat that area in the winter and also to keep air moving in the summer to help keep the house cooler. Regardless of what you do keep in mind the air circulation.

 

[raider]

https://www.youtube.com/watch?v=7SpEjIuSQn8

 

[3Roosters]

I'd get another estimate from another company and see what they would recommend.

 

[LBrandt]

Unless you want your attic warm insulate the floor joists or moisture could become a problem.

 

[johnr]

I’d just move

 

[Bfishn]

Yeah i think for garage you want the insulation on the Sheetrock, for actual house attic I could understand doing it the other way i suppose. Pretty cheap and easy to buy the insulation and use the machine from Menards an blow it in yourself, so easy even i could do it.

 

[BrokenBackJack]

https://www.youtube.com/watch?v=7SpEjIuSQn8

This is how they did our new house in AZ last year. We have our air exchangers in the attics. 1 in house for house and 1 in garage for garage. I questioned it and even went to the city engineer and he said that is how they do it now here when you have the exchangers in the attic. Have 2 heat pumps outside, 1 for garage and 1 for house. Cools in the summer and heats in the winter.
The vents are totally sealed up. Still doesn't make sense to me as we were taught the attic has to breathe. Will see how it goes. Sure different than the way this farm boy was taught growing up in NoDak.

 

[shorthairsrus]

my question

-- and i have not been able to check this out as the wife just bought one and i cant get in. The typical three stall that is attached to the house ----- the i see the ceiling of the garage is rocked. I asked if it had insulation and they said no --- I dont see vents -- how do i vent that garage --- i am sure it has soffit ventilation --- not sure what else. How are most of them vented.

 

[Maddog]

my question

-- and i have not been able to check this out as the wife just bought one and i cant get in. The typical three stall that is attached to the house ----- the i see the ceiling of the garage is rocked. I asked if it had insulation and they said no --- I dont see vents -- how do i vent that garage --- i am sure it has soffit ventilation --- not sure what else. How are most of them vented.

I believe most now a days most new construction has soffit vents and then ridge vents at the peak of your roof line. (the "pot" vents don't do a good job as they leave dead spots with no air flow up at the peak of your roof. ) I understood the goal isn't so much to cool the attic, but to get a little air flow so you don't get condensation.

 

[JayKay]

Soffit vents bring air in, through the soffit. It comes up between the trusses. If you are going to insulate the attic floor (above the sheetrock), then you need to make sure that you put in the 'chutes' that allow the soffit vents to work. The air in the attic should be as cold as the air outside. You can tell a poorly insulated house in the winter, becuase the snow melts off the roof right away. Or, you can see the truss marks in the frost.

Ridge vent is probably the best (aside from the soffit vents), but ridgevent can only be put in while a new roof is going on. Or rather, it'd be a pain.

Otherwise, enough regular roof vents help. Of course, a powered attic fan moves a lot of air too. that'd be better.

 

[shorthairsrus]

I relooked it has vents on the main home -- but the connected garage nothing --- can i cut vents into the shingles without messing them up?

Dammit i just put some in my currrent stand alone garage so i could heat it and now the wife throws a wrench in it.

 

[CWS]

This topic has been on my mind recently, im glad it was brought up. we moved into a house last fall and it seemed difficult to heat and there was quite a bit of moisture on the sliding door and we noticed some in the corner of the exterior wall of our bedroom. This summer it was hard to keep the house cool, got new AC unit because it was about 30years old. I went up into the attic to look around and there are some of those baffles in the joists but there not properly inserted. I know I need to get up there and put new ones in and fix the current ones. Would that help with keeping my house cool in the summer and warmer in the winter? I do feel there isn't sufficient air flow in the attic, there are soffit vents but how much of a difference does the baffles or chutes make?

 

[johnr]

I’d divorce her

 

[BrokenBackJack]

This topic has been on my mind recently, im glad it was brought up. we moved into a house last fall and it seemed difficult to heat and there was quite a bit of moisture on the sliding door and we noticed some in the corner of the exterior wall of our bedroom. This summer it was hard to keep the house cool, got new AC unit because it was about 30years old. I went up into the attic to look around and there are some of those baffles in the joists but there not properly inserted. I know I need to get up there and put new ones in and fix the current ones. Would that help with keeping my house cool in the summer and warmer in the winter? I do feel there isn't sufficient air flow in the attic, there are soffit vents but how much of a difference does the baffles or chutes make?

Your baffles or chutes allow air to come through the soffits and up into the attic then the air rises and should go out the roof vents.
You might not have enough insulation in the attic if it is hard to heat and cool also.