Garage ceiling insulation

[Junk]

Getting insulated doors installed next week. My garage has a finished ceiling of s***rock under the joists. Joists are 2x6, 16 on center. What's the best insulation and do I go with a vapor barrier or not - regular bats, blow in, R-what? No sense in doing the heater till it's insulated.

 

[Icantdive55]

Getting insulated doors installed next week. My garage has a finished ceiling of ****rock under the joists. Joists are 2x6, 16 on center. What's the best insulation and do I go with a vapor barrier or not - regular bats, blow in, R-what? No sense in doing the heater till it's insulated.

R21 batts. no real need for the vapor barrier. Blow in insulation is great unless you want to access the attic for storage or something. Batts can always be moved arround for doing repairs etc.

 

[Capt. Jim]

R21 batts. no real need for the vapor barrier.

I disagree. A vapor barrier will help prevent condensation occurring in your insulation as a result of the moisture gradient that occurs in colder winter months. This causes moisture to migrate from the warmer interior of the garage to the colder area of the attic.

Mosture accumulation in your insulation will cause the insulating value of the insulation to decrease. Other problems with lack of a properly installed moisture barrier, which we now call a moisture retarder, can be staining on the drywall as well as fungal growth on drywall backing and wood framing members. Installing an effective moisture retarder is harder once the sheetrock has been installed.

 

[NMuzj100]

Will this be heated full-time ? Houses are built w/ R-49 in the attic but that is with 65 degrees 24/7 as the planning consideration.

I understand NJ can be pretty cold. If you plan to heat it with electric or propane then the insulation will pay for itself pretty quick.

If you still want a vapor barrier then reverse-faced batts could be used between the joists first.

 

[valentine]

I have 2x4 trusses.

I put bat insulation with the vapor barrier down (against top of s***rock) then covered it all with plywood so I can still use the attic to put all my wife's worthless s*** up there.

Works great for me......

Now fxxxalong

 

[Junk]

I have 2x4 trusses.

I put bat insulation with the vapor barrier down (against top of s***rock) then covered it all with plywood so I can still use the attic to put all my wife's worthless s*** up there.

Works great for me......

Now fxxxalong

Yeah, that's what I plan on doing except my piece of crap joists are 2x6, so yet again mine is bigger .

I wasn't sure though about the vapor barrier because the home china store has 1/2 their crack staff saying no barrier and the other 1/2 saying yes.

 

[Junk]

Will this be heated full-time ? Houses are built w/ R-49 in the attic but that is with 65 degrees 24/7 as the planning consideration.

I understand NJ can be pretty cold. If you plan to heat it with electric or propane then the insulation will pay for itself pretty quick.

If you still want a vapor barrier then reverse-faced batts could be used between the joists first.

Usually unheated, but will have a heater out there (probably just a small one for now and eventually a modine) to take the chill off for when I'm out there.

 

[1.25Ton]

Blow in R-30 and be done.

 

[photogod]

Last I looked, blow in was basically shredded news print. Been a while since I looked. I would go with no VB since you already have the sheet rock there and go with bare fiberglass insulation as it will pass the moisture where blown in tends to trap moisture. Second choice would be the reverse VB glass. Be sure to vent your roof as it will trap moisture and pop the plywood.

 

[NMuzj100]

My blow-in insulation is little pink fiberglass balls the size of mini-marshmellows. I would avoid the newspaper type. Outside of the vapor issues I worry about how chemically loaded it has to be to meet fire standards.

Anyone used the new "encapsulated" bats that are supposedly "itchless".

 

[90FJ62]

I have a stand alone shop and plan on using this on the walls and ceiling.
http://www.insulation4less.com/highr_FfmF.asp

May not be R49 but will work for what I need.

Dave

 

[rusty_tlc]

Usually unheated, but will have a heater out there (probably just a small one for now and eventually a modine) to take the chill off for when I'm out there.

If you use one of the LPG units they generate a huge amount of water vapor. From what I remember of NJ it isn't the driest place around, so a vapor barrier might be a good idea.

FWIW I use a little Reddy heater. It takes the chill off in under fifteen minutes in my three car garage.
Around here the humidity isn't an issue.

 

["N8"]

as a carpenter we always install a vaper barrier torwards the living space so in your case down torward the sheetrock. this is for reasons alredy mentioned. you dont have to staple it inside a joist bay just chuck it in there! remember to keep the insulation as fluffy as possible for eficency, and when you get it all over yourself cold watter in the shower as hot watter will open up your pores and suck the crap further into your skin. have fun!

 

[Scamper]

Since you're installing it in the basement/garage, the vapor barrier should go up against the flooring. That way, the warm/moist air coming from the house won't condense in the insulation and fauk it all up.

If you have any pipes in those joists, now would also be a good time to relocate them if necessary up against the floor so that when you insulate, they'll be kept in the warm (since you don't plan to heat the garage).

You're also going to need to re-rock the ceiling and tape it--it be fire code here in Jersey.

 

[Junk]

You're also going to need to re-rock the ceiling and tape it--it be fire code here in Jersey.

Hey Scamper. Have to re-rock the ceiling? You sure about that? I'm not changing the garage at all, simply tossing down a layer of insulation in the attic above the garage. What would be the reason why they would want it re-rocked?

 

[Scamper]

Maybe I've misunderstood what you're doing; my reading comprehension is failing as I get older.

I thought you were insulating the ceiling in your basement garage, and inferred that since you're insulating it, you must have living space above it.

If that's the case, it has to be rocked in NJ. They figure that your nasty car will spill gas all over the place and you'll toss your lit cig out the window as you get out of the car and burn your house down while you're asleep. So they want you to have sheetrock in the ceiling so that you'll have a few extra seconds to get out of the car and get to a Wawa (using your second car of course) to buy some Oscar-Mayers to roast over the coals.

Of course, if you're not having the work inspected (i.e., no permit), then the only time it will be a problem is if your house burns down (see above) or when you go to sell it and they make you re-rock it.

Then again, maybe the code is different in Buggerville.

 

[45Kevin]

Vapour barrier goes on the heated side of the insulation. You can buy special paint that forms a vapour barrier. It is very important that you have one. Price the blown in fiberglass and you may find that is about the same price as the batts but it does a better job. Make sure that your soffit vents don't get covered up by insulation.

 

[Junk]

Thanks everyone.

Scamper - the garage is an attached 2 car garage that's on the end of the house (center hall colonial) but has no living space above it - just an attic. The one wall of the garage is shared with the house. Don't know if that helps or not.

 

[Scamper]

the garage is an attached 2 car garage that's on the end of the house (center hall colonial) but has no living space above it - just an attic. The one wall of the garage is shared with the house. Don't know if that helps or not.

Not sure myself in that situation, though I suspect strongly that the local inspector would require it be covered simply because it's attached and still presents a potential "threat" to the house occupant.