Latest Discussions : HVAC


12:42AM | 11/09/08
Member Since: 11/08/08
3 lifetime posts
I want to insulate the ceiling in my garage. When the house was built 10 years ago, the walls attached to the house were done, and the ceiling was drywalled (Fire code). However, they did not put a vapor barrier, before drywalling. I live in Canada. Winter is about six, seven months long. I have access to above the garage. Should I staple a vapor barrier over the joices, and in between, then put my insulation?

I just want to be able to work in there once in a while, over the winter. I already put vapor barrier and insulated the outside walls. Going to heat it with a couple of ceramic heaters. The roof is well ventilated, with soffit vents, and a whirlybird. The roof is made with 2x4 trusses on two foot centres, and they used metal channeling to screw the drywall to.


04:58AM | 11/09/08
Member Since: 04/25/05
1915 lifetime posts
First of all a garage is not a signicant source of vapor as it is not occupied that much and you don't cook or bath in in it.

And the ceiling acts as a enough of a vapor retarder. Specially with good ventalation in the attic space.


05:52AM | 11/11/08
Member Since: 11/08/08
3 lifetime posts
The ground here is frozen until the middle of May, then it starts to warm up. What about when the outside temperature is warmer then the temperature in the garage? Wouldn't there be vapor then. Couldn't you get condensation on the bottom of the insulation, and drywall above the ceiling?

I want to heat it so I can work in there comfortably. I have a motorcycle I want to customize over the winter.


05:59AM | 11/11/08
Member Since: 11/08/08
3 lifetime posts
I was just thinking about what you said Bill. It's making some sense. If the ceiling is retarding the vapor, then if you paint it with a latex paint, that would even be more of a retarder, right?


10:34AM | 03/04/12
Member Since: 03/04/12
1 lifetime posts
I built my home in 2008 and did not intent on heating garage here in Wisconsin in winter , since moving in have used space Heater out there several times throughout winter doing the odd project. I taped and finished drywall and painted to look nice in 2008. The joints have all opened and drywall mud is falling out of ceiling joints. I should have placed vapor barrier since I finished joints. The roof has continuous ridgeventing so air flow is not the culpret. If you don't ever intent on taping and finishing I would agree with not putting plastic up. But for extra 20 bucks I would say just do it in case you decide to tape and paint.


05:43PM | 07/01/13
Vapour barrier is on the top of the rafter then insul then board if heating garage insul vapour then board need hatch for summer to let out hot air I'm a insulator typar is a better product in a garage


08:35AM | 11/27/20
I moved in 17 years ago and and like retro I live up in the snow belt of Ontario Canada. The garage has been completely mudded and painted but I now have added a gas heater to warm it up a bit. The ceilings and walls are not insulated and when the drywall was installed on the ceiling there was no vapor barrier put in place for future insulating. I am wondering whether to cut the poly and staple in between trusses before placing the insulation. I just worry that the gap left under the trusses where drywalled will become a spot of moisture build up

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