Insulation, vapour barrier and roof vents in detach garage

[88CRX]

Planning on insulating, vb and drywalling a detached garage, which will remain unheated for now. There are a couple roof vents (square box style) but that's it. Can't do soffit venting because of garage property line setbacks. I could maybe add some gable vents but dont see that really helping.

Should I even bother with ceiling vb? Should I bother with any vb? Attic is going to be an oven in the summer.

Whats everyone done in their detached garages?

[masoncgy]

Your garage has absolutely no overhang on any sides?

[Rarasaurus]

I had the same issue and added Gable vents. Better more venting than not enough. The top square vents arent enough to circulate the air. You can also look at the fan type top vents.

Without vapour barrier the moisture will move into your insulation and create mold. VB in our climate is a good idea. Specially if you ever want to heat the garage.

[benyl]

Hope you have a drain or plan on active venting (fan).

Cause it is going to be hella humid in there with the VB.

[bspot]

My garage has no soffit venting and is insulated and vinyl sided on the inside (I didn't do it... don't ask).

I'm having insane humidity issues, so I've got a through-the-wall fan and a dehumidistat/temperature controller on their way. The fan will kick in when the humidity is too high or the garage is too hot and exchange the air.

I know it will keep the garage colder over winter, but I'm tired of my tools and hockey equipment rusting and worried it will start to affect the cars.

The attic gets crazy hot, but I'm assuming the only negative there is shortened roof life span?

[Darell_n]

Originally posted by benyl
Hope you have a drain or plan on active venting (fan).

Cause it is going to be hella humid in there with the VB.

No.

[88CRX]

There is a small overhang on the sides but building code dictates no vented soffit within a certain distance of the property line.

Maybe I'll just throw up a couple gable vents come spring.

As for moisture inside the garage, how much snow and ice are you guys bringing in? I've never had that problem in attached garages.

[A2VR6]

Originally posted by 88CRX

As for moisture inside the garage, how much snow and ice are you guys bringing in? I've never had that problem in attached garages.


Not very much at all in my detached garage... atleast none that I noticed.

[firebane]

Whirly fans on the roof if you can will move a lot of air through that attic area. If not then just put gable vents but make sure you screen them well.

[masoncgy]

Originally posted by bspot
The attic gets crazy hot, but I'm assuming the only negative there is shortened roof life span?

If it is humid enough up there, you have a perfect breeding ground for mold. When's the last time you popped your head up there with a flashlight and looked around?

To the OP... I wouldn't completely seal up your garage interior if you are not going to have sufficient ventilation available to keep the air dry and moving in the attic space. You'll end up with humidity & moisture problems in there, guaranteed.

[bspot]

Originally posted by masoncgy


If it is humid enough up there, you have a perfect breeding ground for mold. When's the last time you popped your head up there with a flashlight and looked around?

I'm up there a couple times a year. It's only hot in summer when the thing is bone dry, so I think I'm good. I have several ridge vents.