Ceiling Vapor Barrier in Heater Garage

[puppycrack]

I live in Rochester, NY with a 3 1/2-car attached garage. 10' ceilings in 2 bays, and 12' ceiling in the 3rd bay. The house was built in 2008. The builder rocked the walls and ceilings, and looks like they all got one coat of paint. I'm not sure what's in the walls, but the ceiling was originally uninsulated. Part of the garage attic (maybe 10-15%) is above the heated portion of the house. The attic is unfinished, and is used to store light bulky items (like kids toys). Water containment mats are in place for the two cars in the garage, and I'm pretty good about removing pools of water w/ a wet vac as snow melts from the cars.

I added R-38 unfaced insulation in the attic above the garage ceiling a couple of years ago, as I was doing light work on the weekends, and was running a heater. Soffit baffles were added where needed. I also added a pull-down ladder to the attic, and added the fiberglass "tent" on top to try to seal better, which worked well.

I currently heat the garage on some weekends (electric heat), but am considering running a 1300 watt oil filled heater pretty much 24/7 in the very cold winter months. This would keep the Garage temps at the 45-50 range pretty consistently.

I've read numerous threads regarding installing a vapor barrier in a heated Garage. From everything I've read, it is definitely recommended, but am wondering how critical it really is. Do I have a recipe for disaster here? Should I be thinking about taking down the drywall ceiling to install a proper vapor barrier? Or should I remove the insulation and replace with Kraft faced insulation? The attic seems to have good airflow from soffit and ridge vents, but I don't want to create a mold nightmare up there. Over the past 7 days, humidity levels in the garage have hovered around 40%, save for one day of constant rain where they jumped to 55%.

Thoughts, insights, and comments are most appreciated.

Thanks,
-pc

 

[dmdc411]

I'm in Minnesota. My 3 stall attached garage has insulated walls and ceiling. No vapor barriers. Only because, initially there was no insulation in the exterior walls. I pulled down the lower sheets to add wiring for outlets. House was built in 2000 with one outlet in the garage. How stupid is all I can think! I insulted the walls a best I could with rolled glass. Taped & mudded all excepted the perimeter of the ceiling. My thoughts, leave an escape path for moisture. I park all year round. I heat with a vented gas ceiling mounted heater. (Hotdog by Modine). It works great! No issues with moisture, or mold. Only issue, all my tape joints cracked. I know that's because I don't continuously heat. It's a garage, but I keep warm. All that matters!

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[Jazz1]

For what little cost/work to install vapour barrier do it once, do it right. POOR MAN PAY TWICE!
I built my garage insulated/vapour barrier and drywalled.
I heat with woodstove although not 24/7 and humidity does not go above 50 ever.

 

[puppycrack]

For what little cost/work to install vapour barrier do it once, do it right. POOR MAN PAY TWICE!
I built my garage insulated/vapour barrier and drywalled.
I heat with woodstove although not 24/7 and humidity does not go above 50 ever.

If it weren't for the fact that the ceiling is already rocked, and have installed $700 worth of insulation up there, I would absolutely be spending the $$$ for some 6-mil sheeting. Removing 800+ sq. ft. of drywall ceiling and replacing, or spending upwards of $1000 for new insulation, is no small cost or amount of work.

 

[katmat]

If you are worried about it, why don't you put a vapor barrier on the existing drywall & then install new drywall or find a drywall w/ a vapor backing.

 

[puppycrack]

If you are worried about it, why don't you put a vapor barrier on the existing drywall & then install new drywall or find a drywall w/ a vapor backing.

Unfortunately, I don't know *if* I should be worried about it, given the situation. I was hoping someone could chime in and give me an informed opinion on how bad it really is, or whether I'm making a mountain out of a mole hill...

 

[f150skidoo]

My garage was drywall originally with no insulation and last year I decided to insulate the garage and use it as my shop. I pulled down all the drywall on the walls to insulate and vapor barrier, but decided to leave the original non vapor barrier ceiling as is. Mostly because I did'nt want to take down and reinstall 5/8" fire rated drywall on my 14' tall ceiling. I was also concerned about not having vapor barrier but I found a INSL-X primer sealer that had a permeability rating of 0.8 which is similar rating to the kraft facing insulation or polystyrene rigid foam. I consulted my uncle who is a retired building inspector and he felt that good paint with a perm rating on the ceiling and proper venting in the attic would be no issues with mold or sweating on the drywall. My shop is heated 24/7 with R40 in the attic and theirs be no issues.

 

[kbs2244]

First, I am surprised there is no attic fire wall in the attic between that over the living space and the garage.
I thought that was a nation wide fire code.

But to your question:
Make sure your new heater is a vented one.
That will take care of any added vapor problems.

Then apply two thick coats of an oil base paint the ceiling.
It wouldn't hurt to do the wall while you are at it.

It is not the perfect answer, but it will work if you keep the floor dry.

 

[puppycrack]

I just went up into the attic to see if I could find evidence of any mildew or mold. I guess I completely forgot that I did indeed install Kraft backed fiberglass insulation. Being as this is the case, would I still be in a better place with vapor barrier paint, or am I good? Sorry for in accurate OP.

 

[ItsNemo]

There are paints you can use as a vapor barrier...a lot easier/cheaper than trying to redo the drywall.

 

[dfiler2]

This^^^

https://www.zoro.com/zinsser-mold-and-mildew-paint-1-gal-white-270267/i/G6091836/#specifications

 

[Jazz1]

Ok,, i would send the kids up there to remove all the insulation, then have them lay down vapour barrier and put the recovered insulation back in place. Cost would only be the vapour barrier.

 

[ItsNemo]

Ok,, i would send the kids up there to remove all the insulation, then have them lay down vapour barrier and put the recovered insulation back in place. Cost would only be the vapour barrier.

Not ideal, that will leave air spaces between the insulation/vapor barrier/drywall.

 

[kbs2244]

Paint it, provide ventilation, and move on.