Insulating Garage and Crawl space.

[Cudajas]

A 3 for 1 post for me.

I want to insulate my attached garage.

First I need to tackle the wall attached to the house. Yes its insulated, but its 40 years old, so it could be upgraded a bit. That and I need to replace some of the drywall anyway. Is it acceptable to the vapor barrier on garage side of the wall? is it ok to have vapor barrier on both sides of the wall?

For the rest of the garage, the first 3 feet of the wall is concrete. here is a pic.



Is there any way to insulate this part of the walls without sacrificing space?

Last question, I swear. I have a crawlspace under the first floor of my house. It is a fair size space with a concrete floor and there is heat in there. Would it make any sense to insulate this space??? Just seems like it would help keep the main floor a little warmer during the winter.

Thanks for the help guys.

Jason

 

[Cudajas]

btt!

 

[Randy in Maine]

I insulated the concrete block wall of my crawlspace using 2" foil backed foam (from Home Depot) attached to the walls using concrete screws and fender washers with taped joints. It is only about R-13 or so, but really helps to keep it warm under there and greatly decresed any infiltration. Makes it a lot brighter down there also. It keeps the pipes from freezing even here in Maine.

I would think you could do something similar to your garage also and perhaps even better with a few add ons.

Seen this?

http://http://www.youtube.com/watch?feature=player_detailpage&v=i1guAwzyEOQ

 

[chamoisfive]

I've been in construction for a good number of years, mainly domestic, and it is my fervent belief that you cannot (should not) scrimp on insulation. If there is an opportunity to insulate, DO IT! For your own personal peace of mind AND the bottom line, living comfort, DO IT!
The vapour barrier is only needed on the outside (non-living) side of the framing. It is there to prevent any liquid water penetrating to the framing/inside of the house, but allows water vapour to freely exit the wall cavity. I don't see any benefit for you in putting a layer to the inside as well, in fact may be adversely detrimental. The vapour passing thru may well condense to liquid & be trapped inside the wall cavity, - thinking rotted wood, black mould, therefore major potential health issues in future. I would not recommend a dual layer of vapour barrier as you describe. Good luck with your project, hope my comment helps.
Umm, what does btt mean / stand for?

 

[Randy in Maine]

BTT= Bump To Top

 

[chamoisfive]

Thanks for that. Hard to keep up with some of these acronyms.

 

[Randy in Maine]

KYA = Know Your Acronyms.

 

[CNGsaves]

TOO LITTLE INFORMATION.

Is this is coldest part of Canada, or Tampa, FL . . . . makes a BIG difference on the strategy !!

Now would be good time to Update GJ Profile with Location.

As general rule, you want the vapor barrier on the "warm" side of wall, then insulation.

For the 3 ft concrete stubwall, you could skin with 1" foam insulation with 1" strips (say 24" on center), then vapor barrier and lastly attach sheetrock over the top. For walls, use roll insulation then whatever foam is necessary to get upper wall even with lower stubwall, then vapor barrier and finally sheetrock.

HOWEVER, the VERY FIRST thing you need to do is PLAN ELECTRICAL and get all that done PRIOR TO any insulating or sheetrock. Also, install any low voltage like phone/internet/TV/intercom/security/etc BEFORE the walls are closed up.

Along with planning electrical, also plan any heating/cooling so you'll know where all will be going. Any airline system also needs planned.

So moral of story is PLAN, Plan, & PLAN !! Good luck.

 

[Cudajas]

TOO LITTLE INFORMATION.

Is this is coldest part of Canada, or Tampa, FL . . . . makes a BIG difference on the strategy !!

Now would be good time to Update GJ Profile with Location.

As general rule, you want the vapor barrier on the "warm" side of wall, then insulation.

Good point. I am in Southern Ontario, Canada, so cold yes...but not the coldest part.

That's what I thought on the vapor barrier. I assume that there is vapor barrier on the warm (house) side of the wall. I am going to go in from the garage side. so I will not add any vapor barrier on that side.

The stem wall, I think I will leave for now. I think doing anything will eat up too much space.

I hear you on the electrical...just not sure its in the budget now. The whole garage is on one circuit...3 outlets and two lights. I think it would be better to run a dedicated panel to the garage and wire from there...but not sure how much that will run me!

I insulated the concrete block wall of my crawlspace using 2" foil backed foam (from Home Depot) attached to the walls using concrete screws and fender washers with taped joints. It is only about R-13 or so, but really helps to keep it warm under there and greatly decresed any infiltration. Makes it a lot brighter down there also. It keeps the pipes from freezing even here in Maine.

I would think you could do something similar to your garage also and perhaps even better with a few add ons.

Seen this?

http://http://www.youtube.com/watch?...&v=i1guAwzyEOQ

I will look into do that. The link does not work BTW.

Thanks for all the help guys.

Jason

 

[jvitez]

+1 on no extra vapour barrier on the garage side of the shared house/garage wall. You never want a double vapour barrier because any moisture that does occur will be trapped and cause rot.

For the concrete wall you have a few choices:

1. Rigid foam insulation glued to the concrete with drywall over top. You'd need to use concrete fasteners to attach the drywall. Plasti-fab sells 3" Plasti-span expanded polystyrene foam sheets at R12.

2. Frame out a stud wall and insulate the stud spaces as you would any framed wall. Use Roxul, it's waterproof and higher R-value. Negative is losing some width to your garage space.

3. Combine both. Put 1" of styrofoam on the wall and build a stud wall over top. No conductive heat loss through the studs with this method.

4. Build a 2x4 stud wall 3.5 inches away from the concrete wall. Run R-12 batt insulation horizontally behind the stud wall and R-12 vertically in the stud spaces. R24 wall, nice and toasty. Cons: you'll lose 14" of garage width. Pros: higher R-value, and no conductive heat loss through the studs.