Garage wall insulation

[64 Thunderbolt]

I recently moved to Concord, NC and bought a house wth an attached 2 car garage.The house and garage are brick and the outer walls of the garage are not insulated. They are covered in plywood with 2x4 framing behind them. My garage is facing the HOT late day evening sun and gets unbareably hot and I'll be honest I don't even want to go out in it. Plans are to insulate the attack and change the garage door to one that is insulated. I also want to add a window A/C unit along with a heater
I only have about a 1/2" of space behind the outer plywood walls to add any insulation.
My question is this, is the 1/2" 4'x8' foam insulation sheeting even worth fooling with or should I just leave the outer walls the way they are?

Attached are pictures of what it looks like

 

[MBfreak]

Whatever you use, make sure it is fireproof. The fire in London shows how dangerous polyurethane is. To test myself I took some foam doodles I had and they caught on fire immediately from a small match and burned very fast with a horrible smoke.
Hope polyurethane insulation is prohibited in the US. It is in Germany but not in the UK.
+20 people dead!

Ola

 

[gtae07]

I don't think 1/2in of foam will make much of a difference. If you wanted to insulate the walls, I'd almost suggest framing a new false wall, insulate and run more electrical, then sheetrock over.

 

[NUTTSGT]

I'd pull the plywood down, insulate and reinstall the wood trim. Add some paint and you will never know it. It might take some work but will be worth it.

While the 1/2" may not seem like a lot, it will help. Get the highest R-value 1/2" foam available. Before I insulated the back wall of my garage it was bare concrete block and the winter weather would **** the heat right out of the garage.

Like you mention, get the attic (attack) insulated with either blow-in or fiberglass or a combination of products. When I re-insulated my garage attic, I used a combination of fiberglass and foam. You can see pictures somewhere in my Garage Refurb thread in my sig below.

The door doesn't have to be replaced, you can buy either kits to insulate it or buy foam sheets and cut to fit.

 

[64 Thunderbolt]

I'm new to insulation. Where can I find a chart telling me what the "R" values are so I can pick the best?

 

[NUTTSGT]

You can find some of the information by Googling it or if you have a HD nearby, they usually have the R-value listed with the price and SKU. Some insulation will have it printed on it.

http://insulfoam.com/insulation-comparisons/

 

[ItsNemo]

I'd pull the plywood down, insulate and reinstall the wood trim. Add some paint and you will never know it. It might take some work but will be worth it.

While the 1/2" may not seem like a lot, it will help. Get the highest R-value 1/2" foam available. Before I insulated the back wall of my garage it was bare concrete block and the winter weather would **** the heat right out of the garage.

Like you mention, get the attic (attack) insulated with either blow-in or fiberglass or a combination of products. When I re-insulated my garage attic, I used a combination of fiberglass and foam. You can see pictures somewhere in my Garage Refurb thread in my sig below.

The door doesn't have to be replaced, you can buy either kits to insulate it or buy foam sheets and cut to fit.

This, pull down the plywood and insulate with something like Roxul Comfortbatt.

Take the opportunity to run new wiring and anything else you might want behind there. Reinforce the walls where you might hang heavy things too. Fresh coat of paint to brighten up the dingy yellow and you'll feel like you have a whole new garage.

Honestly the time to do it is before you fill the garage with stuff, so spend the extra time and money now.

 

[NUTTSGT]

This, pull down the plywood and insulate with something like Roxul Comfortbatt.

Take the opportunity to run new wiring and anything else you might want behind there. Reinforce the walls where you might hang heavy things too. Fresh coat of paint to brighten up the dingy yellow and you'll feel like you have a whole new garage.

Honestly the time to do it is before you fill the garage with stuff, so spend the extra time and money now.

I'm not sure if the OP can get Roxul in North Carolina. It's just made it's way around here in the last few years after seeing it on Canadian DIY shows for years.

OP, you may want to add a location to your profile. What works for some parts of the country don't work in others.

 

[64 Thunderbolt]

I was checking after he posted that and I can't get get it thin enough in NC. From what I've found on HD website I can only get insulation board in 3 & 3.3 in 1/2" here.
What's should I get? Not a house guy I'm more of a car guy if you know what I mean?

 

[Stuart in MN]

I was checking after he posted that and I can't get get it thin enough in NC. From what I've found on HD website I can only get insulation board in 3 & 3.3 in 1/2" here.
What's should I get? Not a house guy I'm more of a car guy if you know what I mean?

Can you pull off the plywood and then fir out the open space to accommodate the insulation? Without knowing just how the plywood is held up to the wall now, I'm thinking you'd add vertical 2x4s behind it on 16" or 24" centers to create the space.

If the plywood is removed carefully you should be able to put it back up and re-use it.

 

[64 Thunderbolt]

I should be able to remove the strips and then remove the plywood and reuse it.
I have measured the distance from the wall on the bottom and I have about a 1/2" of clearance from the wall so I'm thinking 1/2" sheet insulation should work.

 

[TractorJeff]

OP states its plywood on 2x4 framing already on the outside. I guess I don't understand why he only has a 1/2" to play with?

 

[NUTTSGT]

OP states its plywood on 2x4 framing already on the outside. I guess I don't understand why he only has a 1/2" to play with?

My guess, it's an exterior wall, brick veneer over block maybe ? Furring strips on the block wall and yielding little room, possibly 3/4" and not half inch.

Not sure just speculation.

 

[64 Thunderbolt]

Your correct Eric.
I'm at the beach on vacation and am just going off what I can remember.
If I made the framing out of 2x4's I would lose garage space so I want to keep it the way it is.
I'm reading your "garage refurb" post right now

 

[64 Thunderbolt]

the framing must be made out of 1x4's the more I think about it.

 

[PFSard]

If I made the framing out of 2x4's I would lose garage space so I want to keep it the way it is.

Realizing that space is at a premium : I would calculate how much space I would actually be losing before I condemned that possibility.

 

[gtae07]

Realizing that space is at a premium : I would calculate how much space I would actually be losing before I condemned that possibility.

Adding 2x4s (the long way) with 1/2 drywall, on two walls of a roughly 20x20 garage, will lose you about 13ft2 of floor space out of 400ft2. About a 3-4% loss.

 

[NUTTSGT]

If you remove the furring strips and add 2x4s flat. That would give you 1 1/2" for foam and only give up another 1" of floor space. That is how I did my back wall.

These are actually 2x2s.

Added an 1 1/2" of EPS foam....I think it was advertised as an R6.

 

[64 Thunderbolt]

Yeah that might be the way to go.
I think I might start a thread. My plans are when I get back from the beach to tear down that small room which at one time I was going to keep.

I'm starting a major project soon an am trying to get the garage in order before I do. I've already got an electrician schedule to add more eletrical outlets and new lighting.

Eric you and I have a LOT in common. I've been a Ford guy all my life but I'm changing blood lines. I just bought an all numbers matching 1966 Chevelle SS 396/375 4 speed car & am starting on a complete frame off restoration