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Advice on insulating my garage


pkschul's Avatar
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09-26-17, 04:54 PM   #1  
Advice on insulating my garage

Hi. First post here. I have a split level home where approximately half of the lower level is a two car garage. The outside walls are concrete. I am in the process of installing an electric heater so I can work in the garage in the winter. I have long wanted to do something about insulating the concrete walls but I don't want to lose much interior space. I was thinking about just installing some rigid insulation and sealing all the gaps. There's just not enough room to do a full framed wall. What do you think would give me the best bang for the buck? The concrete is partially below grade along the back wall. Would I need a vapor barrier? I'm attempting to attach pictures. Sorry they were taken at night.

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Last edited by PJmax; 09-26-17 at 07:14 PM. Reason: reoriented pictures
 
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09-26-17, 07:59 PM   #2  
With any insulation project it is the first layer that makes the biggest difference. Add 1" rigid (r-5) to bare concrete and it makes a big difference. Add that same 1" to an already insulated (r-13) wall and it is a waste of money (almost).

One issue with rigid foam insulation is the need for a fire rated thermal barrier, usually 1/2" drywall. One brand has been tested and approved to be left exposed without an additional covering, Dow Thermax. It is hard to find and a bit more expensive, but it eliminates the drywall.

Some details to work out, but rigid insulation would involve the least amount of space as you stated. You might be able to glue the rigid to the foundation and after it is solid glue the drywall to that. Add a few fasteners through to the concrete to be sure and done.

Bud

 
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09-26-17, 11:47 PM   #3  
Go add up the cost of the rigid insulation vs a simple stud wall with insulation and there wont be a big difference.

Granted you will give up a few more inches, but the stud wall with R13-19 will be the most efficient, look better, and give you a lot of space to easily hang items .

 
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09-27-17, 08:52 AM   #4  
Thanks for the responses. What about going with a narrow framed wall? 2x2 studs? Whatever I end up doing should I seal the concrete with paint first?

 
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09-27-17, 02:16 PM   #5  
narrow framed wall? 2x2 studs?
That would work, you could add firing strips to the wall and insulate between then drywall, it will all work.

No requirement/benifit to do anything to the floor,

 
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09-27-17, 04:08 PM   #6  
Thanks. What are firing strips?
When I said paint the concrete, I meant the wall not the floor. Does there need to be a vapor barrier?

 
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09-28-17, 03:58 AM   #7  
Firing strips, 1x2 material attached to the wall directly, then a sheet of insulation then another firing strip.

No vapor barrier, different situation, external wall no moisture.

 
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09-28-17, 06:46 AM   #8  
Also known as furring strips

 
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09-28-17, 06:56 AM   #9  
Do you plan to use surface mounted receptacles? If not you need enough depth for the boxes.


I can explain it to you, but I can't understand it for you.

 
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09-28-17, 07:44 AM   #10  
Thanks again for the advice. I'm not planning to add any more electrical outlets than are already present... I have a few already installed in the ceiling. I just saw this video on youtube and it looks like the perfect solution. Hopefully I can get started this weekend. I'll try to remember to post some pics...
https://www.youtube.com/watch?v=oKQd...YCEk0ZQ4gP0RlA

 
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09-28-17, 07:53 AM   #11  
I just thought of something.. I want to install peg board to the back wall... Not sure if those furring strips on the outside of the foam insulation will end up being good to hang stuff from. Maybe I'll add some 2x4 studs placed against the wall "sideways".

 
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09-28-17, 11:11 AM   #12  
I have a few already installed in the ceiling.
Garage receptacles must be GFCI protected. If the height is more than 6'7" the GFCI protection can't be on the ceiling. It must be a wall receptacle, wall mounted deadface, or a breaker.


I can explain it to you, but I can't understand it for you.

 
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09-28-17, 11:47 AM   #13  
The house was built in 1979. I haven't changed anything since I bought the house in 2002. Not planning to rip it out now. Passed inspection before I bought the house. Nothing noted by my home inspector. Pretty sure what I have is legit.

 
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09-28-17, 11:59 AM   #14  
If you plan to hang anything from the walls, I would not orient the studs sideways.

 
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09-28-17, 03:16 PM   #15  
Also known as furring strips
Fur: is the hair covering of non-human mammals

Fir: is any genus (Abies) of north temperate evergreen trees

So I know what I'm hanging my drywall from!

 
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09-28-17, 04:30 PM   #16  
Passed inspection before I bought the house.
Their love of money often exceeds their expertise. You should not rely only on anything they say.


I can explain it to you, but I can't understand it for you.

 
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09-28-17, 07:47 PM   #17  
Well like I said the electrical has been that way for at least 15 years and likely closer to 35 with no issues. I'm not here to make a bunch of more work for myself.
As for not orienting 2x4 studs sideways then I guess I could use 2x2 studs. Remember I'm trying to conserve interior space.

 
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09-28-17, 11:12 PM   #18  
Any NEW electrical work must comply with the current code enforced in your jurisdiction. It does not matter what the code was at the time of the original construction. Generally speaking, the closer you are to a large population center (inside city limits) the higher the likelihood that a permit and inspection will be required for any electrical work.

 
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09-29-17, 11:46 AM   #19  
Posted By: Marq1 Fur: is the hair covering of non-human mammals

Fir: is any genus (Abies) of north temperate evergreen trees

So I know what I'm hanging my drywall from!

Haha well I've seen some pretty hairy boards in the lumber yards around here but pretty sure that's not why 'furring strips' is spelled the way it is.

 
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