# Finishing and insulating detached garage



## colin83 (Nov 20, 2018)

Hello,

I'm going to be insulating and finishing the ceiling of my detached garage this winter. My wallet and wife would like me to do this all myself. I am fairly handy just lack the knowledge of material selection. I'm in Washington state so it's wet here. We have mild summers but a few weeks in the 90's and a few weeks below 30. I'll be using half the space to kennel my Labradors, thus the noise concern.

So my priority for insulation selection is price, sound deadening and then heat retention. I'm not a total cheap skate but cost is a limiting factor. My local stores carry common Batts that I've seen used in the past but am considering using polystyrene boards as I'm thinking these may reduce sound transmission a little better.

The roof trusses are 2x4 construction. I'm assuming that any insulation beyond the 2x4 vertically is essentially useless. Please correct me if that is incorrect.

Will I need to install soffit baffels if I use poly board insulation? Anyone have feedback for me on my plan?

Is there a need to spray foam seal the poly boards? Or just cut and place? 

Sent from my Pixel 2 using Tapatalk


----------



## Nealtw (Jun 22, 2017)

Can you post a picture most trusses are not designed for any room above the ceiling to be finished.


----------



## colin83 (Nov 20, 2018)

If I understand your concern I won't be creating a loft or attic just insulating the ceiling and hanging sheetrock. Is that what you meant?

Sent from my Pixel 2 using Tapatalk


----------



## Nealtw (Jun 22, 2017)

colin83 said:


> If I understand your concern I won't be creating a loft or attic just insulating the ceiling and hanging sheetrock. Is that what you meant?
> 
> Sent from my Pixel 2 using Tapatalk


 Unless you can build a floor that is not supported by the trusses, you are usually out of luck.


What are the measurements of the garage and direction of the trusses.
This one is made for storage.


----------



## colin83 (Nov 20, 2018)

Nealtw said:


> Unless you can build a floor that is not supported by the trusses, you are usually out of luck.
> 
> 
> What are the measurements of the garage and direction of the trusses.
> This one is made for storage.


Shop is about 30'x25'. Trusses span the 30' section and originally built with no weight bearing wall down the center of the garage but there is one that was added by previous owner. 

I'm not looking to add a floor in the trusses. I want to insulate the ceiling and add sheetrock. Sorry I'm just not following how your questions are relevant? Are you concerned that the sheetrock will be loading the trusses in a way that they were not designed for?









Sent from my Pixel 2 using Tapatalk


----------



## Nealtw (Jun 22, 2017)

colin83 said:


> Shop is about 30'x25'. Trusses span the 30' section and originally built with no weight bearing wall down the center of the garage but there is one that was added by previous owner.
> 
> I'm not looking to add a floor in the trusses. I want to insulate the ceiling and add sheetrock. Sorry I'm just not following how your questions are relevant? Are you concerned that the sheetrock will be loading the trusses in a way that they were not designed for?
> 
> Sent from my Pixel 2 using Tapatalk


 Sorry I thought you were asking about room above. 
For the ceiling you want Air chutes to allow air from the soffits into the attic space and a few box vents or a ridge vent to let it out. You best bet is blown in loose insulation after you do vapour barrier and drywall. You would like to have 12 or 13"


----------



## colin83 (Nov 20, 2018)

Would I need soffit baffles if I use poly insulation or traditional Batts?

Sent from my Pixel 2 using Tapatalk


----------



## ddawg16 (Aug 15, 2011)

I wouldn't insulate the underside of the roof. Keep it simple.

Put up drywall (sheetrock) on your ceiling. Your trusses should be able to hold the drywall just fine. I'd use 5/8" fire rated. If you can get a buddy to help, it will be a lot easier. And if you use 12' long sheets...less seams.

I did all my drywall by myself....

At one end, make an access hatch.....maybe even add pull down stairs. If it was me, I'd be putting down plywood down the center of the garage so you have something to walk on.

Once you have the drywall up....just use R-19 batts....if you want to go real cheap...go rent an insulation blower and do blow in.

Side note....you might want to evaluate your lighting plan.....I personally like recessed cans. The ground level of my garage has 18 of them with LED's.


----------



## colin83 (Nov 20, 2018)

Pull down stairs were delivered yesterday. Any issues with putting insulation thicker than the 2x4 truss?









Sent from my Pixel 2 using Tapatalk


----------



## ddawg16 (Aug 15, 2011)

colin83 said:


> Pull down stairs were delivered yesterday. Any issues with putting insulation thicker than the 2x4 truss?
> 
> 
> 
> ...


Non what so ever.....done all the time

If you put up a walk way, just compress the insulation under it.

I assume you are doing the walls as well? Just make sure you do the ceiling first. The wall drywall helps to hold up the edges of the ceiling drywall.


----------



## Nealtw (Jun 22, 2017)

If you are not using the space up there you don't want a pull down ladder. If you do you want to have a sealed door. 
If you add heat to the garage it is the heat off the top of the wall that causes Ice dams in cold zones so you want air chutes and vents.


----------



## APA (Jul 13, 2018)

Detached garage? I would just staple some r-19 batts to the 2x4s from below then screw 1/2" sheet rock over that. I's wait until i needed access to cut the access door. Not sure if you are getting this permitted though.


----------



## ddawg16 (Aug 15, 2011)

APA said:


> Detached garage? I would just staple some r-19 batts to the 2x4s from below then screw 1/2" sheet rock over that. I's wait until i needed access to cut the access door. Not sure if you are getting this permitted though.


Unless you live in Chicago, I can't imagine why you would need a permit


----------

