Need help insulating garage

[portalkeeper]

I installed a mini split in my garage and want to insulate the garage a bit more than what it is currently to help keep it warm in Winter as well as cold in summer. I live in Denver, climate zone 6b.

The garage has exposed framing meaning there is no no ceiling, just the exposed trusses and ceiling joists. There is one vent on the vaulted roof about 1 ft by 1ft. Less than half of the garage has insulation of mixed brands (but all of it is faced insulation). All the insulation is covered by this 1/8” or 1/16” plywood paneling material (not drywall) to keep the fibers sealed away, except for about 5” below the top plates of the walls. They left the insulation faces open I believe to allow for air and moisture to escape from the wall cavity.

The exterior walls of the garage are brick walls. I’m not sure if it is the traditional double brick type but the wall is definitely two brick depths thick (so I guess this means a double brick wall). The brick is not exposed at all in the interior of the garage. Instead there is some kind of 1/2” brown insulation paneling (at least I think it’s insulation) layed up against the brick with a small gap between it and the brick wall. You can see the small gap and all the excess dried mortar on the back of the brick wall when looking down at the top plates of each wall (when you are inside the garage).

The garage has drywall above the top plates on one of the 4 walls and the same brown insulation material as a backer for siding on the opposite wall (the gable end). The drywall separates the exposed attic of the garage from the attic of a pretty large breeze way that sits right next to the garage (there is no insulation on the drywall on either side).

The garage isn’t exactly detached as the shared roof of both the garage and breezeway **** up against the roof of the home. All three attics are connected via access holes. The garage has a hole in that drywall that leads to the breezeway attic and the breezeway has another hole that you can step through to get into the main attic of the home which obviously has the drywall ceiling under your feet. I’m also building a removable cover for that hole from the garage attic to the breezeway attic.

The breezeway also has a ceiling made of plywood. The only place without a ceiling is the garage which is like to keep that way.

The wall I am mainly concerned about insulation is exactly the wall with the drywall and access hole above the top plates. This wall has exposed electrical and 2x4 stud framing. The studs in the garage sit up against that brown 1/2” insulation board material (which I really hope isn’t asbestos), and as I said behind that insulation board material is the the double brick wall. There is only that one ventilation opening on the roof, there aren’t any ventilation openings on the soffits on either side of the garage, they just have a regular wood fascia and plywood to create the over hang. No vent on the gable end. There is no ridge vent. I went on the roof and checked.

There are a few unknowns to me about insulating brick homes that I would like someone knowledgeable to comment on. One is whether to use faced insulation like they have already used in the other walls of the garage or to use non faced. The other is the r value I should look for. I’ve read brick can crack with temperature swings and would like to avoid that. Another thing is whether to use vapor barrier like plastic film or a smart barrier. Creating a ceiling is out of the question as I would like to keep the truss framing exposed (I have a large air filter for the entire garage sitting in this exposed attic) but I’m open to insulating the roof plywood if insulating the walls turns out to not be enough. So I’d like some instruction on what materials to use if I decide to do that too. Thanks for any help you guys can give me!

 

[mike93lx]

Paragraphs. Please


Put a ceiling in

 

[portalkeeper]

Paragraphs. Please


Put a ce

Paragraphs. Please


Put a ceiling in

Is there really no way to do it without a ceiling?

 

[kngelv]

Pictures would help

James

 

[portalkeeper]

Pictures would help

James

Just added

 

[DaChev]

If you are not going to insulate the ceiling, you would be better off with a heated vest.

 

[Oatmealman]

I'm currently going through the same process. I have tried to figure out every single option. My initial plan was to use 4" dense foil faced poly iso in my ceiling leaving a 1.5" gap as an air channel for the roof to vent. I've now changed my plan to enclosing the ceiling on the trusses and blowing in insulation. It's not how I wanted to do it but It's the only way to get a proper R rating in the ceiling.

In my walls I did dense packed cellulose with insulation netting and osb over that.

 

[portalkeeper]

I'm currently going through the same process. I have tried to figure out every single option. My initial plan was to use 4" dense foil faced poly iso in my ceiling leaving a 1.5" gap as an air channel for the roof to vent. I've now changed my plan to enclosing the ceiling on the trusses and blowing in insulation. It's not how I wanted to do it but It's the only way to get a proper R rating in the ceiling.

In my walls I did dense packed cellulose with insulation netting and osb over that.

Darn I see you caved in to having a ceiling. I’m really trying to figure out a way to do this without having to create a whole separate attic. I’m thinking your initial idea seems like a good option. Is it important to have that 1.5” air gap between insulation and roof plywood even if you have no venting in your soffits?

 

[Oatmealman]

Not as important no, but I’ve got a shingle roof and want it to last as long as possible and minimize the space I have to condition, in Wisconsin we get some pretty cold winters and hot humid days during the summer so insulation is important to make the building as cheap/comfortable as possible to use year round. My roof is currently not vented either but I’m putting a new roof on next year and will put in soffit vents and ridge vent at that point so it can breathe. Without venting in the roof and insulation tight to the roof its gonna bake in the sun and greatly reduce its lifespan if it’s in the direct sun.

 

[Ak Jim]

Not as important no, but I’ve got a shingle roof and want it to last as long as possible and minimize the space I have to condition, in Wisconsin we get some pretty cold winters and hot humid days during the summer so insulation is important to make the building as cheap/comfortable as possible to use year round. My roof is currently not vented either but I’m putting a new roof on next year and will put in soffit vents and ridge vent at that point so it can breathe. Without venting in the roof and insulation tight to the roof its gonna bake in the sun and greatly reduce its lifespan if it’s in the direct sun.

Could you put stringers on the existing roof then another later of plywood and then shingles on that. Basically create a wanted space between the existing roof and a new roof assembly?

 

[kngelv]

I’m not trying to be insulting here, but there’s no way I would cover or insulate any of those walls or ceiling without fixing your electrical wiring. None of that is up to code and some of it is straight up dangerous.

James

 

[mike93lx]

I’m not trying to be insulting here, but there’s no way I would cover or insulate any of those walls or ceiling without fixing your electrical wiring. None of that is up to code and some of it is straight up dangerous.

James

The fuse/breaker box placement is absolutely wild

 

[ipgenie]

It gets pretty cold around here and lots of older block buildings don't have wall insulation, but get by with ceiling insulation. Most of the heat loss/gain is through the ceiling.

Best thing you can do to improve your heating and cooling is to clean up the wiring so you can put in a ceiling with insulation. Seal up any air gaps and if you never get to the wall insulation, it'll still be a lot better. Next step is probably insulation on the sunny side of the building if that isn't already done.

 

[markietas]

I'm a big proponent of getting your workspace thermally comfortable as soon as possible, but there is an order of operations here.

You skipped about 5 steps that should have happened before the mini split install.

At each of these steps you should be thinking of how you are going to air seal Incase you are making an area inaccessible later.

First, for sure is get that electrical sorted out, it would probably be easier to start from scratch, looks like a small space so materials won't be too expensive.

Second, would be installing a ceiling, I don't see what you are really loosing by doing that other than a small amount of hard to use storage. You and a friend could drywall that ceiling in a day for $230 including screws and tape + mud. You don't have to make it pretty right now.

Third, blow in cellulose above ceiling. Probably $600 or so in materials from a home center, usually they will let you rent the machine to blow it in for free.

Fourth, install bat insulation in wall cavities and use can foam to seal up air gaps and insulated awkward cavities. Batt insulation is a lot more diy friendly in walls that blown but that is technically possible.

Fifth, drywall or OSB on your walls. Drywall is easier to get a good air barrier with, again you don't have to make it pretty right now.

Now is where you would normally install the mini split. Since you already did that you will have to awkwardly work around it to do the walls but it is possible.

Also depending on what your siding is, and if it something you can remove and re-install or you are willing to buy new, you can do exterior foam board insulation but that will cost more.

Some people will no doubt mention spray foam everywhere but I am assuming that may be more than you want to spend. At any rate please fix the electrical first if you do that!

Edit: also you should add some real lighting after you do the ceiling.

 

[BurtEggley]

if there is a car or engines run in this space, or you have gas appliances in it, you will want to have some sort of ventilation down low to avoid possible gases building up. You will want the area to vent, natural gas sits low and will flow out side vents. That said, I had a similar situation to you. We made sure the siding was properly installed so there were no water and varmint, insect intrusions, etc., I made sure there were adequate soffit vents, checked all the framing to make sure it would support sheet rock, and we insulated the walls and added sheet rock on all walls with an insulated lift door. The garage stays warmer in winter and cooler in summer, and when I need heat or cooling I dump conditioned air from the house into it. If I was out there enough I would add its own hvac. Once warmed or cooled, it holds temperature well. Also add any electrical, plumbing etc that you may want before you sheet rock. Take lots of photos you can refer to later if you need to add fasteners to the wall or shelves etc.. Best thing I ever did for this house. It also lowered the utility bill because the house shares a large common attached wall with it.