I have a shingle/brick and vinyl siding garage, about 25 x 50ft.
There are 1/2" blue foam sheets on the walls, but with plenty of gaps.
The ceiling is NOT insulated, and there are 6-8 roof vents.

I like the idea of spray foam insulation, as it seems that the coverage would be very thorough.

I asked a company how much it would be to foam my GAR, and the estimate was about $4500.

Questions:
1) Is it possible for me to do the spray foaming myself?

2) Are there companies that rent the equipment for spray foam insulation, and where do I get the chemicals?

3) Is it worth the trouble?

4) If I spray the ceiling/roof, I guess I should close off the soffit vents as well as the 8 (or so) roof vents, right?

Appreciate any thoughts on this. Thanks in advance

 

home depot sells a kit alot cheaper
you have to go to contractor section and ask for it
its a two part system

 

We used this at the old garage I used to work at and it was pretty easy to do.

 

I own a spray foam business! Yes you can buy the kits and do it yourself. It will cost you the same for materials as it would be to pay someone else to do it that knows what they’re doing! Yes to closing off ridge and soffit vents!

 

Two things to consider....... 1 if you spray foam the entire garage, you wiil trap any and all moisture in the garage. 2nd... make sure any plumbing, electrical or anything in the wall cavity is in place. If they are not or you have to ad a wire or plumbing, etc now you have to cut the foam out of the way. Same if you have electrical or plumbing problems...

 

There's a thinner spray that is used commercially to cover boilers. You can literally put your hand on a hot boiler once it's been covered. I've forgotten the name of it. But if you know anyone in commercial passive fire protection, they'll know what it's called.

 

youll get your 4500 back in heating and cooling savings bro.

 

Those soffit vents and roof vents are there for a reason.
you have to treat your garage like a house. if you are going to use a furnace to heat your garage you should have some type of ceiling. Then insulate the ceiling and let the air flow from the soffits to the roof vents.

 

Those soffit vents and roof vents are there for a reason.
you have to treat your garage like a house. if you are going to use a furnace to heat your garage you should have some type of ceiling. Then insulate the ceiling and let the air flow from the soffits to the roof vents.

I’d say pay to have it done and avoid the mess

 

There are lots of different kinds of foam so make sure to get the right kind.

 

I closed off my garage door to make a shop. I used fiberglass insulation. Heard of contractors that did remodeling and cursed foam insulation over the wires and pipes. Consider if you expand or remodel.

 

Assuming closed cell foam at 3 inches thick $4500 is a good price, how much do you think can be saved on a diy?

 

I helped a buddy do his 28x32 pole building. DIY kits. We went roughly 2” and he spent about a grand.


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Problem with fiberglass is critters!

 

Never had that problem in 77+ years.

 

I have 9' celling in my garage (26 x 30). When I retired I insulated it with bats and put up 5/8" OSB on walls and celling as well as installing a pull down ladder and put flooring in part of attic for storage. I had no roof vents so I installed a ridge vent. I was going to put in a Modine, wired the outlet in when I put the braker box in and additional wall outlets/lighting, but decided to just put in a ventless gas heater. Right now my garage is 54 with outside in low 30's. I hardly have it on and have found that with just the big pilot it has keeps garage at 40 unless I open the door a lot. If you do what you are thinking of, a lot of your heat will be at roof level and you will have to install a fan to bring it down to useable level. Think about a insulated celling at rafter height as an option. I bought a drywall lift used to install the OSB, then sold it for more than I bought it for. Win/Win.
Ches.

 

There is several things to take into account, Like homes once you have spray in foam added to walls if you want to do anythig it is added time and cost like adding anything to the walls like plugs, etc. As cutting out the foam even if something low is no easy! As once had to get something up a wall (motion detector wire and could not has to run the wire up inside of a closet. As others mentioned once you do spray anything underneath is covered and when there is any plumbing wiring issues it is not simpe to fix.Not at many have plumbing in a garage buta few might. Not sure easy it wouldbe to cover off plugs and light switches and just remove the covering. Maybe you can avoid these areas if you can direct the foam away? Many tings to consider as is it truly worth that time and cost. Hmoe Depot has a Tool Rental and maybe have the needed materials.Might googlesearch and see what is possible there has to be Utube Videos talking about this as there is many things mentioned on that platform. Alsomentioned is you really donot want to block off soffit and roof vents they are there for a reason to keep ait flow movingand push out any heath during summer months when it gets hot. plus fues from gas and such has a way to get out as a close bldg can holdthese andany spark might be a fire hazard! I wouldsay do your homework researching his. It might be worth knowing before you jump in.
Good Luck!
LFM

 

Do a flash and batt. This is where you spray foam all the edges of each stud bay and any holes, then put a layer of fiberglass insulation on top. The fiberglass insulates just as well and the foam protects from air intrusion and critters. Best of both worlds.

 

I have a shingle/brick and vinyl siding garage, about 25 x 50ft.
There are 1/2" blue foam sheets on the walls, but with plenty of gaps.
The ceiling is NOT insulated, and there are 6-8 roof vents.

I like the idea of spray foam insulation, as it seems that the coverage would be very thorough.

I asked a company how much it would be to foam my GAR, and the estimate was about $4500.

Questions:
1) Is it possible for me to do the spray foaming myself?

2) Are there companies that rent the equipment, and where do I get the chemicals?

3) Is it worth the trouble?

4) If I spray the ceiling/roof, I guess I should close off the soffit vents as well as the 8 (or so) roof vents, right to improve home energy efficiency?

Yes, you can spray foam yourself using DIY kits, but it takes careful prep and proper safety gear. Some suppliers sell the foam kits, like Tiger Foam or Froth-Pak, and in some areas, rental centers offer spray rigs for bigger jobs. It might be worth the effort if you're confident in doing it right, but for a garage that size, the cost and labor can end up close to a professional job, which usually ensures better coverage. If you spray foam the roof or ceiling, you should close off the soffit and roof vents to create a sealed, unvented system and prevent moisture issues.

 

1. Yes, you can do spray foam yourself, especially for smaller jobs or spot insulation. There are DIY kits (like Froth-Pak) available at places like Home Depot or online. But for a space that size (25x50), it’s a big job, and consistency in application is key—so keep in mind there’s a learning curve.

2. Some rental centers do offer spray foam rigs, but it’s not super common due to the handling requirements of the chemicals. Most DIYers go with those two-part spray kits I mentioned. You’ll need proper PPE—respirator, goggles, full skin protection. The chemicals aren’t something to mess around with.

3. Is it worth the trouble? Depends on your comfort with the work and how airtight you want the garage. Professionally applied foam will definitely be more uniform and might include a warranty. Doing it yourself could save money, but you’ll want to weigh that against potential mess-ups or incomplete coverage.

4. Yes, if you're spraying the underside of the roof deck, you're basically turning the garage into a conditioned space. So you'd need to close off all vents—roof and soffit—to prevent moisture cycling and air leakage. Just make sure you’re doing a full coverage spray if you go that route, and consider a vapor barrier as needed depending on your climate zone.

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