garage insulation tips

[sardo_67]

Insulation is done, now onto floor ideas


see last post plz rather than starting a new thread






bought a house with an attached 24x24 garage no insulation or ceiling so open to the rafters.

HS Tarm MB55 is in the garage along with a 60k BTU Modine heater as a blow off circuit/garage heater I almost have up and running. Plan on doing a lot more garage stuff as I weld and work on my own vehicles as well and hate being cold.

along the one wall that my house is on I put 5/8" sheetrock up and regular insulation so I am looking for ideas on doing the rest of the garage.

should I put a ceiling in at like 10ft and insulate that or leave it up to the roof (20ft at peak) as well as the garage doors which I am not sure about insulating that.

 

[Jeremy8916]

bought a house with an attached 24x24 garage no insulation or ceiling so open to the rafters.

HS Tarm MB55 is in the garage along with a 60k BTU Modine heater as a blow off circuit/garage heater I almost have up and running. Plan on doing a lot more garage stuff as I weld and work on my own vehicles as well and hate being cold.

along the one wall that my house is on I put 5/8" sheetrock up and regular insulation so I am looking for ideas on doing the rest of the garage.

should I put a ceiling in at like 10ft and insulate that or leave it up to the roof (20ft at peak) as well as the garage doors which I am not sure about insulating that.

Are you ever going to put a lift in? If so the ceiling being 10ft high may not work. If it does work then I'd put a ceiling in at 10ft and insulate it with cellulose blown in insulation. For the walls, depending on distances between other buildings, I'd use roxul in the walls and truss core. The last time I priced it out local to me it was cheaper than vinyl coated plywood, and has probably the lowest installed labour cost. I'd probably put truss core on the ceiling too. Obviously vapour barrier appropriately, install blocking and what-have-you. Electrical can be surface mointed with pipe, or romex in walls. Lift doors are the same price insulated or not in my area, so we just use insulated ones. They're a lot tougher

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[sardo_67]

it's an A frame roof so I can't put a lift in anyway.

 

[moey]

Id vote for a ceiling. Build a platform ontop of a insulated ceiling so you can use the space for storage. 24 * 24 is a lot of space to not put sometype of platform. Add a attic hatch or something similar that a regular attic has so the space is sealed off. I would not worry about the garage doors as long as they are sealed. I have insulated doors on my garage Im sure they make a difference but the big difference is not having huge gaps around it when it closes.

You could get spray foam put on the rafters probably cost less then you think. Worth getting a quote for it. You dont have to worry about making sure everything is sealed perfect if you put a ceiling then.

 

[sardo_67]

that is my plan, there are 2X6s by 20ft running side to side at 9ft or so 4ft on center. my plan was to put 2x8s 16ft long 16 on center to match the roof supports and raise the roof to 10-12ft, throw down roxul then press-borad and vertical ties to the roof for more of a truss effect and have some light storage there with slat vents front and rear same as my house.

i also was thinking about the spray foam on the roof as no one will see it and it's just a garage, my only concern about too much insulation is in the summer it may be 130 in there lol

pic of my house from an old listing. you can see the garage now, i really wish the roof went the same way as the house or was at least a barn or oxford shape roof for more room

 

[moey]

I would strongly encourage you to get a quote for spray foam on the rafters. Our garage is 28 * 28 with a bonus room so its a bit higher. The floor was done with batts not done very well either. I got a quote for spraying the floor I was surprised it was not much more then doing it with roxul like in the 100s of dollars difference not thousands. Batts are less expensive.

You can add vents if heat is a issue. I lived somewhere where the garage was not insulated and it was very hot in the summer and very cold in the winter. The insulation will help moderate that I dont think it will be objectionable in the summer.

 

[sardo_67]

what was done on the floor? I have the typical concrete floor that is in OK shape for being 50+yr old

 

[moey]

what was done on the floor? I have the typical concrete floor that is in OK shape for being 50+yr old

Sorry I was referencing the ceiling or the floor if your standing on the ceiling . Not the concrete floor.

 

[semipro]

Concentrate first on air sealing rather than thermal insulation. You'll get a better payoff for your efforts. You probably need to seal air leaks at the garage door first.
I 2nd what Moey says, check out how much it will cost to foam the underside of the roof. Whether you have trusses or joists/rafters, that area is great for storage. In general I think drywall is a mistake in a garage. Use OSB or plywood on walls and a ceiling if you end up putting one in and you'll be able to attached things to it more easily than drywall.

 

[Dobish]

a ceiling will make a big difference in keeping it warm. when my dad did his garage, he originally had it all open so he could have some storage on the trusses. After the first winter in Wisconsin, he decided that he was going to insulate it and put drywall up, with an oversized access panel. Even without running a heater, it stays a lot warmer in there. When he got the stove cranking, it would really heat up and stay warm.

My last garage used to be uninsulated all around, but after insulating I put up plywood or slat wall so I could use adjustable brackets. I never got around to doing the ceiling, because I had a ton of stuff up in the trusses, but I did cover 1/2 of it with plastic sheeting. I noticed that it helped keep the garage temps more comfortable all year, and the wall connecting to the house stayed a lot warmer. Due to the location of the thermostat, which was directly across from the garage entrance, i saved a lot of money by not having the furnace kick in....

 

[moey]

Yea air sealing makes a huge difference I used to have puddles freeze in the garage in winter with my old garage doors. They were wood and leaked like crazy bad fit all around. I replaced the doors and short of a few tiny holes between slats where they were not manufactured perfect they are great. They are insulated although Im not sure how much the R value makes a difference.

Huge difference no longer have puddles that freeze even in negative temps. Your doors look fairly new make sure you have the rubber seal going all around the frame and good fit at the bottom.

 

[Jeremy8916]

I am a licensed medium density spray foamer, and while I like the stuff, I'd say doing a good job air sealing the ceiling and blowing in cellulose is as effective and significantly cheaper in my market. I get foam at cost and except in the heal, will be using cellulose when i redo my 50 year old house attic. Like has been stated multiple times, air ceiling is the most important. Seal gaps around doors, cover holes, replace windows and what have you.

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[peakbagger]

Put in a ceiling, no sense to heat the attic. Unless you spray the entire underside of the roof, ice damming can become an issue as the heat in the attic will cause snow to melt on the roof, then run down to the overhangs and freeze solid into ice dams. If you put in a ceiling and vent the overhangs into the cold attic its not an issue. You may need to install gable end vents or vent a ridge, plus soffit vents to ensure the attic stays cold and that air flow up through the soffits The soffits leak a lot of air into the building so you need to seal them away from the heated space.Some folks just stuff the ovehangs with insulation which is guarantee that ice damming will occur.

Next thing is replace the garage doors with insulated doors with interlocking seams and resilient edge seals. I used these http://www.wayne-dalton.com/classic-steel-garage-doors-8300-8500. Standard garage doors leak cold air like a sieve and have little or no R value. The difference between a standard door and a good insulated foam core door is night and day.Unless you seal up a standard door with a tarp its the equivalent of leaving a large window open.

Note one thing that a lot of folks dont think about is vapor barriers. A garage that is actively used is a tough application as a snow covered car has lot of moisture in it when it melts.Some of the moisture will end up in the insulationand freeze if the vapor barrier is not perfect and when the garage cools down this can melt ad cause mold. I dont recommend cellulose for insulation in this application. Closed cell foam doesnt absorb water, fiberglass will hold far less and is preferable to cellulose.

Its highly unlikely that the floor slab is insulated, its going to suck heat out the garage and that is pretty much not easy to deal with unless you replace the floor or pour an insulated radiant slab on top of the existing one. If you go that route, you need special mix for the slab as the salt can really raise havoc with concrete. You can improve things a bit by insulating the edges that are exposed to the outdoors. Ideally you can dig down a couple of feet but just laying 2 to 3 feet of foam down flat and covered with dirt butted up against the foundation can make a big difference.

The other thing to consider is you need to get a cat or be vigilant about rodents and other critters. They love to nest in garage insulation.

 

[Jeremy8916]

Closed cell foam doesnt absorb water, fiberglass will hold far less and is preferable to cellulose.

This is my only real issue with your entire comment. Its a toss-up which insulation material is worse if there is moisture laden air entering the wall cavity. Cellulose, while it will absorb water, will wick it away and keep it from freezing over onto an exterior surface. If that happens to fiberglass its will settle out, cellulose doesn't have this issue in either wall or roof cavities. Pair that with fiberglass' diminished performance as the temperature differential becomes greater, and cellulose will always come out on top. The ideal situation however is to build tight enough you don't have this issue, and you won't if there's a woodstove in the garage. The stove will negatively pressurize the space and draw in dry outside air instead of moist air being pushed out.

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[semipro]

The other thing to consider is you need to get a cat or be vigilant about rodents and other critters. They love to nest in garage insulation.

In my experience yet another reason to foam the underside of the roof and air seal things up, including the soffits. Mice love fiberglass and cellulose insulation. Some insects can cause problems with foam but I'd rather deal with that than mice.

If you want some sort of ceiling you can still foam the underside of the roof and install a ceiling with attic access via pull-down stairs or such.

I've never found myself wishing I had less storage area, especially in my garage.

 

[peakbagger]

Many years ago I got blamed for a ceiling collapse where someone had insulated it with cellulose before they had fixed roof leaks. The cellulose soaked up the water and weighed down the plaster ceiling until it collapsed. I had nothing to do with it but had predicted it would happen. I have never been a fan of it since. I have seen similar situations with fiberglass and the water flowed through it rather than soaking it up.

 

[Jeremy8916]

Rodents will chew through foam as well. I've been in barns that had rat highways in the foam. So many you could hear them scurrying around. I'd hardly blame a ceiling collapse on an insulation system, cheaping out and not keeping up with home maintenance gets very expensive if you're unlucky

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[sardo_67]

i have a cat, we call her "murder cat" as she leaves at least 2 mice a week dead in the driveway or breezeway area for us so i'm not at all worried about the mice, she's crazy about them. we let her our year round, even last week when it was down to -5*f she wanted to go out.

the doors i have on there are newer but the rubber sealing strips around them have become brittle and cracked, bottom rubber strip isn't bad though, windows are new retrofit double pane in the past 10-12yr or so and along with the back walk in door insulated. the back door is better than the one going into my house actually since it's thin wood with single pane windows on it which sucks as i can feel the cold coming thru into the kitchen.

i plan on adding insulation panels to the inside of the garage as well as sealing up the gaps between them.

does anyone know what a roll up style door costs that is insulated? i'd like to get rid of the overhanging door rails but i think that may be unavoidable without spending like $4,000

 

[gzecc]

I would put in ceiling then install fiberglass insulation. Keep up on any cracks to keep out mice. Garage doors must be well fitting.

 

[sardo_67]

wet filling?

 

[sardo_67]

ok i had a sprayfoam guy come and look at my garage, rough guess is 2300-3000 to spray foam my garage depending on foam type and depth of foam for R value.

does that seem like a good price?

he is working up an official quote for me and i'll get an email later today.

 

[peakbagger]

That sounds cheap for the square footage. My guess is at most you are getting a sealing job more than full insulation of the wall cavities. Just doing the sealing will make a big difference but if the foam is not thick enough you could get into dew point issues in the wall cavities.

FYI definitely discuss how fireproof the foam is. Most household foam is not fireproof and can not bee used in occupied areas without a suitable fire barrier (sheetrock).

 

[sardo_67]

he said 5" will get over the due point, it is just as fire rated as rocksol or any other insulation, i would need to cover it for code reasons or put in a cheap plywood cieling on my rafters which i plan on doing anyway.

i am doing the walls myself with Rocksol and 5/8" sheetrock with some calk or can spray foam on the cracks.

this is on the back burner for sure seeing as my kitchen isn't 100% done and my house doesn't have wall insulation, he gave me a quick 3k or so quote for blow in insulation from the outside of the house for the outer walls as i'll probably do that first.

 

[semipro]

he said 5" will get over the due point,

That he said this is a good sign. At least he understands that insulating to the thickness required to keep the foam's inside surface above the dew point will keep condensation from forming inside your walls.
You'll probably like working with Roxul. I much prefer it to FG.

 

[sardo_67]

haha oh ya i didn't talk to some random cheap guy i found off CL, local company, a little higher cost than some he says but prides himself on the cleanest and most efficient install he can do.