garage insulation

[that-guy]

I'm about to buy a house with a detached 2 car garage that is stick built and never taken any further. I am going to want to insulate it and finish the inside shortly after moving into the home. I would like to use spray foam as it is said to be one of the best ways to insulate these days. I also know that it is very expensive to have a professional company come out and do it for me, but I am the type to do most everything on my own. So I was wondering if this kit from Lowes is any good, or if there are any kits out there that any of you could suggest for me? thanks in advance

edit: can't get the link to work, but its on Lowes.com, its their Touch 'n Foam Professional Pro System 600 Foam Sealant

 

[that-guy]

like 70 views and no one has any input?

 

[sublimate]

Your link doesn't work (which may partially explain the lack of replies, but see below) so I don't know what kit you are referring to, but in general I think they would be more expensive since you're not buying in bulk.

I looked at doing foam on my build but decided it wasn't worth the extra cost since I didn't plan to keep the garage near as warm as you'd normally keep a house. The cooler you keep your garage the less benefit there is to higher insulation.

I ended up going with blown-in cellulose since it has the highest mass and so blocks the most sound. That was important to me since sometimes I like to wrench at night and don't want to wake the wife or neighbors up.

like 70 views and no one has any input?

BTW: you'd probably get more replies in the Heating section...

 

[GN4WHLN]

I didn't get anything insulation wise when I clicked on it.
Not knowing where you live, it's hard to say what would be the best approach so I'll tell you what I did with my 2 car attached. I's stick built with stucco exterior and a composite shingle roof. It's southern Calif so it never gets too cold (maybe in the high 20's on the coldest nights) and I have no snow issues. Humidity is not a factor as the climate is fairly arid.
I caulked anything that looked like it needed a seal and used kraft-faced batts (R13) stapled to the studs and covered it all with 5/8 fire rated sheet rock. Of course I had finished all my electrical and plumbing prior to this. The roll up door has foil faced styrofoam and the roof is yet to be insulated. When I do it I'll insulate it at the rafters and not across the cords as I have some storage up there I access periodically and I plan on leaving that space open as part of a future ventilation system.

The garage stays warm as it is. It typically does not drop below 60 degrees. I'm good to work all winter in there and usually don't use any heat. Could it be better? Sure, But for relatively little money, it works well for where I live. The dogs are warm at night, and the cars are not refrigerators when we leave in the morning. I can work all day in there on a cold day with the door down.

 

[NUTTSGT]

like 70 views and no one has any input?

I don't think that many here have much experience with the DIY spray foam kits. In some areas like mine, pro guys with spray foam experience are just making a name for themselves and are still a bit too expensive for some to use.

Once it becomes more a common practice, I'm sure more and more people will try the DIY kits or the big box stores will actually stock them.

 

[moparfreak]

I live in a northern climate (WI) and am pretty pleased with my intial results insulating a rather large space (1350 sqft). I stuffed R15 kraft-faced batts into the garage walls (pretty much the most you can fit into 2x4 walls), and then used R25 unfaced batts in teh joist cavities above the metal ceiling in the attic. Granted we have not yet gotten to the harsh cold part of winter, but since I got the ceiling and insulation up, my garage doesn't really dip below 57-60 degrees or so during the nights, and we are easily seeing 30 degree evenings at this point. I have a 80K BTU heater that I haven't even fired up for the first time and I have good confidence that I should be able to heat up and take the chill out during the dead of winter no problem.

So, in summary:

1) I recommend batting - very easy to install
2) Go with oversized / denser batting, the cost increase really isn't much
3) My total cost for insulating garage was $1060 give or take, so $0.78/sqft. Well worth it, imho. Of course this is purely material cost, since I installed myself.

Thanks,
Adam

 

[72Anthony]

It helps to know what part of the country you are in...cooling, heating or both.

Another option is flash and batt: 1 or 2 inches of spray foam (the flash) followed by traditional batts. It provides the air sealing of foam at a lower price point.

Regards,
Anthony

 

[kv501]

Unfaced batts in the walls, faced batts in the ceiling followed by blown insulation overtop of that. It's going to take you a loooooooong time to recoup the difference in energy cost between the two, and some installers I know say it's less efficient per dollar spent.

 

[WHeidt]

The benefit to spray foam, is that it seals and can act as a vapor/air barrier, but if your garage doesn't leak air or you are going to do drywall (which is also a air/vapor barrier when done correctly) I wouldn't bother with the spray foam. Make sure you don't have any air leaks in your walls. Get a can or two of spray foam to do around window and door frames if you need to.
In case everyone else didn't convince you, let me put some figures to this. You said 2 car garage, so lets say 20'x20'. Assuming 8' tall walls that is 640 sq.ft. of wall. Now if you are 2x4 framed with batt insulation you would do R-15, to match that in the spray you are looking at, you would need 3". This means 160 cubic feet of spray foam, a little over 3 kits worth. $2,066. Or you can do the batt insulation, approx. 10 Roxul 12-Pack 47-in L x 15-1/4-in W x 3-1/2-in D 15-R for $394. I didn't figure in doors or windows, but you get the point.

 

[Friartuck]

72 Anthony's comment is on target. A lot of this depends on you telling us where you live. The flash and batt method is preferred by Fine Home Building (Tauton) publications. I assume your going to rock this after insulation. Get some estimates from insulation/drywall installers. You'll be surprised on how quick and reasonable the price. Sometimes it doesn't pay to do it your self.

 

[volleyball]

Make sure the building is square as much as possible before you spray. It will stiffen it up. More so than boards or batts.
Biggest thing is you need a remote air source mask while you are spraying.
Without an insulated slab and door, you won't manage to get a great seal to make the foam really pay.

 

[TrickVert]

Just as a point of comparison, I'm finishing my stick-and-stucco detached garage using R13 batts in the ceiling and walls. With only the ceiling insulated (and not yet completely covered with 29-gauge corrugated metal) I've already noticed a significant difference in comparing above-ceiling and below-ceiling temps. I did not go nuts sealing it with added vapor barrier, caulking, etc. The garage will only be heated for occasional projects, and not 24/7. This, and the fact that I have attic storage above the 2x4-constructed trusses resulted in the R-13 decision. YMMV

Andy

 

[that-guy]

sorry for not getting back to this till now. the house is in Eastern VA. gets in the single digits sometimes during the winter, so I want to keep as much heat in the garage as possible. I am thinking that spray foam may not be the most cost effective solution. it is built with 2x4's 16" on center, so what rollout or bat insulation would be recommended for my needs?

 

[kbs2244]

I would suggest doing it the same as the pros do houses in your area.
I would expect 4 inch, Kraft faced bats with poly vapor barrier on the walls.
Vapor barrier for the ceiling seems to depend on how humid your winters are.
Either way, if you put in a ceiling, you will need to vent the attic the same as a house.
(Eves and ridge.)

 

[LsFarm]

The 'flash' and fiberglass is the way to go. It doesn't take much of a wind to create a lot of cold air infiltration into your heated garage.
The spray foam seals the 2x4's to the exterior siding, plywood, 1"x's, or the worst: Lap siding. The foam SEALS the wall, no more air infiltration.
The unfaced fiberglass bats fill out the wall airspace, and then your drywall or other wall covering.

I did not have the $$ to spray foam my shop when I first moved in. It is pole barn construction. For the ceiling I used 2" foam board with a layer of aluminum reflective on the inside side. The boards are 4'x12'. And for the walls, I cut and inserted 1.5" foam between the purlins, and behind the posts.
While the insulation helped, there is still a lot of infiltration around every exterior plywood seam and joint. When the barn would hold 50* on a 30* calm wind night, if the wind was 10-15mph with the same temperature, the shop would be only 35* in the morning.
I've learned that a small amount of infiltration will negate a LOT of insulation.

So, I had the exterior walls given a thin, 1" layer of foam, that went over the foam boards, sealing the inside wall surface to the posts, poles and purlins. The gaps between the ceiling boards had widened over the years, who knew that white foam-board shrinks ?? Anyway the gaps were sealed as well as all the light fixture boxes.

NOW, the wind can blow, and there is almost no change in inside temperature between a windy or a calm night. I still have some leaks around the rollup doors, but I'm working on that.

I would NEVER build any heated structure in a cool to cold environment without spray foam sealing the walls.

The '600' kits that I have used are 600 board feet of foam, if the temperatures of the foam chemicals are properly controlled. These kits cost about $600 each. I used 'Green-It' foam products from the chicago area. Also used to be a 'Tiger Foam' company in Pa I think. Google is your friend.

Energy costs will not go down, so whatever insulation you install at this time, will continue to pay you back year after year.

Lsfarm

 

[volleyball]

The problem with doing what pro's do is that they are driven by what they have been doing as they can do that quicker. Not many pioneer new technology. It is a harder sell.

LsFarm, did you tape the foam board joints? Sound like you did not. My house has foam sheathing and it was not taped. And on the worst side the wind would blow in and make the house uncomfortable. I ripped off the siding and foam on that side, put in new boards, taped seams, reside and it has been amazingly different.

For those using the DIY spray foam kits, are you using a supplied air mask? Breathing the gassing is some nasty stuff.

 

[ms fowler]

Sorry to sound a discordant note, but I disagree with Moparfreak's idea of jamming in extra insulation. It MAY help deaden noise, but it will actually insulate less well than R11 or R13 in a 2X4 wall. The reason is that what insulates is AIR; trapped air. The more trapped air spaces, the better. When you over-stuff the wall, you have less trapped air, and more thermal conductivity from fiberglass thread to fiberglass thread.
If you doubt this, ask you local building inspector, or watch a professional insulate a house---they will cut the vapor barrier and remove some insulation from behind every outlet box. This is to avoid packing the insulation in too tightly behind the box.

First time I inspected a house done with the blown-in cellulose, I was amazed at how quiet it was--almost tomb-like.

 

[theoldwizard1]

DIY spray foam is still expensive. The safety gear is a MUST or you can get seriously hurt. A clogged gun could ruin a lot of chemical.

What is more common these days is 2" of spray and then fiberglass insulation.

 

[that-guy]

okay, so I'm sold on fiberglass insulation, most likely R13, as there is actually a few rolls laying the rafters of the garage when I went back to look at it this past weekend...now my question is, should I put up a vapor barrier?

I live in Eastern Virginia. the summers can be pretty humid and get in the high 90's to low 100's, and the winters are sometimes questionable. it can be single digits for days at a time, and sometimes it can be in the 40's. from a few flurries, to 6-18 inch snow falls. very inconsistent in this area.

as a note, I will also be heating this garage with a wood stove with a row of ducting along the ceiling for even distribution

 

[toolmiser]

Have you thought about using a different "batt" insulation that doesn't allow air penetration like "filter glass". For a garage that might be the best of both worlds.

 

[that-guy]

Have you thought about using a different "batt" insulation that doesn't allow air penetration like "filter glass". For a garage that might be the best of both worlds.

please post a picture or link of what you talking about

 

[kelpaso1]

Regardless of what type of bat insulation you still need a poly vapor barrier on walls and ceiling and all seams and electrical boxes tuck taped. Even if your not going to heat the garage right now you may or someone else may down the road. Better to do it right for the $25 it takes in poly and staples.

 

[ihrescue]

I live in a northern climate (WI) and am pretty pleased with my intial results insulating a rather large space (1350 sqft).

Very helpful response Adam.

 

[Nowater]

You can almost match the air sealing of adhesive foam by using common construction adhesive from a caulk tube. Run a 1/4 " continuous bead along both sides of every stud, sill, and top plate. Then seal doors and windows with canned spray foam.

How do you plan to air seal the vehicle door?

Insulation won't do much if the air just blows in.

 

[CNGsaves]

+1 on comments of air-sealing first before you proceed with insulation (ie caulk all gaps, foam all openings, bag outlets like Canada, etc)

Sounds like spray insulation is out-of-budget (both pro or DIY installed).

I'd recommend you use blown cellulose in ceiling as it's cost effective and superior in every way to fiberglass (ie cellulose won't catch on fire like fiberglass, cellulose insulates better, etc). Check out YouTube . . The Big Burn

Search prior GJ threads as there was one where guy did cool netting on walls and blew in cellulose before he put up vapor barrier and sheetrock. I'd follow his lead if I were in your shoes . . . thus blown cellulose everywhere, but AFTER all your rough electrical is completely down, all lighting completely done, all heating systems are planned out (ie black pipe steel for natural gas run ??), all airline systems are planned out (IN wall or surface mount later ??) . . . AND all your air-sealing is done. Good luck.

 

[that-guy]

I only ask about the vapor barrier because I have been reading all over the place about condensation and such building up inside of the wall with nowhere to escape, so a poly vapor barrier isn't needed in some situations in some areas.

I would rather be cold in my garage than to have to replace rotted wood, and damp insulation a few years down the road because what I thought was better for my garage only turned out to be worse.

 

[38Chevy454]

I live where typical winter temps are teens at night and just above freezing daytime. My shop has 2x6 walls with R-19, and then R-38 in ceiling. Full wrap on outside, with stucco. I put OSB on walls and caulked all seams and around outlet boxes. It is quite air tight and never gets below low 40's in the shop, even without heat for a week or more.

I agree air infiltration is key, limit this first. Then insulate as much as you can.

Also condensation is caused by temp differential and having good sealed up and insulated structure will be much more moderated temp swings. So less condensation issues.

 

[that-guy]

in what way could I ensure proper ventilation so that the moisture can escape when using a vapor barrier?