What thickness of insulation for garage ceiling

[BADBOY]

Was wondering what thickness of insulation do you use in ceiling of garage. Do you use the same as trusses or go thicker, if its 2x4 truss use 3 1/2" insulation or go to a 5 1/2" thickness.Was quoted a r40 which is 11" thick which I thought was totally wrong, or am I wrong. Any thoughts or suggestions would be greatly appreciated.

[cowmanbob]

I did mine in R40.

[buzzard]

R 40 minimum, if you have the space above the ceiling joist.
Did my shop R 50.

[BADBOY]

So it is r40, I thought the guy was yanking my chain when he said that, r40 it is.

[bucksnbears]

Insulation is cheap.
16"

[liar]

Originally Posted by bucksnbears

Insulation is cheap.
16"

x2
i extended the insulation stops and filled the attic space. 2.5 to 3 feet of blown in pink fiberglass . in the summer it feels like a walking into a cooler on hot days .

[mmhmmmm]

Yup he is right with the r40. Blown in we do r60. Although r60 and a above ceiling sag becomes a concern.


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[250mark1]

did R50 blown in insulation in my garage price difference between having R40 and R50 was about $85.00

[ChickakooKookoo]

I just finished mine with the R40 batts, yup about 11" thick. Honestly, now that I'm done, I would have gone with blow in.

[dicknormal]

Originally Posted by liar

x2
i extended the insulation stops and filled the attic space. 2.5 to 3 feet of blown in pink fiberglass . in the summer it feels like a walking into a cooler on hot days .

Did the same with mine in a non heated garage. Cool in the summer and has not got below 8c in there over 3 winters. The heat from the truck engine keeps the chill off and the water dripping off in the winter has never frozen on the floor.

[Sneeze]

There comes a point where more insulation works against you.

Dont cover the tops of the insulation stops. Further you want enough space above for air movement. If the soffit isn't vented get out your saw.

You could end up with a garage that stays nice and cozy in the winter but goes to +50 in July.

[Grizzly Adams]

Originally Posted by ChickakooKookoo

I just finished mine with the R40 batts, yup about 11" thick. Honestly, now that I'm done, I would have gone with blow in.

x2. better coverage and not that difficult, cheaper as well.

Grizz

[BEL]

What would it cost, ballpark figure, to have insulation blown into a ceiling? Say, average sized house. BEL

[ChickakooKookoo]

My garage is 24 x 24. I spent right around $900 on the R40 batts buying them at $75/bag (6 batts) from Home Depot. I was told after that I could have had blown in done for $700-800. That number came from my neighbor who is a construction manager for a commercial contractor.

Never again will haul batts up a ladder!

[bucksnbears]

Sounds about right.
And if newer truss design, and 2' oc,. 2 people can have that done in 2-3 hours.

[liar]

Originally Posted by Sneeze

There comes a point where more insulation works against you.

Dont cover the tops of the insulation stops. Further you want enough space above for air movement. If the soffit isn't vented get out your saw.

You could end up with a garage that stays nice and cozy in the winter but goes to +50 in July.

i dont know that too much insulation will " work against you " if the trusses are on 24" centers you need to be aware of the weight of the insulation and sagging of the ceiling , as previously mentioned . and i agree , air flow is critical , which is why i extended the insulation stops to insure that the openings did not get plugged .

[BADBOY]

Insulation stops and rafter vents is that what you are referring to, those are the same, no or am I missing something

[trailraat]

If you go with blown in just remember if you have to do any work up there ever it will be hellish. I have blown-in in my house on top of batts, I spent a good chunk of time up there installing some pot lights and other wiring, the insulation made a bad job aweful.

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[liar]

i dont know if " insulation stops " is the proper name . they are usually made of cardboard and fit between the trusses . they keep the insulation from protruding past the edge of the exterior wall and go up and follow the underside of the roof sheeting , keeping an air space of about one inch . this allows air flow through the vented soffits into the attic space and out the ridge vents . the optimum temperature in the attic is the same temp as outside . unrestricted air flow ensures this .

[overhere]

I think the term is moore vents . And i have r50 in my garage. Nice in summer ( cool) and warm in winter.

[BADBOY]

So with the blown insulation, do you need to block the soffits as well as put in rafter vents, or what do you do at the truss ends

[Fish along]

Originally Posted by BADBOY

So with the blown insulation, do you need to block the soffits as well as put in rafter vents, or what do you do at the truss ends

No you don't block the soffit,air flow has to come from the soffit into the roof cavity,the temperature in the roof cavity should be the same as outside,its also a good idea to have vents in the gable ends for extra ventilation,depending on your roof type that is. And yes you have to install insulation stops.

[BADBOY]

So whether you stuff batt insulation or block it with wood, anything will do but as long as you have rafter vents in place correct. As long as no loose insulation gets into soffits.

[bucksnbears]

Nailed it!

[Grizzly Adams]

Originally Posted by BADBOY

So whether you stuff batt insulation or block it with wood, anything will do but as long as you have rafter vents in place correct. As long as no loose insulation gets into soffits.

Preformed insulation stops should be amply long enough to extend past the insulation, either way. In the old days, we just nailed a piece of plywood in place to keep ir out of the soffit.

Geizz

[Big Grey Wolf]

Guys, I can understand R40-50 insulation in your home but have hard time understanding why you would need it for area you may heat for few hours to change air filter on your truck. R20 would be more than sufficient for temporary work space.

[dicknormal]

Originally Posted by liar

i dont know that too much insulation will " work against you " if the trusses are on 24" centers you need to be aware of the weight of the insulation and sagging of the ceiling , as previously mentioned . and i agree , air flow is critical , which is why i extended the insulation stops to insure that the openings did not get plugged .

24" center and no sagging when you finish the interior with metal.

[Grizzly Adams]

Originally Posted by Big Grey Wolf

Guys, I can understand R40-50 insulation in your home but have hard time understanding why you would need it for area you may heat for few hours to change air filter on your truck. R20 would be more than sufficient for temporary work space.

20 is all I have in mine, you can always upgrade.

Grizz

[Glion]

Go r50 right away... cost difference isn't that much and to get someone later is a pain.

[BADBOY]

Diffenately going r40 or 50, when spring rolls around, thanks for all the suggestions, greatly appreciated