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Insulating vaulted/sloped garage ceiling with trusses

Insulating vaulted/sloped garage ceiling with trusses


  #1  
Old 06-05-18, 09:12 AM
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Insulating vaulted/sloped garage ceiling with trusses

I'm having my garage drywalled in the next few weeks and need to insulate the ceiling. They are scissor trusses, so there isn't much friction to hold the R-30 batts in place. What would make the most sense for installation? I see three options...staple the VB to the trusses to hold them, use metal support wire, or have the drywall guys slide the pieces into place as the sheets are being placed. I'm leaning towards the latter, because it seems to be the most logical choice, especially considering the ceiling is 14' at its highest point, and I don't necessarily want to be up on a ladder holding insulation over my head and trying to secure it in place. They will already be up there, so why not have them do it?
 
  #2  
Old 06-05-18, 11:42 AM
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Insulation installers staple a lightweight netting to the bottom of the trusses or joists to support insulation before sheetrock is installed.
 
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Old 06-06-18, 08:51 AM
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Okay, but this is something I'd like to do myself. Would either of the other options I mentioned be viable?
 
  #4  
Old 06-07-18, 03:00 AM
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Have you talked to the drywall folks about doing the insulation & vapor retarder? Around here,most would say no or they'd sub out the insulation. I've insulated (and rocked) vaulted ceilings and it sure is no fun. And that was when I was a lot younger.
 
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Old 06-07-18, 05:30 AM
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I mentioned it to them when I was getting the estimate and they just looked at me kind of funny. We didn't spend more than a few seconds talking about it. Seems like it would be pretty simple to have them slide a 4' piece of batt in place after they install each row of drywall.
 
  #6  
Old 06-07-18, 05:41 AM
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Don't you use a poly vapor retarder in your area? You put up the insulation and cover with poly (stapled) as you go. The poly holds up the insulation.
 
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Old 06-07-18, 06:22 AM
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I can imagine their funny look... wish i knew what they were thinking. lol

You can staple wire across every couple feet and put it up now. Yes this is something you can do yourself. No, your drywallers won't want to do it. They are drywallers.
 
  #8  
Old 06-07-18, 06:38 AM
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Drywallers like to move fast and would definitely not like to add a task they are not used to.

Is there enough space up there to justify an access panel. If so perhaps blown in insulation would be an option. Worth talking to a company and getting a quote.

While it is open you can get those baffles installed near the low vents (soffits).

Is this garage freestanding or attached to house? If attached be sure the wall between house and garage meets code.

Bud
 
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Old 06-07-18, 09:33 AM
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Don't you use a poly vapor retarder in your area? You put up the insulation and cover with poly (stapled) as you go. The poly holds up the insulation.
Yes, but I planned on using faced batts.

You can staple wire across every couple feet and put it up now. Yes this is something you can do yourself.
Sounds simple enough.

Is there enough space up there to justify an access panel. If so perhaps blown in insulation would be an option. Worth talking to a company and getting a quote.
No, there is not. It's a 5:12 roof with 2:12 scissor.

While it is open you can get those baffles installed near the low vents (soffits).
I'll be sure to do that.

Is this garage freestanding or attached to house? If attached be sure the wall between house and garage meets code.
Attached. The wall adjoining the house is already insulated with R-13. I am still uncertain as to whether the sheetrock needs to be 5/8" or if 1/2" is acceptable. I'll have to call the county.
 
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Old 06-07-18, 10:18 AM
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If the Batts are faced the what's the problem? Staple them up!

Drywall on the shared wall of a garage usually has to go all the way to the rafters. The attic spaces can't usually be joined.
 
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Old 06-07-18, 10:34 AM
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I wasn't sure if the staples would hold an R-30 sufficiently without tearing, and I don't like the idea of standing on a ladder stapling insulation over my head 14' feet up over a concrete floor while the insulation flops in my face and tears, falls to the ground. I like the wire idea better. I'll figure it out.

As long as there is not living space above (there isn't), and the ceiling is sheetrocked, then you only have to drywall up to the ceiling.
 
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Old 06-07-18, 10:57 AM
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"As long as there is not living space above (there isn't), and the ceiling is sheetrocked, then you only have to drywall up to the ceiling. "
Adding fire rated drywall to the house attic side above the garage ceiling might reduce the requirement for fire rated at the garage ceiling. Local authority rules.

Consider a lift or two of roll around staging for the insulation install, rent or buy. Staging with a full platform on top makes that work simple.

Bud
 
  #13  
Old 06-07-18, 01:36 PM
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Originally Posted by Bruce H
Have you talked to the drywall folks about doing the insulation & vapor retarder?
I'd offer the drywall guys a case of beer to staple some chicken wire in-between the scissor joists.
Leave the last 2' open to feed the insulation through.

Make sure you have a spool of 30+ lbs fishing line available, cut sections 3x longer than the joist span, make have them place a section of fishing line on top of the chicken wire for each gap t between joists.
Tie the ends together to make a loop. Use the fishing line to pull the bats of insulation up to the joists and then across the chicken wire into place. You can do this from the ground, although you'll probably need a helper with a 10" pole to position the bats.
 
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Old 06-07-18, 04:40 PM
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The insulation could be up already in the time it took everyone to type this. Lol
 
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Old 06-08-18, 07:48 AM
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Tie the ends together to make a loop. Use the fishing line to pull the bats of insulation up to the joists and then across the chicken wire into place.
Attach the fishing line to the batts how?
 
  #16  
Old 06-08-18, 10:11 AM
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Originally Posted by mossman
Attach the fishing line to the batts how?
Duck tape onto the vapor barrier side.

Many years ago I had the "fun" of fixing the rafter insulation in a family owned office buildling.
Property was a former 7-11, converted to regional offices, initially it had a uniform layer of 3" insulation with VB tack stapled to the rafters, but after 30 years of moving partition walls, most of of the VB had been ripped off was flipped back and folde over and laying on top of the drop ceiling.
Had to re-lay all the 3" VB, and then laid unbacked 4" batts going the other direction.

Found that a segmented aluminum pool pole was great at placing batts, also found that fishing line and duck tape was an easy way to hoist the batts up into the attic.
 
  #17  
Old 06-15-18, 06:35 AM
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Is R-38 or even R-30 overkill for an unconditioned garage? If I can go with R-19 for example, it would be cheaper and make my life easier. After all, the goal is to moderate temperature fluctuations, not maintain a constant temperature. Plus, since I have scissor trusses, the thicker insulation will inhibit air flow as I get closer to the eaves. Not sure if that's a big deal since the soffit vents are pretty small anyhow. Garage has a ridge vent as well.
 
 

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