Insulation

[Ian]

Sooo, I'm gonna type some stuff up and back this thread up with some pictures in the morning.

I have a 2 bay garage with 2 bedrooms and 1.5 baths over it. The space is cold all winter long because it's basically surrounded on 5 sides by cold air.

The full bath has been down to the studs since we bought the house almost 2 years ago and this winter I started sweating in new shower plumbing, insulating, and other core prep for finishing it this spring. The plumber hacked up the primary joist below where the tub used to be and when I was doing some work on the new shower valve, I noticed the floor was pretty noisy. After some additional assessment I could tell the joist was sagging pretty badly and compromising the structural integrity of what is going to be a tiled shower floor.

Fast forward to this weekend, I dropped a portion of the ceiling in the garage to sister a new joist and support the floor. One thing led to another and I found the 8/3 wire the mouse chewed through in 4 different spots and dropped the rest of the ceiling in that garage bay to make sure the wire was good back to the panel. During the process, I found that close to 70% of the insulation had been compromised by mice, meaning a bunch of trips to bulky waste today getting rid of Sheetrock and insulation.

Now I have one bay of the garage completely exposed and and trying to make an intelligent decision on how to re-insulate before putting up new fire rated sheet rock.

Option 1: R38 batts with the vapor barrier facing the conditioned space which essentially replaces what was there with non mouse superhighway stuff.

Option 2: DIY spray foam kit to seal the underside where the floor from above sits on top of the joists, then the appropriate sized (thinking it will be R30 depth) fiberglass batts under that with the sheet rock keeping everything sealed up.

Option 3: Hire someone for $$$ to come in and do it their way.

My questions:

While I have one bay exposed, should I bite the bullet and tear down the other side? I'm assuming the mice made it to that side too.

Should I consider trying to drop the ceiling height by an inch or so using sheets of foam board for some extra R value?

Am I insane?

Is there something else I should remember to do while I have this area exposed down to just the joists? (I'm going to re-route some coax and cat6e cables already)

[Nebe]

Tear the rest down. Run some wires so you can mount some track lighting in your garage. That was the best thing I ever did to my old house, as you can aim the tracks for different projects you may have in the garage. Hire one of those insulation companies that can spray foam. It's amazing how well the closed cell foam insulates.
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[Raven]

@ Nebe?
i have a barn section that needs insulation bad
it's like a walk in freezer set at 20 degrees
so, if i have a company foam it
are the truss's coated too so i can cover up
the foam with say plywood and not see it?

[Liv2Fish]

My $.02.

1. You can typically pay someone for less than you can buy the batts. Before they or you install batts, use canned foam to seal any wire holes or pipes, etc. I prefer un-faced batts with polly vapor barrier but since you only have one bay stripped, it really doesn't matter.

2. If it were me, I'd strip the entire garage ceiling and warm walls, add wiring for what ever I could think of for future and have it sprayed with closed cell foam. They will spray to what ever depth you want. If you fill to the depth of the joist, you'll get something like R50. Walls you can get up to almost R30. It's usually 2.5 - 3 x the $ of doing batts.

[nightfighter]

Drove past Glastonbury around 7pm last night on my return leg from Philadelphia....

It is a budgetary issue. Batt insulation is not going to improve the cold you have been experiencing, unless you can install radiant heat from the underside of the floors. Foam would be first choice. Again, price dependent. Run all wiring and plumbing first. Add some PVC tube messengers for future use. Planning accessible shutoffs is key. And if you have to add wiring in the future that you had not planned for, it is a garage ceiling, so adding race tracks on the sheetrock will not be out of the question.

[nightfighter]

Originally Posted by Raven

@ Nebe?
i have a barn section that needs insulation bad
it's like a walk in freezer set at 20 degrees
so, if i have a company foam it
are the truss's coated too so i can cover up
the foam with say plywood and not see it?

Foam fills the rafter bays, not the trusses. Google foam insulation and look at images.

[trevier]

foam it, it's the best hands down,expensive but the best.

[buckman]

Closed cell is about R7 per inch . They usually don't fill it solid . Open cell they fill solid and trim flush .
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[Ian]

Made a step towards being ready to accept foam as my solution of choice today. Entire house has Type L copper but acidic well water. Had the first pin hole leak a week or two ago so I decided that if I'm going to spray, I'm replacing the plumbing that runs in the garage ceiling. Ran PEX from the main line to the shared wall for both bathrooms and up through the floor into the exiting copper plumbing (it's a crazy collection of intertwined pipes that haven't leaked yet so I'll deal with these when I have to)

PEX is so damn cheap but according to my research the only fittings that don't restrict the ID of the pipes are the push-fits which are more $ than gold.

Couple hundred $ later and my potentially risky copper and freeze prone plumbing are no-more (although all my waste and vent pipes are still copper.)

I'm going to see if I can get someone to quote ~$3k for the job with closed cell and if I can hit that target, I'm thinking I'll pull the trigger.

Rest of the ceiling is coming down this week.
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