Replies

1. 
   David_Thomas | Dec 01, 2001 04:38am | #1

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   While the garage below will be unheated it won't be as cold as the outside air and will not have wind or weather exposure. At a minimium, I'd put in FG batting and a poly vapor barrier, being careful to minimize damage to and penetration through the vapor barrier. A better approach would be to spray an inch or two of urethane foam onto the subflooring from underneath - that creates a very good vapor barrier that is not subject to sheetrock screws, light fixture, etc. Then fill the rest of the of bay with FG batting or cellulose.

   Note that (if you are building to code), you need a 2-hour fire wall between a garage and living space. That can be done with two layers of 5/8" sheetrock, or single 5/8 on resilent channel, or single 5/8 plus 1.25(?) inches of wood (thicker subfloor or subfloor plus hardwood flooring. Check locally which are allowed. Any stairways between the floors also need 2-hour firewall and a self-closing door. Talk to your inspector early on about his/her particular concerns. Some don't want plastic pipe to go between garage and living space, for instance, so you can use metal or have covers on them that auotmatically close when the plastic melts. -David

1. 
   Bob_Walker | Dec 01, 2001 02:14pm | #2

   *Also, don't forget to protect against carbon monoxide infiltration. Also, don't worry about the noise and vibration of the garage door openers, you'll get used to it after a couple of years. Of course, if you usually leave before your SO arises, she won't!

1. 
   Mike_Smith | Dec 01, 2001 06:14pm | #3

   *made a mess of that.. here's what i meant to say...dave.. those fire code restrictions may be specific to your locus.. here's CABO 1 & 2 Family : 309.2: Separation Required. The garage shall be separated from the residence and it's attic area by means of minimum 1/2" (12.7mm) gypsum board applied to the garage side. note that it no longer requires 5/8 firecode either.. .. i don't know what the new Universal Code will say... but it may never be adopted either... in any case.. check with your local authorities and watch the penetrations for the CO infiltration as Bob says as for insulation.. we drill holes thru the band joist and blow the floor joist bays solid with cellulose...if you want more .. we add foam below the ceiling and furr the ceiling...in our last bedroom over garage job, with 2x10 joists and 1" foam we figured an R-value of 37..

1. 
   David_Thomas | Dec 03, 2001 06:28am | #4

   *Mike: Yes, those are my local requirements. Come to think of it, they could be a lot more strict here due to the high number of rapidly moving house fires we have up here. (Wood stoves, weird heaters, VERY dry wood and furnishings, hgiher % of smokers, etc). -David

2. 
   Dan_Sweeney | Dec 03, 2001 06:28am | #5

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   My new home will have the Master Bedroom over the garage. What do you recommend to insulate the room, since it will be over an unheated space?