Insulation Question

[Ferrino]

I have one last area of my garage framing that is open and not drywalled - the slanted rafters shown at the top of this photo:

See Pic Here

I would like to drywall this area and was thinking that, while I'm at it, I would add some insulation to help reduce the heat in the Summer (sun shines directly on that roof). I have never insulated before and was wondering which product you would recommend please and how it is attached/installed? Am I supposed to use those baffles so that there is an air-pocket between the roof and the insulation?

As far as I can see, this rafter space does not get ventilation from outside - there are no soffit vents on the outside of the garage.

The house was built in 1980 and I assume there was no good reason not to drywall this roof, other than to save costs?

Many thanks!

 

[holland_patrick]

http://www.sprayfoamdirect.com/products/spray-foam-kits

 

[Ferrino]

Thanks for the suggestion! I'd rather not use a sprayed-on material though. Could I not just buy some sort of roll of insulation?

 

[dshop]

Last summer I had a local insulation company spray foam my entire shop, walls and ceiling, all the way, no gaps, and the comfort level and energy savings are incredible. Open cell foam highly recommended as an insulation product...I don't think you will ever regret having the proper insulation in your building. Go cheap on insulation and you will pay for the increased energy costs for years to come.

my experience, yours may differ. I am in the Raleigh, NC area, temps can range from 10* in winter to 105* in the worst of summer.

 

[Ferrino]

Any other product suggestions, please?

 

[dshop]

ferrino,
you asked for sugggestions and you got them. If you think a few sheets of newspaper or a piece of aluminum foil is the way to go, then go for it and stop wasting forum members advise on tested solutions.

 

[crepr12]

1,2,3,4 post and you give this guy tude....WOW...good luck OP

 

[cruzzer]

The baffles would need to vent top and bottom and then you would put fiberglass batting over it. You'll be lucky to get r14 out of it that way. Any reason your against the spray foam? Is it cost or the DIY factor. I spayed my basement walls myself and my neighbor did his attic with a DIY kit that seamed ok. Tiger foam? My kit was soythane in the fast kick gun and I would not want to spray this overhead as the spay gun is heavy after 15-20 minutes. The spray foam can go right on the wood. If you put a way to fill try the loose cellulose insulation. If its packed sense enough it makes for good insulation. Myself I'd do a skim coat of foam, like 1-2" to get a good vapor barrier then fill with the cellulose. Do a search on super insulated homes. Lots of good ideas.

 

[Ferrino]

Hi and thanks for your reply. I guess I am unclear on the ventilation requirements for either fiberglass batting or spray foam. There is currently no ventilation to the space between the rafters that I would be sealing up with drywall (i.e. no vents at top and no soffits where the rafters meet the outside eaves above the garage door). Are you saying that with whichever insulation I use, I would need to introduce soffit vents at either end? I've looked around other areas of the house and don't see soffit vents on any eaves - is this climate-specific? I am in SoCal if that makes a difference. I mentioned it to a few locals and they were under the impression it's not unusual to have no soffit venting around here.

My only aversion to spray foam is my ability to apply it and all the equipment I imagine that it requires. I just imagined rolls of fiberglass would take less time and effort.

Thanks!

The baffles would need to vent top and bottom and then you would put fiberglass batting over it. You'll be lucky to get r14 out of it that way. Any reason your against the spray foam? Is it cost or the DIY factor. I spayed my basement walls myself and my neighbor did his attic with a DIY kit that seamed ok. Tiger foam? My kit was soythane in the fast kick gun and I would not want to spray this overhead as the spay gun is heavy after 15-20 minutes. The spray foam can go right on the wood. If you put a way to fill try the loose cellulose insulation. If its packed sense enough it makes for good insulation. Myself I'd do a skim coat of foam, like 1-2" to get a good vapor barrier then fill with the cellulose. Do a search on super insulated homes. Lots of good ideas.