insulating garage attic

[picksbigwagon]

Yep, I am getting ready to start this project, the last time I posted was very helpful, now I have some new questions. First of all the background information: new construction, there is a vapor barrier ( photographic evidence while the house was being built) already have lights up there (builder did it on their own )....I will be cutting a hole in the ceiling of the garage for a drop down attic ladder. Now come the questions:

1. ceiling to floor measurement in 10'5" verticaly, how long of a ladder do I purchase?

2. WHen insulating, how far do I put the insulation i.e edge to edge, leave space for the soffit breathing?

3. the joists are 2 feet apart, and the trusses were built to support flooring and storage in the attic (2x6's) will 1/2" OSB be strong enough? I have a ton of room so I won't be stacking it all in the same spot.

Thanks for the help, Someday I will get the honey do list done....and monkeys will fly out of my

[soldoncass]

1. Drop-down ladders are rated for a range of ceiling heights, so just get one that has 10' 6" in it's range....make sure it is 22 inches wide, so it fits between the trusses. There are some wider, that have to be framed for (when built). If the garage is attached to the house, make sure to maintain the firewall integrity in the garage sheetrock.

2.The fiberglass rolls should cover the wall plates and be tight together all the way across ceiling, as well as the other wall plate. If you use R-19 (6") 22" wide batts, you won't need propervents stapled up the roof plywood....IF THEY USED ENERGY TRUSSES. If they used regular garage trusses,or you are using thicker insulation than R-19, you will need proper vents to keep the air moving from soffit areas.

3.I would go 5/8 or 3/4 inch cdx plywood on the floor....lighter than osb, and won't be spongy under your feet.

[cavalierowner]

Soldencass eluded to it and it's an important point. If the sheetrock on the garage ceiling is a part of the fire rating between the garage and the house, you probably cannot use just any old attic access stair. It will have to be fire rated. There are manufacturers out there that make fire rated stairs; I've never priced them, but I have an uneasy feeling they're not going to be cheap.

Is the garage attic open to the house attic? If so, you will probably need a rated stair. I would suggest talking to the building inspector to find out if one is required.

[picksbigwagon]

the garage is attached to a corner of the house and it does not share access to the attic of the house. I think I will probably get a fire rated ladder, I have priced them and yes they are not cheap.

what are energy trusses? I haven't cracked teh ceiling yet, but when I do I will take pictures and post them here. It won't be until september though.....Gotta get through the summer heat

[soldoncass]

The difference between regular and energy trusses is simply the "height above plate" distance.....ie: they are made higher, so you can get more insulation on the plateline. On a verticle line ,on the outside of the plate, reg. trusses measure 4 inches, while energy trusses are 7 inches. With your 2x6 bottom chord, my guess is they are energy style......only a guess.