going to insulate my attic, it has2x4 joists. Should i lay 4'' batts in the joists, and put 6-8" crosswise.?

Answer 1

I would put R13 batts in between the ceiling joists, with the vapor barrier facing down. This is especially important in cold climates where you may have freezing temperatures. However, I would not put additional insulation crosswise, as that would conceal the ceiling joists and make it virtually impossible to walk or crawl in your attic space. You may not have to go up there very often, but when you do, you'll need somewhere to step.

If you want additional insulation, consider installing unfaced insulation between your rafters. You could use fiberglass or polystyrene sheets cut to size. Hold it in place with wires run perpendicular to the rafters.

I would not use cellulose fibers blown into the attic. I had that done in my house many years ago, and ever since I've had a dust problem. I don't know how the dust could be getting through the ceiling, and perhaps the insulation is not to blame. I just wouldn't use cellulose again.

Answer 2

You need to check out the size of the floor joists. Make sure the contractor didn't skimp on the attic joists. Preferably for this much weight, 2x10's would be the best. You can use 2x8's, but definitely NOT 2x6's. If they're 2x6's you'll need to reinforce these with either wider joists or T's which a contractor can help you with. Also how old is this house? The last thing you want is for your ceiling to collapse & ruin your entire home. ~m~

Answer 3

Your plan should work just fine. you may want to pay secial attention around things like leaks where air pipes extend thru the ceiling etc. You could use spray foam around those areas. Also, put weather-stripping on the attic access doors. You can plug open joist spaces under side walls by rolling the fiberglass batt to fit, place it in a plastic garbage bag. Fold the top of the bag over and stuff the bag into the joist cavity. The plastic bag stops the airflow and the insulatiion makes the bag expand tightly to close off gaps.

Good luck

Answer 4

remember that you need to leave a vapor barrier inbetween the insulation and the wood so that you dont get a condensation build up and wood rot.

Answer 5

why not do it the proper way...call someone in to "blow" in the insulation...then you will get the best coverage..don't forget to make sure the air movement is still there....that's what eaves are for..make sure that outside air can get in through the eaves...and out the top of the roof...
otherwise....trouble @!!!!!

Answer 6

You could try having paper fiber blown in.

Answer 7

This is an excellent approach.