Attic Insulation In 2x4 Ceiling Joist Space

How to reinforce an attic floor with sister joists.

Attic insulation in 2x4 ceiling joist space.

Standard joist spacing for the installation of attic flooring materials is 16 inches on center oc meaning the distance from the center of one joist to the center of the next joist is 16 inches. Option 2 has the benefit of preventing any thermal bridging via the ceiling joists. Now that you understand insulation r values you can make sure your home is properly insulated. If you want to put down flooring in your attic and want more insulation underneath that floor then you need to increase your joist size.

Put insulation meant for 2x4 framed walls between the joists which will be the same height as the joists then lay a perpendicular layer of attic insulation maybe r 30 on top of them. Ceiling joists are the horizontal boards that span the width of the house resting on the outer wall plates and possibly on. When using fiberglass insulation the pink stuff the attic roof rafter will need to be at least 16 deep. They are directly below the roof sheathing and are were insulated with fiberglass batts stapled between the 2x4 rafters.

Clear the joist spaces. Over the past several years there has been an increased focus on making insulation codes more stringent. Also remove any blocking or bridging between the joists as applicable. Always cover the tops of the ceiling joists to make sure the insulation is deep enough to reach your target r value and to prevent thermal bridging the heat loss that occurs through the wood framing.

Pull out all insulation and any debris from all of the joist spaces so you can see the full length of each joist including where it meets the exterior walls. Current insulation code requires r 49 insulation in the ceiling. Work from the perimeter of the attic toward the door or hatch so that you don t trample all over the insulation you just put in. If you don t have all the tools you need to install insulation and improve your insulation r ratings yourself consider our tool rental services.

I have a 1925 bungalow in michigan climate zone 5. There are some unfinished crawl space areas in the corners on the upper floor.