Attic Insulation In 2x4 Ceiling Joist Space

When using fiberglass insulation the pink stuff the attic roof rafter will need to be at least 16 deep.

Attic insulation in 2x4 ceiling joist space.

How to reinforce an attic floor with sister joists. How to increase the interior ceiling joist for r38 insulation. 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. 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.

Current insulation code requires r 49 insulation in the ceiling. Now that you understand insulation r values you can make sure your home is properly insulated. Enjoy better floor to floor climate control in your home by installing ceiling insulation. 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.

I have a 1925 bungalow in michigan climate zone 5. 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. Ceiling joists are the horizontal boards that span the width of the house resting on the outer wall plates and possibly on. They are directly below the roof sheathing and are were insulated with fiberglass batts stapled between the 2x4 rafters.

Also remove any blocking or bridging between the joists as applicable. Sistering 2x6 joists next to your current 2x4 joists will simply give you a new floor height of 5 1 2 inches as opposed to the current 3 1 2 inches. 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. 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.

Option 2 has the benefit of preventing any thermal bridging via the ceiling joists. Over the past several years there has been an increased focus on making insulation codes more stringent.