Floor Joist In Attic

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.

Floor joist in attic.

In buildings with basements the first level of floor joists serves the same purpose. An inaccessible attic space on the other hand might have a live load of only 20 psf. But you can still double the capacity of the existing 2x6s in the attic floor so first let s make sure that s enough for your situation. In the past 2x4s or 2x6s were sometimes used as floor joists.

How to reinforce an attic floor with sister joists. 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. First you ll need to measure the area you want to floor so you can calculate how much wood you ll require. True floor joist span calculations can only be made by a structural engineer or contractor.

Clear the joist spaces. Read to learn more. But before even they can start on a job that involves altering your home s structure they ll almost certainly have to pull a. My calculations tell me assuming 2 southern yellow pine joists which are common in my area that 2x6s 16 inches on center will span 9 feet 9 inches with allowable deflection being the governing factor.

This size is no longer acceptable when framing a structure. You need 3 4 inch plywood. Modifying an attic floor s joist system is a job for the pros. Attic dek is a specially designed attic floor system that consists of 16 or 24 squares attached to the top of ceiling joists.

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. How to build attic flooring on joists. Also remove any blocking or bridging between the joists as applicable. Floor joists installed on second or third or higher levels double as ceiling joists for the level below.

Most people store clothes antiques junk photo albums and many of their long forgotten things in this rather dingy area often known as the dead load. This sample table gives minimum floor joist sizes for joists spaced at 16 inches and 24 inches on center o c for 2 grade lumber with 10. To floor an attic you ll need to install a sub floor for support before laying your plywood floor. You ll have to construct a wooden frame or sub floor with boards 16 inches apart to provide extra support for the floor.

Joist span tables.