Floor Joist In Attic

You ll have to construct a wooden frame or sub floor with boards 16 inches apart to provide extra support for the floor.

Floor joist in attic.

True floor joist span calculations can only be made by a structural engineer or contractor. Joist span tables. In buildings with basements the first level of floor joists serves the same purpose. How to reinforce an attic floor with sister joists.

But before even they can start on a job that involves altering your home s structure they ll almost certainly have to pull a. Attic dek is a specially designed attic floor system that consists of 16 or 24 squares attached to the top of ceiling joists. 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 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.

The attic is one of the most unused and under designed spaces of a home. You need 3 4 inch plywood. This size is no longer acceptable when framing a structure. Joist spacing and attic use the joist spacing in some attics is 24 inches and 1 2 inch sheets will sag and possibly break when spanning that distance.

In the past 2x4s or 2x6s were sometimes used as floor joists. Floor joists installed on second or third or higher levels double as ceiling joists for the level below. An inaccessible attic space on the other hand might have a live load of only 20 psf. Clear the joist spaces.

First you ll need to measure the area you want to floor so you can calculate how much wood you ll require. Also remove any blocking or bridging between the joists as applicable. 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. 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.

Read to learn more. How to build attic flooring on joists. To floor an attic you ll need to install a sub floor for support before laying your plywood floor. 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.

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.