Reinforcing 2x4 Attic Joists

My ultimate plan is to sister the joists to make a sturdier attic ceiling blow in insulation on the roof and put plywood across the joists for a storage platform for my boxes christmas decorations etc.

Reinforcing 2x4 attic joists.

Decided to use 2x4 at 16 inch centers as joists. The type of modifications selected for reinforcing the joists will depend on the recommendations of the engineer but the following methods are commonly used to beef up undersized attic joists. Beefing up attic joists for living space. Senna posted in construction techniques on may 26 2004 09 05am just installed an attic ladder in 90 year old house.

With the 2x4 joists 16 inch centers running the 15 foot width. The existing ceiling joists are 2x6s clear spanning about 11 feet 3 inches. If the attic joists are not adequate one way to strengthen the floor for live loads is to sister the old joists. Place the board vertically with the ends overlapping the ceiling rafter and the joist.

There is a 1 2 plywood sub floor on top of the joists. Each joist is strong enough to support my weight 175lbs concentrated in a 1 segment of the joist and. As you can imagine the floor bends a bit when walked on there are tongue and groove planks over the joists in the attic for a floor. Plan is to use attic for storage not for living.

Each joist is connected by a vertical 2x4 to the roof rafter above it positioned about 4 from the wall. I want to finish this space with drywall walls and ceiling and also a drywall ceiling in the garage under the joists. 2x10s are the code today. 2x4 s actual size spaced 16 on center running the width of the building uninterrupted with the ends resting on top of the wall top plate.

In the case of 2x6 joists you can pair them up with additional 2x6 joists by nailing them together side by side. Nail the board to the joist and rafter with two nails at each spot. I d like to double my ceiling joists to make my attic space easier to work in for electrical plumbing and for lightweight storage. Our house has almost exactly the same thing.

I talked to a structural engineer and he advised to sister the existing 2 4 joists. Cut a 2 by 4 inch board to match the distance you measured. Sistering is the process of adding a new joist next to each existing joist. 20 and are 16 on center.

The attic joists are only 2x4s and are 27 inch on center i double checked. I have places in the attic where there is a 12 foot span only supported by 2x4s.