How To Strengthen Attic Floor Joists

1 grade 2 by 6 douglas fir larch joists spaced 16 inches on center.

How to strengthen attic floor joists.

April 7 2017 by zamira leave a comment. If your attic joists won t bear the weight necessary to finish out a living space but the engineer cleared them to support floor decking for light storage you can install inch plywood or. As an example consider a room with a floor area of 10 feet by 11 feet 2 inches built with no. Gluing and screwing a 3 4 attic subfloor and providing solid bridging should also be considered.

A design value table shows that the joists have an fb value of 1 495 and an e value of 1 900 000. Strengthening attic joists for live loads by sistering if the attic joists are not adequate one way to strengthen the floor for live loads is to sister the old joists. This solution doesn t make the floor as stiff as the other solutions but since it s relatively easy and inexpensive you might want to try it first. Use a design value table to find the fb value for your floor 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. Use a span table to determine the necessary joist dimensions given their span length spacing wood species and grade. Strengthening attic floor joists. Sistering is the process of adding a new joist next to each existing joist.

Even if your joists already have a row of bridging at the center of the span adding a row on each side of the existing bridging will stiffen the floor. 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. Joints in built up wood floor joists floor joists before finishing an attic up attic joists for living e strengthening upstairs floors strutting. In massachusetts attic floors must support at least 30 lbs ft live load the same as bedroom floors if the attic is accessed by means of a fixed stairway 780 cmr 5502 3 1.