Add Bridging Attic Joist

Cut and install lumber blocking or bridging between the joists if required by local code.

Add bridging attic joist.

Attach the bridging fasten metal bridging with 1 3 8 in. Each piece of bridging requires four nails two at each end. Toenail the blocks or end nail through the joists to tie everything together. Then measure the span of the joists the distance between walls or beams that support the joists.

Add nails or screws if necessary. Pull down stair or ladder. You could even possibly introduce a good crown to each by holding the bottom chord in place with a slightly long 2 4 post under the center as you install it. Divide the span by three and add rows of bridging at both of the one third points.

Put 2x8 blocks at the third points set at the midheight of the assembly and bridging the horizontal joint between top and bottom joists. Purchase the type of lumber that matches the width of the existing joist. Most new construction uses 2 by 8 lumber for joists although 2 by 6. What i would do is to add a 2 4 to the top and bottom of each joist using glue and structural screws to convert each joist into an i joist in place piffin writes.

A raised platform of lumber in dimensions of 2 4 or 2 6 with insulation placed between joists and covered up with a 12 inch plywood helps build the right flooring. Use a zippered insulated tent to keep the enclosure draft free attic tent at 7 attic cover insulator 120. Start by making sure the original bridging is tightly fastened. Attic hatch or door.

Once the structure has passed the building inspection you can run electrical plumbing and mechanical lines and insulation as applicable then install plywood subflooring. Add weatherstripping around the perimeter and a sweep to the door of a walk up attic. Bridging or x bracing allows joists to share weight. Yet it is not uncommon to find bridging not properly installed or missing all together.

Proper bridging distributes the load on the floor to other joists and over time prevents floors from sagging and squeaking do to floor joists twisting and warping. Measure the width and length of the existing joist. Floor joist bridging is critical to the structural strength of a floor as shown in figure 1.