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.
Add bridging attic joist.
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.
Yet it is not uncommon to find bridging not properly installed or missing all together.
Attic hatch or door.
Cut and install lumber blocking or bridging between the joists if required by local code.
Measure the width and length of the existing joist.
Pull down stair or ladder.
Divide the span by three and add rows of bridging at both of the one third points.
Affix rigid foam insulation to the attic side of the hatch or door.
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.
Installing flooring material over the attic doesn t quite leave room for the recommended insulation space needed to provide efficient home energy.
If the existing joist system is very close to being sufficient to support a new attic flooring the addition of bridging between the joists may be all that s required.
Add nails or screws if necessary.
Each piece of bridging requires four nails two at each end.
Start by making sure the original bridging is tightly fastened.
Bridging or x bracing allows joists to share weight.
Put 2x8 blocks at the third points set at the midheight of the assembly and bridging the horizontal joint between top and bottom joists.
Then measure the span of the joists the distance between walls or beams that support the joists.
Once the structure has passed the building inspection you can run electrical plumbing and mechanical lines and insulation as applicable then install plywood subflooring.
Most new construction uses 2 by 8 lumber for joists although 2 by 6.
Toenail the blocks or end nail through the joists to tie everything together.
Purchase the type of lumber that matches the width of the existing joist.
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.
Add weatherstripping around the perimeter and a sweep to the door of a walk up attic.