Subfloor Then Spacers Over Joists Under Flooring

On wood frame floors the subflooring provides a continuous structural surface over the floor joists.

Subfloor then spacers over joists under flooring.

This method of laying a sturdy subfloor on top of joists and then topping the subfloor with a cosmetic only flooring top creates a tighter stronger structure. Avoid using green joists for your floors but instead use sturdy performance tested lumber. There was never any insulation installed under the floor. The vapor barrier is just beneath the subfloor but on top of the joists.

A 3 4 inch plywood subfloor on a joist structure with 24 inch spacing needs the extra thickness of cementboard or the floor will flex and the tiles will crack. Wet lumber may lead to dimensional changes as the joists dry resulting in nail pops and floor squeaks. Use trus joist tji joists or kiln dried performance tested lumber such as weyerhaeuser framer series lumber which is more dimensionally stable than green lumber. In addition be sure to allow the subfloor dry completely before installing any additional top flooring.

Always store floor panels under cover. Some experts recommend choosing kiln dried lumber for floor joists. With the above specs the flooring should be installed perpendicular to the floor joists. The finished floor is then installed on top of the subfloor.

In basements and in homes with slab on grade foundations the subfloor may simply be a concrete slab. Uncoupling membranes aren t recommended for tiles smaller than 2 inches square and should not be used when covering old hardwood flooring due to adhesion problems. The subfloor is the foundation beneath finish flooring materials. Inspect the subfloor from below and note the direction of the joists.

This permits the floor to flex and expand a little as necessary. The subfloor is the decking installed on top of flooring joists. I m putting down a laminate floor over a 3 4 plywood subfloor that is over a unconditioned crawlspace in north florida. The manufacturer of the flooring suggests a 6 mil plastic underlayment for the flooring to block moisture but my concern is the potential for damage to the plywood by locking any moisture in.

It is flexible it can be changed out it is inexpensive. The thickness of plywood panels in a subfloor is regulated by the. Would 15 tar paper be a viable alternative to use. The crawl space has a scratch coat of cement on the floor.