Timber Joists On Concrete Floor

Common sense tells you that large floor joists can carry more load and spacing joists closer together also increases the load bearing capacity of a floor.

Timber joists on concrete floor. But larger is not always better when builders are constructing a home or adding a room addition. The procedure for installing a floor structure over a slab with 2 by 6 joists can be. Install it flat on the slab surface with the outside edge aligned against the side wall or the edge of the floor line. The new timber joists need to be suspended above the concrete normally by around 150mm to prevent moisture transmission through the timber and to provide airflow around the floor.

Secure each length to the slab with concrete nails spaced approximately 80 cm 32 inches apart and 20 to 30 cm 8 to 12 inches from each end. These will be the end sill plates that support the ends of the floor joists. Concrete can also easily accommodate setdowns and folds in the floor as might occur for bathroom wet areas or split level floors. The main problem is deflection bounce and thermal movement expansion and contraction most flexible adhesives on their do not allow for the type of movement found in a timber floor especially over a large area.

Building a framed wood floor over an existing concrete slab can provide the space needed for electric wiring heat venting plumbing drain lines and added insulation when remodeling a basement or garage space. The extra two inches of vertical distance when a floor is framed with 2 x 10 joists rather than 2 x 12s can be quite important for example.