Ground Floor Timber Joists

Wood and similar structural floor materials timber floorboards.

Ground floor timber joists.

Timber floor joists shall be adequate for the spans and loads and be correctly installed. Wood may be sustainably sourced but a lot isn t. Ground floor hollow or timber floor. Solid timber joist sizes are provided in the bs 8103 3 span tables.

The following table gives details of allowable spans and spacing between joists for the most common timber sizes used in floor construction. A round timber with one flat surface and in barns long joists were sometimes supported on a sleeper a timber not joined to but supporting other beams. When choosing a timber structural floor layer and timber joists and bearers as well it s important to consider the source of the timber. Unlike softwood joists timber i joists do not warp over time providing a quiet floor while open metal web joists can provide an easy means of installing services beam and block ground floors the most popular option.

The ends of these timber joists are built into or suspended by joist hangers from the external walls of the property. Joists left out of an area form an opening called a well as in a stairwell or chimney well. Joists on the ground floor were sometimes a pole pole joist half round joist log joist. Creating a vapor barrier only delays the effects of moisture on the wood of the floor.

The span table for a 30 psf live load 10psf dead load floor indicates a required fb value of 1 315 and a minimum e value of 1 800 000. Where the tables do not apply or where there are concentrated loads floor joists should be designed by an engineer in accordance with technical requirement r5. True floor joist span calculations can only be made by a structural engineer or contractor. Hollow floors also known as suspended or timber floors are simply timber joists suspended across and supported by load bearing walls under the floor.

In the example the joists have a spacing of 16 inches and a span of 11 feet 2 inches. Building a wooden floor on top of a dirt floor will lead to eventual rotting of even treated wood though the barrier will delay the onset of this for several years depending on the environmental conditions of the building region.