Size Of Timber Floor Joists

A floor s framework is made up mostly of wooden joists that run parallel to one another at regular intervals.

Size of timber floor joists.

Find the column for your dead load and spacing and the row for your timber size to find the permissible clear span in metres. Click on a span to generate a full calculation you can adjust the exact span. Floor joists or beams provide the below surface support for the wood subfloor of a room. Floor joists capacities carrying capacities of domestic timber floor joists grade c in metric units floors live loads floors and minimum uniformly distributed live loads maximum size of duct or pipe through steel joists k series joists and maximum size of ducts and pipes.

All the figures are based on normal domestic floor loadings where the floor construction is typically 18 25mm floor boards sheets with up to 12 5mm thick plasterboard and skim underneath. Even when a contractor knows which kind of joists would be best for a specific project he can t just go about placing an order with nothing but floor joist spans to guide him. The following table gives details of allowable spans and spacing between joists for the most common timber sizes used in floor construction. If the joist spacing will be 16 inches 406 4 mm a joist size of 2 x 8 should be used even if the length is only 8 feet 2 44 m.

Some newer homes have manufactured i beam shaped joists. These tables can help calculate whether floor joists are strong enough to support themselves and the load they carry without the help of any walls underneath. This span table is to the format and methodology given in bs 5268 7 1. Surveyors and structural engineers use data from tables below to help calculate the size of timbers necessary to give adequate support to timber floors.

When building a house or even a deck it is important to confirm you have the correct joist sizes spans and spacing before you get started. Floor joists are typically 2 by 8s 2 by 10s or 2 by 12s. A structure with a 10 foot 3 05 m length and joists set 12 inches 304 8 mm apart would require using a floor joist size of 2 x 8 50 8 x 203 mm. While most residential construction uses 2x8 joists with 16 inch spacing there are many other factors you need to consider when determining the proper joist span length.

These spans were calculated using our floor joist calculation engine. Ceiling joists are usually 2 by 6s or sometimes 2 by 4s if it is an older home. Though joists may be any size that you desire using typical floor joist and beam specifications ensures that you can find hardware to fit the joists and that the floor provides adequate support for furniture and other items in a room.