Timber Floor Joist Sizes

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.

Timber floor joist sizes. 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. See the image below for an example of joists spaced 16 on center 16 o c. Since the example house we are designing for is 12 feet wide we need to find in the floor joist span table a joist size and centering that can span 12 or wider.

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. This sample table gives minimum floor joist sizes for joists spaced at 16 inches and 24 inches on center o c for 2 grade lumber with 10 pounds per square foot of dead load and 40 pounds of live load which is typical of normal residential construction. Joist span and spacing is set by your local building code. Find the column for your dead load and spacing and the row for your timber size to find the permissible clear span in metres.

Surveyors and structural engineers use data from tables below to help calculate the size of timbers necessary to give adequate support to timber floors. The floor joist spacing is the distance between the centers of any two installed joists. Floor joists or beams provide the below surface support for the wood subfloor of a room.