As with the joist size the building code for your structure will stipulate the proper spacing between floor joists.
Standard floor joist spacing uk.
In many home constructions joists sit 16 inches apart beneath the floor.
Two options that arise could be your wider 24 and your narrower 12 options for spacing.
In many circumstances 16 inches would be your standard spacing for shed floor joist but this is just a rough guideline.
If a floor needs to support more than common items you may choose to reinforce the floor by spacing joists closer together.
This means from the center of one upright joist to the center of the next.
Builders can adjust their choice of lumber size and spacing depending on circumstances.
For upper floors with a 22mm thick chipboard decking and 12 5mm plasterboard ceiling a dead load of between 0 25kn m 2 and 0 5kn m 2 may be assumed.
Joists are to have minimum end bearing of 40mm.
Floor joist span tables for surveyors floor construction surveyors and structural engineers use data from tables below to help calculate the size of timbers necessary to give adequate support to timber floors.
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.
The floor joist spacing is the distance between the centers of any two installed joists.
The floor joist span tables are based on the loadings given in the amended version of bs 6399 1 which is an imposed load of either a uniformly distributed load of 1 5 kn m or a concentrated load of 1 4 kn.
You should check with your local building department for construction requirements in your area.
Looking at this table you will see there is a choice in the size of floor joist 2 x 6 2 x 8 2 x 10 or 2 x 12 and there is a choice in the joist spacing 12 16 or 14.
The section sizes of the floor joists given in tables 1 and 2 should be regularised or be als or cls to enable floors and ceilings to be level.
Normally floor joists are spaced 16 inches apart on center.
The code itself is determined by the engineering requirements of a particular building.
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.
