Loft Floor Joist Calculator

In the example the joists have a spacing of 16 inches and a span of 11 feet 2 inches.

Loft floor joist calculator.

Calculations to bs 5268 2 2002. In this case your joists are adequate to support a 30 psf live load and 10 psf dead load. These small areas are usually door opening on the interior and people are trained that these areas are the strongest. Floor joist span calculator.

Select the on center spacing for the joists. 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. When you re carrying out your planned loft conversion it s highly likely you ll find that the existing ceiling joists or gang nailed roof truss chords in your property are not designed to carry a full domestic floor load. Most lay outs are on 16 so the field is pre selected.

This is how far apart they will be. The full version allows any size. This is the distance between joist centres. This demo version is fixed at 1m clear span.

Next use the buttons in the table to select the maximum length in feet or metres in brackets that your floor joists must span. It has been my experience to never use a beam smaller than a two ply 2 x 8. Span calculator for wood joists and rafters also available for the android os. Usually 400 450 or 600mm but any value can be used up to 610mm max.

To use the joist span calculator below first select the species of lumber you will use for your construction project from the drop down list. The highest is a fully loaded floor 70 pounds per square foot. 1 enter joist details 1 1 span and joist spacing. The new floor joists of your loft conversion will need to offer at least 30 minutes worth of fire protection which could mean replastering the ceilings in those first floor rooms below.

Domestic floor joist calculator. 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. There are six choices. The loft room will also have to be separated by a fire door either at the top or bottom of the new stairs.

This calculator matches up with 90 of the applications in the 2012 international residential code book. Also available for the android os. The lowest is a plain ceiling joist with no storage 10 pounds per square foot.