Rafter Sizes For A Pitched Roof Uk

Usually 400 450 or 600mm but any value can be used up to 610mm max.

Rafter sizes for a pitched roof uk.

Roof pitch between 15 and 22 5 degrees with rafter spacing strength. Surveyors span tables for designing roof rafters. You can assess this in two ways either as the roof pitch angles which the rafters make with the horizontal or the proportion between the run and the rise of the roof. 4 8 2 2 4 for one half of your roof s width b skip this step if you already know what measurement half the width of your roof is.

To establish the rafter length we calculate the following. Our roof rafter calculator tools are handy for calculating the number of rafters needed rafter length calculator lineal feet of rafter board feed in ridge and sub facia and the total board feet in the roof. Rafter slope min 15 max 45 degrees. Maximum clear span of rafters in metres for roof pitches of between 15 and 45 degrees.

Clear span on plan. Roof pitch between 15 and 22 5 degrees with rafter spacing. 2 175m is your rafter length. This is the distance between rafter centres.

2 4 x 1 1034 refer to image to the right 2 65. The full version allows any size. Maximum clear span of rafters in metres for roof pitches of between 15 and 45 degrees size of rafters in mm roof pitch between 15 and 22 5 degrees with rafter spacing of roof pitch between 22 5 and. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2.

Surveyors and structural engineers utilise data from tables below to help calculate the correct size strength and centres of roof timbers for the required spans and loadings. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. In this example we have a customer with a building width of 4 8m wide and the pitch of the roof is 25. Roof pitch between 15 and 22 5 degrees with rafter spacing strength class c16.

Often you express roof pitch as the ratio between the rise and the run in the form of x 12. Roof pitch refers to the slope which the rafter creates. For pitched roofs flat roofs and ceiling joists.