Floor beam span tables of residential structural design we will now look at roof rafter and beam design.
Pitched roof timber span tables.
The following tables give details of the allowable spans and spacing for some of the more common timber sizes used in traditional roofing construction.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.
Continuing on from part 3.
Eurocode 5 span tables for solid timber members in floors ceilings and roofs for dwellings 3rd edition.
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.
The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.
Span tables for flat roof joists to bs 5268 7 2 imposed loads of 0 75 kn m for maintenance and snow load are applicable where there is no permanent access no fixed ladder or staircase and most areas where the altitude does not exceed 100 metres refer to bs 6399 3.
Trada eurocode 5 span tables 3rd edition bs 8103 3 7 2 3 design of pitched roofs the sizing and spacing of members shall ensure structural stability and provide restraint to the structure without undue movement or distortion.
Span tables for solid timber joists.
Surveyors span tables for designing roof rafters.
Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run.
Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch.
For timber floors between homes.
Here we have a wood framed gable roof.
Also available for the android os.
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.
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
For pitched roofs flat roofs and ceiling joists.
The section sizes are based on regularised als or cls timber.
All the figures are based on roofing tiles or slates laid on timber laths over sarking felt.
Pitched roof timber sizes.
