Use these two tables for roof rafters with a slope greater than 3 in 12.
Roof truss span tables uk.
Pitched roof timber sizes.
Posi rafters posi rafters combine the lightness of timber and strength of posi strut steel webs to provide a quality roof system that can span further than alternative timber products.
Alpine truss designs are engineered to meet specific span configuration and load conditions.
Total load psf duration factor live load psf roof type 55 1 15 40 snow shingle 55 1 15 30 snow tile 47 30 snow 40 20 snow 1 25 20.
The following tables give details of the allowable spans and spacing for some of the more common timber sizes used in traditional roofing construction.
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.
Finally the truss calculator will compute the best dimensional method to connect the pieces of the truss with steel joints and a bridge.
The same thing is true for the bridge of the truss.
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.
Roof trusses mitek manufactures the steel connector plates used in roof trusses.
For pitched roofs flat roofs and ceiling joists.
The above spans are based on american softwood lumber standard sizes.
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.
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These steel joints are needed to support the overall truss.
The more complex the truss framework is the greater quantity of these joints will be required.
The shapes and spans shown here represent only a fraction of the millions of designs produced by alpine engineers.
All the figures are based on roofing tiles or slates laid on timber laths over sarking felt.
Design manufacture and nationwide supply of bespoke roof trusses and metal web floor joists for over 25 years.