Roof Purlin Design Calculation

In timber construction purlins are nailed to the rafter or supporting trusses while in steel roof construction they are welded or bolted to the rafters or trusses by the means of cleats.

Roof purlin design calculation.

Trusses can be constructed with smaller sized lumber than rafters and often their cost is not significantly higher than normal rafters. All calculations such as calculating the area of roof the length of rafters or the number of purlins all this information will be presented just in few seconds. 2002 bs 5268 7 6. The important point to keep in mind when you use your truss calculator is that every truss calculation is completely unique and is based on the size of your roof and its specific dimensions.

Calculations to bs 5268 2. The designis based on the maximum yeild strength mn fysx as stated in the aisc manual 13th ed. Overall stability calculation. As structural members they resist loads and provide lateral restraints for truss members therefore it is important to design them properly against forces.

Use of manufactured roof trusses can dramatically cut labor costs when framing a gable roof compared to building rafters. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. 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. You just need to enter properly the basic measured parameters width and length of the roof height or desired angle of the roof and to select type of roof material and type of roof.

An example of a complete calculation for a sloped roof is also presented in the above mentioned section. The real purlins shall be checked for deflection in the direction perpendicular to the roof. Structural calculations for timber joists timber beams glulam beams flitch beams using the latest design codes. Calculation reference roof design structural steel cold form sections.

Suitable for uk building regulation approval. When the roof can not prevent the purlin lateral instability and reverse such as the use of snap in roof panel should be calculated according to the stability formula cross section. Design these elements and the ridge and peripheral fasteners according to the factored gravity loads. The truss is a framework consisting of rafters posts and struts which supports your roof.

Typical tiled roof.