Roof Purlin Design Calculation

Typical tiled roof.

Roof purlin design calculation.

Structural calculations for timber joists timber beams glulam beams flitch beams using the latest design codes. The real purlins shall be checked for deflection in the direction perpendicular to the roof. 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. 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.

The truss is a framework consisting of rafters posts and struts which supports your roof. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. This spreadsheet is to be used to check the adequacy of roof purlins for a specified combination of loads. Trusses can be constructed with smaller sized lumber than rafters and often their cost is not significantly higher than normal rafters.

An example of a complete calculation for a sloped roof is also presented in the above mentioned section. 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. Suitable for uk building regulation approval. 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.

Role of sag rods in the case of both roof purlins and girts the use of sag rods other than for the. 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. 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. Overall stability calculation.

The designis based on the maximum yeild strength mn fysx as stated in the aisc manual 13th ed. Use of manufactured roof trusses can dramatically cut labor costs when framing a gable roof compared to building rafters. Design these elements and the ridge and peripheral fasteners according to the factored gravity loads. Roof purlin design roof purlin design.

As structural members they resist loads and provide lateral restraints for truss members therefore it is important to design them properly against forces.