Roof Purlin Deflection Criteria

Mean roof height is not greater than 40 feet.

Roof purlin deflection criteria.

For sake of discussion we will assume a minimal roof snow load of 20 psf pounds per square foot and a 4 12 roof slope. The cos of the purlin spacing is because the load on the purlins is vertical and the purlin spacing is with the run of the roof. Monorail crane mr beams. This post will be focusing on design of steel purlin using cold formed sections.

Roof rafters roof joists and roof beams. Z section purlins 10 c section trimmer 51 side rails 28 7 metsec uk leaders in the design and manufacture of engineered and bespoke purlin and side rail building solutions. Therefore a purlin should be adequately strong to withstand the loads it will encounter during its design life and should not sag in an obvious manner thereby giving the roof sheeting an undulating and or unpleasant appearance. Plaster or gypsum board.

For example the allowable deflection of a 12ft span floor joist with plaster l 360 is 0 4 12ft divided by 360. Dead load will be the actual weight of the roof steel and the roof purlins. Plaster or gypsum board. Top running crane trc beams.

Allowable deflection as an expressed ratio of the clear span. The attached list of criteria is met. Introduction and components roof systems 10 23 eaves beams 24 27 side rail systems 28 53 ancillary items 54 59 load tables 60 78 mezzanine floor systems 79 85. Other than plaster or gypsum board.

1x skip sheathing is. If that same joist had gypsum ceiling l 240 the allowable deflection is 0 6. Table r301 7 allowable deflection of structural members. Underhung crane uhc beams.

3 mezzanine beams and joists.