Roof Ridge Board Thickness

This sizing guide for roof rafters will help determine what you need for your small project.

Roof ridge board thickness.

Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter. There are several variables to consider when determining the proper rafter size. Roof pitch between 15 and 22 5 degrees with rafter spacing strength class c16 size of rafters in mm 400mm 450mm 600mm. For 2 x 6 rafters use a 2 x 8 ridge board and so on.

For 2 x 4 rafters use a 2 x 6 ridge board. Oriented strand board osb or plywood can be used although plywood will provide higher nail head pull through resistance. Ridge boards shall be at least 1 inch nominal thickness and not less in depth than the cut end of the rafter irc section r802 3. The ridge board s length will be the outside measurement of the building plus the length of the overhang at both ends.

Ridge boards can only be used in roofs with slopes from 3 in 12 up to 12 in 12. If your goal is to only calculate the roof height do not enter any numbers in wall height field and only use building width and roof pitch fields. Typically 15 32 inch or thicker panels are required in high wind areas.