Framing the Roof

Abstract

The roof should be framed in place, meaning that the caster plate (the bottom plate of the roof framework) is placed on the track with casters intact, and the roof trusses built upon it. Otherwise, the roof could be constructed on a “bench” of sawhorses and lifted into place. This is an extremely difficult operation without the assistance of a crane, because the walls of the observatory (including foundation) are too high for a crew of people to simply lift the roof over and onto the track. Unless you have an army of helpers enlisted to do the job, a group of people cannot lift so much weight over their heads. If you have crane access (the mobile type) that won’t alter the appearance of your lawn, the saw horse “bench” process is the way to go, saving you the arduous task of climbing up a step ladder each and every time you add a framed truss, to nail it in place. Later, when installing the 15 pound roof felt underlay and the corrugated steel roof panels, the requirement for reaching up into the roof framework becomes necessary. This becomes particularly difficult when applying the roof felt and later the steel roof sheets starting at the ridge board, although you can get nailing access through the openings in the trusses and purlins (the metal roof sheets are normally about 30 in. wide).