Roof spreading

Structure · Rafters, Roof Joists and Ceiling Joists · printed page 77 (PDF page 78)

Original page Sign in to save

Book index entries

Roof – Spreading Spreading Roofs

Text in the illustration

ridge sags in middle (not at ends - which are supported)
rafter ends bow out in middle
perspective view
rafter slips freely past wall
one possible result
look for cracks here
another possible result
top of wall pushed out with rafter
cross-section in middle of roof

Generated explanation

A perspective view of a gable-roofed house shows the ridge sagging in the middle while the supported ends remain higher, and the rafter ends bowing outward along the middle of the eaves. Two cross-sections illustrate possible results of roof spreading, with dashed outlines indicating displaced positions. In the upper section, the rafters slip outward past the supporting walls while the walls remain upright. In the lower section, the spreading rafters push the tops of the walls outward. Callouts identify the roof-to-wall junctions as locations to look for cracks.

Related illustrations

0410

Roof spreading, dishing and sagging

· p. 74

Three perspective views of gable-roofed houses illustrate different roof deformation patterns. The roof-spreading example shows bowed roof edges, with dashed reference lines indicating straight alignment. The dishing exa

0426

Roof spreading - remedial action

· p. 78

A perspective view of a gable-roofed house shows the ridge sagging between supported ends and the rafter ends bowing outward at midspan along the walls. Two cross sections illustrate remedial options based on ceiling-joi