Cont'd from Page 14

Staples

Staples should be aluminum or stainless steel (type 304 or 316) 16 gauge. Two staples should be driven per shingle or shake with the staple crowns (7/16", 11.113 mm) (miniumn) horizontal to the shingle or shake butt and driven in the same location as nails relative to the sides and overlapping butt line. Staples should be long enough to penetrate the sheathing at least 1/2" (12.7 mm) and driven flush with the surface of the shingle or shake.

VENTILATION DETAILS

The importance of good attic ventilation beneath the roof cannot be overemphasized. Such movement of air will prevent or inhibit condensation of moisture on the under-surface of the shingles or shakes, or on the roof decks. Vents should be provided at the soffits (eaves) as well as gable ends (screened to prevent ingress of insects) or preferably the ridge lines with cross-ventilation desireable. A rule of thumb for adequate ventilation is that the ration of total net free ventilation area to the area of the attic should not be less than 1:150, with compensation made for screens over vent apertures. Attic fans may be beneficial, these supplying additional movement of air in attic spaces. Several examples of construction techniques which provide roof ventilation are shown in Figure 19, Page 16 & Figures 20, 21 and 22, Page 17.