Verandah / Carport Spans

It was and still is common practice for the roof sheets on Curved verandahs (Bullnose or Concave) to span from wall to fascia for verandahs up to 1800 mm wide, despite some Technical Data stating the maximum single span width should not exceed 1200 mm. Most Councils accept that "curving quality" corrugated roofing will satisfactorily span 1800 mm without rafters, but wider verandahs / carports require supporting rafters and purlins.

Rafters and Purlins are generally spaced further apart than those generally used with Standard corrugated roofing.

For Bullnose verandahs 1600 mm – 1800 mm wide, a height difference (from the top of the fascia beam to the top of the wall plate) of between 450 mm - 650 mm is most common and a satisfactory appearance can be achieved. Shallower depths can be used but the balance between seeing both the curved and straight section of the bullnose sheet may be jeopadised.

I make the shaped rafters (Bullnose or Concave) for our jobs, so I can make rafters with our standard curve or I can make them with other curves, e.g when matching an existing Bullnose curve is required. The rafters are shaped to suit the curve (radius and length of bullnose curve on the Bullnosed roofing; or radius / depth of curve on Concave roofing); and the purlins are fitted between the rafters, enhancing the appearance. I generally cut the curved rafters from "LVL" beams, but I also make "Bullnose" rafters from "Oregon". Bullnose rafters made from Oregon cost more (approximately $70.00 - $80.00 per carport rafter) than rafters cut from "LVL" beams, but have a smoother appearance.

"When I make the Bullnose rafters from Oregon, I glue and dowell joint another piece of timber to the rafter end and cut the Bullnose curve from the laminated end. "LVL" beams are primarily intended for use inside a roof structure, and not be visible. The relative roughness of the veneers is not critical in there primary intended application."