| 1. |
FIXING WALL PLATE TO WALL
If fixing under eave, the wall plate must have a minimum clearance of 30mm to allow for roofing sheets. For fixing
to a flat wall, the height of wall plate should not be any lower than 2550mm from deck level. In most cases it
can be lower, but contact Bullnose Roofing. for more details. Refer
Detail A. |
| 2. |
FIXING SUPPORT POSTS
For best results use "Post Trim" post supports for ease of plumbing posts. For post centre location,
divide length of awning into equal spaces. Maximum post centres using a 200 x 50 beam is 3000mm. Maximum post centres
using a 150 x 50 beam is 2400mm. Greater centres can be achieved with laminated beams. Contact
Bullnose Roofing for details. Fix post supports to deck or concrete pad. Follow instructions in "Post
Trim" packet. Refer Detail B. |
| 3. |
PREPARATION OF POSTS
CORNER POST - Notch out post top on two sides the depth and width of fascia beam. Refer
Detail C.
MID SPAN POST - Notch out post top on one side only the depth and width of fascia beam. Refer
Detail D.
Cutting post to length ensure deck or flooring is level. If not, allow for it when you cut post. The minimum clearance
height of the fascia beam "underside" is 2050mm. Refer Detail D. |
| 4. |
STANDING POST AND FASCIA BEAM
Place post on support base plate. Plumb post with the level and brace. Ensure the rebates on posts are all level.
Fix beam to posts. |
| 5. |
FIXING RAFTERS
THE COMMON RAFTERS - Notch out rafter at the bottom of curve to suit beam thickness and 100mm in depth. Refer
Detail D and E. Fix front of rafter to beam and fix back of rafter flush with top of wall plate. See span
tables for maximum rafter spacings.
THE HIP RAFTERS - Cut 100mm off the curved end. This cut will sit on top of fascia beam and post. Refer
Detail C. |
| 6. |
FIXING PURLINS
The purlin spacing is to be no greater than 1200mm apart as recommended by BHP roofing table. For best fixing of
sheets, the first purlin should be placed 100mm past the finish of curved section of rafter. Refer
Detail I. To fix purlin into position, simply skew nail or screw to rafters and ensure top of purlin is
flush with top of rafter. |
| 7. |
FIXING GUTTER
First test a bulllnose roof sheet. Lay it on framework adn mark a line on fascia beam where sheet finishes. Fix
bottom of gutter 20mm below line mark on fascia beam to allow for sawtoothing (explained later) when laying roof
sheets. Install downpipe outlet. Refer Detail H. |
| 8. |
FIXING ROOFING SHEETS
A carpenter's level should be used to lay the first sheet. Place level on top of curved part of sheet, lift sheet
till it is level. This will give you a sawtoothing effect. Refer Detail F. Sawtoothing
must occur for sheets to remain square and level. |
| 9. |
WEATHERING THE ROOF SHEET
Weathering is to ensure that wind assisted rain does not run over the back of the sheet. with pliers or a shifting
spanner closed down to 2mm, grip valley of sheet and turn up 90 degrees or as far as possible. Refer
Detail G. |
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IMPORTANT
- MGM Structural Curved Rafters have been tested for strength to meet AS1720 design requirements
for a stress grade of F8. The instructions contained here apply to MGM Structural Curved Rafters only and are not
suitable for other rafters.
- These instructions are also based on the assumptions that a) you have building skills, b) the
verandah or its foundations are in place and c) you have completed plans and/or drawings with specified verandah
dimensions and a rafter plan
- Although the diagrams herein show bullnose rafters, the same principles of construction also
apply to concave, convex and ogee.
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