After the ceiling frame is totally complete and the rafters have been set out and cut, follow the steps below:
Fig. 65 Completed ceiling frame
STEP 1 Measure the length of the ridge and cut to length or join lengths together, as previously shown.
Note:Allow extra length for gable overhang as required.
Lay the ridge on flat and place the top edge flush with the ends of the ceiling joists.
Using a square, transfer the rafter positions onto the edge of the ridge and square them down the face of one side.
End of deep hanger strapped with loop iron and supported on a ceiling trimmer
Ceiling dogs on alternate sites of hanger
Smaller sectioned hangers over short spans
End of hanger bolted to gable stud to prevent twisting
Ceiling joists
Rafter positions marked onto ridge
Fig. 67 Fixing the first pairs of rafters to the ridge
Fig. 68 Fix off the remaining rafters
STEP 2 Erect a pair of rafters for each end of the roof. Nail the feet of each pair to the plate with the plumb cut ends butted together.
Place a temporary nail at the top of each pair of rafters for stability.
Lift the ridge up between the rafters until it is flush with the top edge, or to a marked straight line, then nail through from one side into the end of one rafter with 2/ 75 mm nails.
Align the opposing rafter and skew nail from the opposite side using 2/ 75 mm nails.
STEP 3 Plumb one end and attach a temporary brace, to prevent racking, and then attach a string line along the top of the ridge to ensure it remains straight while the remaining rafters are nailed into position.
Note: Provided all rafters are exactly the same lengths and the side wall plates are straight, then the ridge should automatically finish straight.
Temporary nail
This rafter is nailed first, from the other side
Ridge
Fig. 69 Complete the assembly of the structural frame
STEP 4 Set out and fix purlins into position as required, then cut and fix the struts for the whole roof.
Set out, cut and fix collar ties on top of purlins, bolting or nailing them as required.
STEP 5 Fit permanent wind bracing. This may be in the form of opposing timber braces onto an internal wall or metal speed bracing over the surface of the rafters.
Rafter
Collar tie scarfed around rafter
Purlin Inclined strut
Inclined opposing wind braces
Speed bracing
Fig. 71 Boxed gable studding and framing complete
Fig. 72 Gable end studding and framing complete for raked eaves
STEP 6 Cut and fix gable studding into place to suit wall stud spacings and sheet cladding joins.
A pair of rafters and a bottom chord or tie forms the boxed gable frame. The studs are cut around the rafters and tie.
Raked eaves on a gable end have the addition of a raking plate on either side, fixed under the line of the rafters. Outriggers are supported on these raking plates with short trimming rafters cut between them, for rafter continuity.
Gable studs checked out around the rafter and tie
Bottom chord or tie
Eaves trimmers
Gable studs placed at centres equal to wall framing or sheet cladding joins
Rafter trimmers cut between outriggers
Outriggers
Raking plate for fixing of cladding Gable studs
cut onto top plate
Gable studs spaced at centres equal to wall framing or sheet cladding joins
Fig. 73 Marking the width of the eaves
Fig. 74 Marking the ends of rafters to a line
STEP 7 To determine the eaves width, it will be necessary to calculate the drop-off position, unless these dimensions are given. Refer to previous details.
Set out and mark the line of the overhang by measuring horizontally from the outside of the wall frame. Plumb a line down the face of the rafter ready to cut.
STEP 8 Plumb a line down, the same distance out, at the other end of the roof. Drive in two temporary nails on the top edge of the end rafters and attach a string line.
Work along the rafters marking plumb down from the string line with a spirit level.
Mark the face of the rafter
550
String line plumbed down
Fig. 75 Fitting the fascia ready to receive gutters
Fig. 76 Fitting the barge to enclose the end of the gutter
STEP 9 After the ends of the rafters have been cut plumb to a straight line and the eaves soffit bearers fitted, cut and fit the timber or metal fascia ready to receive the gutter.
The top of the groove should be in-line with the top side of the eaves soffit sheet.
The top of the fascia will project above the top edge of the rafters to provide a bellcast. The bellcast ensures that the first course of tiles will have the same pitch
as the remainder of the roof and the distance above the rafters should be equal to the thickness of a tile batten plus the thickness of one tile.
STEP 10 Once the fascias are fitted and the gable ends are clad, cut and fix timber barges or Colorbond metal barge soakers.
The bottom edge of the timber barge is fixed flush with the bottom edge of the fascia and run past the fascia to enclose the end of the gutter. They will require a timber bellcast infill piece to be attached to the top edge.
Soffit bearers fitted from fascia to wall frame
Fascia double skew nailed to prevent it from being easily pulled off
Top of groove flush with
Barge attached to gable rafter
End of eaves boxed Timber fillet
placed on top to form a bellcast Quad gutter
fitted to fascia