How To Make Roof Rafters

Build a fink truss to bolster a floor roof or deck.

How to make roof rafters.

The roof rafters provide integral structural support to the roof. The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial. For example if your roof is 24 feet long you can have a 4 12 roof pitch. In a fink truss the internal joists are arranged in a w shape ensuring even weight distribution from one end to the other.

The ridge end of the rafter and often the eve end will need to be cut to the angle of the roof slope. How to build a shed roof step by step. This marks the notch or bird s mouth cut of the rafter which rests on top of the exterior wall. Before you begin building rafters you need to determine that you have the right tools materials and measurements.

Building installing roof rafters. Measure from the bottom end of the plumb cut line marked in step 5 and make a mark at 2 inches. Here we have a wood framed gable roof. When you cut the rafters you ll need to make 3 separate cuts.

This video shows how to make roof rafters with a rafter square and or a speed squ. From this measurement mark a line square to the plumb cut line to the bottom edge of the rafter. Fink trusses were originally invented for the purpose of beefing up bridges but many contractors now use them to increase the strength of interior structures. Floor beam span tables of residential structural design we will now look at roof rafter and beam design.

Before you cut your boards you ll need to measure the width of your building and calculate the exact length of each rafter. This video shows how to make roof rafters with a rafter square and or a speed squ. You can use common rafters on any shed roof but they make the most sense when constructing a gable roof or lean to type shed roof where they can sit on or attach to top plates of a wall. To lay out a common rafter you need the pitch of the roof expressed in units of rise per foot of run in the gable roof example shown here a rafter with 6 in 12 pitch rises 6 in.

Lean to rafters then connect to a ledger board against a wall of another shed or house. The first step in building the roof rafters is to cut one rafter board to length with the ends angled properly and then to mark and cut the birds mouth and seat on the rafter. The first thing to determine is the pitch your roof will have and the span your roof needs to cover. For every foot.

Let s consider a basic gable wood roof framing design.