If you re building rafters and aren t sure where to start when determining the length of your lumber you re in the right place our rafter stock size calculator shows you how long your rafters should be so you ll know what you need in terms of framing lumber dimensional lumber studs and more.
2 x 4 roof rafters in houses.
Here we have a wood framed gable roof.
If you live in an area that requires a shed roof rafter to support a heavy load then an spf rafter can only span 7.
As mentioned above a 2 4 spf shed roof rafter can span 11.
Before you cut your boards you ll need to measure the width of your building and calculate the exact length of each rafter.
If you re framing a gable roof on a new house or building a shed or even a doghouse with a gable roof you ll need to cut a number of roof rafters.
If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.
It is always better to have a large rafter rather than be concerned with a sagging roof.
The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.
A collar tie or beam figure 7 7 is a piece of stock usually 1 x 4 1 x 6 l x 8 or 2 x 4 fastened in a horizontal position to a pair of rafters between the plate and the ridge of the roof.
The roof rafters provide integral structural support to the roof.
An syp rafter can span 11.
Trusses use webs of 2x4s within the truss structure to support the roof.
My shed is 8x14 built entirely with rough 2x4s.
Let s consider a basic gable wood roof framing design.
Will 2x4 rafters 24 inch on centre hold up my 8 x 12 shed.
Most codes and specifications require them to be 5 feet apart or every third rafter whichever is less.
Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes.
Both of these are for light roof loads.
Skinned with 7 16 osb and vinyl siding.
Floor beam span tables of residential structural design we will now look at roof rafter and beam design.
1 3 of the way from each in to keep it from spreading from snow load.
Built on 4 12 pitch roof with 1 2 ply decking and shingles.
Just enter the dimensions of the roof rise and run to get started.
A truss on the other hand is only made up of 2x4s and is often pre fabricated in a factory.
Rafters are on 2 ft spacing.
I put 2 2x4 joist about.