When installing 2 by 4 lumber to existing 2 by 6 rafters add the 2 by 4 width which is 3 1 2 inches to the 2 by 6 width which is 5 1 2 inches for a total of 9 inches.
Extending a roof rafter with cleats.
Use cleats the same length as the width of the new rafter when added to the width of the old rafter.
But it is important that the roof pitch is exactly the same as the existing roof because you will see it from one roof to the other if it isn t.
In this case the framer just needed a longer rafter.
A birdsmouth cut involves taking a notch shaped like a bird s mouth.
Double the tiles at eaves and project them 1 inch over the rear edge of gutters.
As such it s important to have rafters properly secured so these forces don t win out.
Part of this has to do with creating a birdsmouth cut to facilitate the joining of top plate and rafter.
The cost of extending my 30 foot long roof overhang 14 inches was 340 or 11 50 per running foot for materials.
A general rule of thumb for cantilevering rafters meaning they will have no vertical support at the ends is to have twice as much rafter attached to the original rafter as the unsupported length.
A good estimate for a contractor to do this same roof overhang extension would range from 50 to 85 per running foot.
In this case the rafter as a whole is actually stronger than it would have been because the splice is more than adequate and the plywood adds to the strength.
If you choose to go with the same width it will be more difficult to execute without a noticeable difference or bump in the roof between the old and the new.
For minor additions the contractor can remove the side of the roof and attach additional pieces of wood to the preexisting rafters before refinishing the roof.
Choose to extend the preexisting rafters to add 2 9 inches 5 1 22 9 cm.
To lay out the plumb cut take measurement b from the full scale drawing figure 3c and transfer its dimensions to the rafter on both sides of the centerline of the birdsmouth as shown in.
Attach 1 2 inch wood cleats to both sides of the existing rafter.
Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes.
If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.
This cost did not include any labor or waste disposal fees.
Secure each tile with two large head roofing nails.
The gravitational forces on a roof cause the rafters to want to push outward.
Pictured at left is a 2x6 rafter spliced together using 3 4 plywood.
It is always better to have a large rafter rather than be concerned with a sagging roof.
