Building roof trusses
Learning how to build your own roof truss components can save a lot of money because truss companies charge a lot for construction and delivery of trusses.
A roof truss is made strong because it uses leverage to maintain the weight of the roof.
Trusses are connected with glue and mending plates and pressed while they are drying.
Mending plates keep the truss pieces from moving. These are plates that have small points on the underside that are pressed into place.
The roof pitch is described as a slope. This is calculated by how many inches of slope are in a foot.
Trusses are custom made to fit the exact span of the walls in a floorplan. Even though they are custom made, they are easy to make yourself. They are just 2X4 lumber cut at angles to fit into a truss design for strength.
This page talks more about barn-type trusses, but there is a good instructional page for building
normal trusses here.
Gambrel roofs make a lot of sense because they add extra living space for minimal cost and they are strong. If the roof won't have a load-bearing wall supporting it in the middle then the slope needs to be a 30 and 60 degree combination to make it the strongest.
You may want to add extra bracing and support at the knee of the truss. Gambrel trusses are quite different than normal trusses. The load is usually put on the knee of the roof. That is why the angle is so important.
Dormers look nice with gambrel roofs. They add light and make a nice view. Dormers also have their own trusses that are easy to make.