Frame by Frame: The Roof
There are two types of roof systems commonly in use today:
Stick frame. This is the process by which your framing contractor will use ordinary or dimensional lumber to create the roof frame.
Truss frame. This process uses pre-built wood forms to build the roof frame. No matter which kind of roof framing is used, they both contain one element that you'll need to be familiar with and that's the "pitch" of the roof. The pitch of the roof refers to the angle or steepness of the roofing frame.
"You may find in mountainous areas the pitches are very steep, so they'll get snow shed," said Rod Brewster, a general contractor. "And they'll get very tall attics — and occasionally they'll put rooms in that also."
Note: The pitch is predicated on the height of the building and the type of climate.
Creating the Pitch of the Roof
To create the pitch of the roof, a single piece of wood called a "ridge beam" is placed along the length of the home. Rafters are placed to the top plate of the second floor and joined to the ridge beam. The resulting angle forms the pitch of the roof.
Note: The steeper the pitch of the roof, usually the thinner the rafter will have to be because of the downward pressure.
Unlike stick framing, which is put together piece by piece by your framing contractor and his team, the pre-fabricated piece of framework used in truss framing is applied all at once. It's usually done by using a crane or other heavy lifting equipment. Because roofs require some of the heaviest amount of lumber, trusses have been the roof system of choice because it allows for more flexibility and more complicated roofs to be constructed.
These trusses are pre-manufactured by a truss manufacturer, and they're specifically designed from the plans for your house according to the pitch of the roof.
Like many parts of a home, the style of the roof is up to you. For example, you may want a steep pitched roof or perhaps a flat one. Whatever your choice, make sure to take the regional climate into consideration. Flat roofs are great in climates with little rain, but if you have a pitched roof you'll have the advantage of water draining away more easily.
Tip: Another thing to keep in mind when deciding the pitch of the roof is that a high pitched roof will allow for an attic. In fact, the attic is the actual roof — the space between the roof rafters and the ceiling joists.
Another type of truss that allows for a bit more flexibility in the attic cavity is an attic truss. It's designed to have a clear span in the attic area of anywhere from 12' to 14' wide with maybe 8' in height. This allows for access to either mechanicals in the attic or storage space.