In order to determine rafter lengths, it is necessary to have a thorough understanding of the various markings and measurements on the steel square. The steel square consists of two main components: the body and the tongue.
The body, which is the longer side measuring approximately 24 inches, contains multiple markings and numbers along its edge. On the other hand, the tongue, which is the shorter side measuring around 16 inches, is perpendicular to the body.
To compute rafter lengths, adhere to the following steps:
1. Begin by positioning the steel square on the rafter stock, ensuring that the body is against the board's edge and the tongue extends over the top surface.
2. Align the tongue with the desired pitch or angle of the roof slope. Typically, the pitch is measured in inches per foot. For instance, a 6/12 pitch signifies a rise of 6 inches for every 12 inches of run.
3. Once the tongue is properly aligned with the desired pitch, make a mark where the body intersects the edge of the rafter stock. This point signifies the top of the rafter, commonly referred to as the plumb cut.
4. Subsequently, slide the steel square along the edge of the rafter stock until the desired rafter length is achieved. The rafter length is measured from the plumb cut to the desired run, which represents the horizontal distance the rafter will span.
5. Make a mark at the point where the body intersects the edge of the rafter stock. This point denotes the bottom of the rafter, commonly known as the bird's mouth, where it will rest on the wall plate.
6. Finally, join the two marked points with a straight line to determine the plumb cut and bird's mouth on the rafter.
By utilizing the steel square in this manner, it is possible to accurately ascertain the lengths and cuts for rafters based on the desired pitch and run of the roof. This approach guarantees that the rafters will fit snugly and provide the necessary structural support for the roof.
To use a steel square to determine rafter lengths, you first need to understand the different markings and measurements on the steel square. There are two main parts of a steel square: the body and the tongue.
The body of the steel square is the longer side, usually about 24 inches in length. It has multiple markings and numbers along its edge. The tongue is the shorter side, usually about 16 inches in length, and it is perpendicular to the body.
To determine rafter lengths, follow these steps:
1. Start by placing the steel square on the rafter stock with the body against the edge of the board and the tongue extending over the top surface.
2. Align the tongue with the desired pitch or roof slope angle. The pitch is typically measured in inches per foot. For example, a 6/12 pitch means a rise of 6 inches for every 12 inches of run.
3. Once the tongue is aligned with the desired pitch, mark the point where the body intersects the edge of the rafter stock. This point represents the plumb cut or the top of the rafter.
4. Next, slide the steel square along the edge of the rafter stock until the desired rafter length is achieved. The rafter length is measured from the plumb cut to the desired run, which is the horizontal distance the rafter will span.
5. Mark the point where the body intersects the edge of the rafter stock. This point represents the bird's mouth or the bottom of the rafter, where it will sit on the wall plate.
6. Finally, connect the two marked points with a straight line to determine the plumb cut and bird's mouth on the rafter.
By using the steel square in this manner, you can accurately determine the lengths and cuts for rafters based on the desired pitch and run of the roof. This method ensures that the rafters will fit properly and provide the necessary structural support for the roof.
To determine rafter lengths using a steel square, you need to follow a few steps. First, line up the heel of the square against the rafter's bottom edge. Next, locate the common rafter pitch on the square's body and mark it on the rafter. Then, pivot the square until the desired rise measurement aligns with the mark. Finally, read the length measurement on the body of the square, which will give you the accurate rafter length.
