Measure from the point on the blade to the point on the tongueit need to be 14-7/16 inches (commercial roofing). Multiply this by the run of the structure. We're utilizing 10 feet in this example, excluding the overhang. The resulting figure is 144-1/2 inches. We add 12 inches for the overhang to get a last figure of 156-1/2 inches.
Take a look at the rafter board to determine if there is any curve or "crown" in the board. You need to make this very first pattern rafter on the straightest board you can discover. If there is any curve in the board, set out the rafter so the crown is up or facing away from you.
( If the crown were to be placed down, the roofing could eventually sag.) Then lay out the rafter as revealed on the next page. This example is for a roof with an 8/12 pitchPosition the square at the end of the rafter board, with the tongue on your left and facing far from you.
Mark along the backside of the tongue. This is the plumb cut for the roofing system ridge. Procedure form the top of this line down the board to identify the line length, or length of the rafter, less the ridge board. This typically is a 2-by or 1-1/2- inch board, so the measurement is less inches.
Holding the square in the exact same position as in the past, discount to the side of the tongue. This marks the plumb cut at the within of the house wall for the notch (called a bird's mouth) to seat the rafter one the wall plate. Add the length of the overhang beyond this mark and mark it.
In the example shown this is 12 inches. Cut the rafter at the ridge line and at the overhang line. Then hold the square on the plumb line that marks the bird's mouth. Identify the wall density or depth of the bird's mouth cut and make a mark - reroofing. Cut the notch, initially with a handsaw or portable circular saw, and then end up the cut with a handsaw.
Continue moving down the rafter and marking plumb cuts, including any odd figures. One approach of setting out rafters with a square is called "stepping off." Make a duplicate rafter from the pattern. flat roof. Then lay the rafters out on a smooth, flat surface, with a 2-by in between them at the ridge line.
You might wish to check these on the structure prior to cutting the remainder of the rafters. As soon as you make sure these two pattern rafters are correctly cut, mark them as patterns and mark and cut the necessary variety of rafters. If the building has hanging or "fly" rafters for the gable ends, cut them too.
Make sure you thoroughly follow the pattern rafter. A number of years ago I was constructing a two-story building. One carpenter set out and started to cut the rafters. He ended up being ill from the severe heat of the day and another carpenter took control of for the last third of the rafters.
I do not understand if the 2nd carpenter didn't use the pattern rafter, or simply wasn't as exact, however it was an expensive mistake. The brand-new C.H. Hanson Pivot Square makes the chore of setting out a roof rather basic. I wish I had this tool a variety of years and buildings earlier.
It includes its own heavy-duty belt holder that is also created to hold a carpenter's pencil and the guideline brochure. The new C.H. Hanson Pivot Square makes it eady to lay out rafters. this quality tool features its own belt pouch and has dividers for the square, an instruciton handbook and a carpenter's pencil.
Degrees and increase are marked on a blade connected to the pivoting arm. With the common increase figures facing you, and the raised fence on the right, the bottom represents the base of the triangle (the run) and the right side the altitude (the rise). The long adjustable edge represents the hypotenuse of the triangle, or the line length.
Just change the square to the wanted pitch and lock in location with the knurled knob. You can then utilize the square to transfer the angle for the cut to the lumber. Or you can hold the square in place and use it as a durable guide for running a portable circular saw.
Figure out the pitch, then you can set a miter saw or compound miter saw to make cuts in degrees that comply with the desired pitch. The Pivot Square can also be utilized to lay out pitches steeper than 12/12, in addition to to set out hip-valley rafters. These figures are identified on the rear end of the square.