But 6/17 isn’t expressed in a way that’s useful in construction so it needs to be converted to a value per foot. So, for this roof, the rafters have a pitch of 6/12, and the hips and valleys have a pitch of 6/17. The general rule of thumb is that for every 12 inches in run for your rafters, hips and valleys have about 17 inches in run.
Calculating the pitch of the hips and valleys is relatively simple when both intersecting roofs are the same pitch. If your plans don’t show the pitch of hips and valleys you’ll have to calculate it on your own with the information that you do have. If the rise is the same but the run (and therefore the span) is different, then hips and valleys will have a different pitch. Their horizontal distance will always be longer than that of the main rafters. When doing so, hips and valleys will always be the hypotenuse or the longest edge of that triangle. (Assume no overhang) 18 Open web steel joists are typically attached to the structural steel frame _.To simplify this, envision a section of the roof with a valley or a hip as a right triangle. 30 The number of sheets of plywood sheathing needed for a house 30" long with a span of 24' and with 8" ride per foot of run is _. In cold climates where snow accumulates The number of common rafters needed to frame a 20' long table roof for a house framed on 16" centers with no overhang is _. A vapor barrier A waterproof underpayment should be used along roof edges _. The most common form of the rafter is known as the fink, or ‘we trussed rafter in modern house construction. 15 pound immediately after nailing the plywood sheathing on a roof frame, you should install_.
Experienced crane operator When placing underpayment over sheathing for roofs with a slope of 4" or less, the commonly used roofers felt is _. Bar joists Positioning or installing trusses must be done under the supervision of a(n) _. Diagonal braces Trusses that carry other trusses or support a large area of roof framing are called _. Straighten and strengthen the ceiling joist When framing a gable end, it is necessary to measure and cut_. Roof openings A strong back is installed to _. Purlin Double trimmers are used when framing_.
Common rafter manual#
Using rafter tables in the instruction manual A rafter support that parallels the top plate and the ridge board is known as a _. When you are using a speed square the length of the rafter is determined by_. 12" To determine the final measurement when laying out a common rafter, it is necessary to deduct_. 14'-8" The rise per foot of run of a roof with a pitch of 1/2 is _. 9 in 12 The length of a common rafter for a 20' wide building with a 10" rise per foot of run is_. These are used in large buildings like the traditional large old barns in the US. Underpurlin: Horizontal beams supported by posts and used to support the mid-span of rafters to cover longer spans. While the most common gable roof can be constructed using only one type of roof rafter, the most complex roof designs can use a combination of all seven roof rafter types.
Common rafter series#
The steeper the roof A roof that rises 9" for each foot of run has a slope of _. Rafter: One of a series of diagonal members of the truss that meet at the apex in order to support the roof deck and its loads. There are basically seven different types of roof rafter designs used to create a roof: common, hip, hip jack, valley, valley jack, cripple jack and flying hip. Cripple jack rafter The greater the unit of ride of the rafter, _. 4" A rafter that touches neither the ridge nor the plate is called a _. Rub A roof with slope of 4 in 12 has a ride per foot of run of _. 2/3 Half the distance from the outside of one exterior wall to the outside of the opposite exterior wall is the _. Unit ride The pitch of the roof that has rise of 8' and a run of 12' is _. The distance a rafter rises vertically for each foot of run is known as the _.
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