Rafter length is the shortest distance between the outer edge of the top plate and the center of the ridge line. A carpenters framing square includes some tables stamped right into the tool itself. Hes proclaimed for years that the best method for finding the correct lengths for hip rafters and laying out the back bevel angles, hip rafter side cut angle, was in the swansons blue book. If your lumber is this bad then i would suggest taking it back and finding a new supplier of materials for your roof layout. How to lay out a hip rafter explained by a holly hill sc home. Pivot the layout square so that the number 7 on the common scale lines up. Though, i did note that for the kindle fire needed you to download a free pdf reader. Sep 29, 2017 using a common rafter, i mark and cut the ridge, birdsmouth, and rafter tail to create my jack rafter pattern see illustration, above. Plan books, internet sites, architects, or builders may provide a. A modern handbook for roof framers by david mahin mcintire give yourself an edge over the competition.
Hip and valley roofing property and building inspections. Calculate the ratio of the rafters horizontal run to its slope length. If your lumber is this bad then i would suggest taking it back and finding a new supplier of materials for. Framing square rafter table guide how to figure roof rise.
They are generally inclined members spaced from 16 to 48 in, apart that vary in size, depending on their length and the distance they are spaced. Label and identify the parts of a roof framing plan. Parts of a roof a ridge board is a horizontal member of the roof frame. With the inch rise calculated, we are now ready to layout each type of rafter.
Roof plan a roof plan is commonly drawn to a scale of 18 inch per foot or 116 inch per foot. Roof features associated with basic roof framing terms are shown in figure 22. This is the horizontal distance measured from the centre of the ridge to the outside of the wall plate. A truss is formed when structural members are joined together in triangular configurations. Note that this is parallel to the nose line of the finished stairs, but is not the same as the nose line. The truss is one of the basic types of structural frames formed from structural members.
Both the common rafter and the hip rafter will have the same run using the layout method. You can see that for any rafter, the rafters run is the horizontal distance spanned by the rafter from the center of the ridge to the outer edge of the top plate of the wall. Scope hese span tables for joists and rafters are calculated t on the basis of a series of modulus of elasticity e and bending design values f b. Jul 09, 2017 how to layout and cut hip and valley roof rafters. Click any image to enlarge it seems that most of the others used a rafter length book, or some sort of book reference, to.
This illustration shows an exaggerated crown to get my point across. Besides its unique appearance a gambrel roof also serves to maximize the usable floor space in the attic area. The rafters carry the applied loads to the exterior walls. Objectives define ridge board, rafter, hip, valley, sheathing, fascia, soffit. Roof rise this should be calculated from the base of the roof to the highest point of the roof gable the peak. A pattern book for neighborly houses architectural patterns d colonial revival houses reflect the renewed national interest in classicism which occurred in the late 19th century. The image at left shows a hip rafter with a run of 4 8 12 the span. Print full scale rafter cut templates and birdsmouth templates fold template over rafter to mark or cut through. Shiften or swansons blue book richard birch and i are having a discussion on shiften.
Common rafter full scale templates print and fold over. Objectives define ridge board, rafter, hip, valley, sheathing, fascia, soffit, dormer, and pitch. Drawing by americad analyze load paths to ensure they go down to a foundation connections connections connections roof, floor, and wall assemblies beams, columns, headers lateral load resisting system diaphragms, shear walls, collectors, struts, anchorage, overturning analysis footingsfoundations. Smartjoist design guide 3 the feeling that is identified when a person walks on a floor is very subjective. The architecture created for the 1893 worlds columbian exposition in chicago is a famous example of this revival.
I was happy with most of the dvds and books, but will holladays dvd program, roof framing for the professional, was the best on the subject, and he goes a little more indepth than the others i purchased. Roof types, development of plan shapes and member positions are explained. Refer to as 1684 or timber framing manual for tiedown details. It should also be noted that the lower the slope of the rafter, the greater the axial compression in the rafters. Hes proclaimed for years that the best method for finding the correct lengths for hip rafters and laying out the back bevel angles, hip rafter side cut angle, was in the swansons blue book that you get when you purchase their speedsquare. Draw a line to connect all the points on the stair stringers. Become a faster, more accurate, and more efficient roof framer with the rafter book. You can see that for any rafter, the rafters run is the horizontal distance spanned by the rafter from the center of. Speed the job of rafter or angle layout by using our. Roof framing terms are related to the parts of a triangle. Strut should bear on a support such as an internal wall. No need for special software that is special to one operating system or another. Cuts are given with framing square layout and degree settings for cuts with skilsaws, and with degree settings for compound miter or radial arm saws. Calculating roof geometry was made much more simple for me after reading a different approach to rafter layout by john carroll.
To make it easier, before you start to measure, mark and cut, print these templates, fold over some scrap wood same size as rafters and cut through the paper to form the correct plumb and side cuts for common, hip and creeper rafters. Design of industrial truss university of asia pacific. Detail a typical arrangement at junction of rafter, purlin. Wcd1 details for conventional wood frame construction. Aug 14, 2015 i was happy with most of the dvds and books, but will holladays dvd program, roof framing for the professional, was the best on the subject, and he goes a little more indepth than the others i purchased. Check the rafter material and take note of the crown. When people say the floor bounces, it may be vibrating. For additional copies of this instruction manual contact your. A rafter that runs from a hip rafter to a valley rafter, perpendicular to the roof ridge see figures 1 and 8. Mar 27, 2008 rafter layout this article will discuss a gable roof, without valleys or dormers, because its the most common and the easiest for a firsttime builder to tackle.
This article explains how to make quick use of a framing square and its imprinted data to get some basic roof measurement data like roof pitch or slope, rafter lengths, and end cuts. The plan reader should be familiar with roof styles and the rafter components of these designs to calculate roof framing materials and framing labor. Rafters act more like the top chord of a roof truss than as a roof joist. The typical section shows the column and rafter arrangement, purlin, girt and frame brace locations, bolt sizes and numbers, inside clearances and the layout of sidewall panels, roof panels and light transmitting panels. Add all the common and jack rafter horizontal run lengths them multiply by the factor. It can be difficult to visualize rafter plumb and side cut angles and how the common, hip and creeper rafters all fit together. Would the framing labor and material for a steep pitch victorian roof be the similar to a colonial.
Use square to draw seat cut line from bottom edge of rafter to intersect building line. Span is the horizontal distance between the outside. The rise, or height of the roof at its peak, is the altitude of the triangle. Hip and valley roof compound angle formulas and geometry. Way back when i was quotedi found an old framing square poster that shows the 16 used for one leg of the layout. The general arrangement of rafters shown in the larger drawing. The roof framers field manual blue palmetto home inspection. The ridge board is nonloadbearing and merely provides the point of connection for the opposing rafters and is only a nominal 1 thick.
After you determine the rise, span, run, line length and pitch, the next step is to lay out the rafters, or mark the cuts on a pattern rafter to create the roof. The hip side cut, drawn on the top of the unbacked timber, is found on the tangent plane. They do for the roof what joists do for the floor and what the studs do for the wall. Roof structures roofs section1 module 3 sheet 12section double roofs a double roof is a roof whose rafters are of such a length that they require an intermediate support. Sep 03, 20 shiften or swansons blue book richard birch and i are having a discussion on shiften. This support is usually a beam which is secured under the rafters at a point half way between the ridge and the wallplate. At the top of the rafter, place the rafter square on the face of the rafter as in figure 7. A different approach to rafter layout fine homebuilding. If the lumber is not straight, always put the high or crown side up. Heres how to make sense of all the numbers on your square and get the most out of this tool. The fascia can be make from either 1x or 2x material, depending on the need to resist warping.
They mainly carry compression but they may be subjected to bending if purlins are not provided at panel points. To make it easier, before you start to measure, mark and cut, print these templates, fold over some scrap wood same size as rafters and cut through the paper to form the correct plumb and side. A fascia is a trim board placed at the end of the rafter or truss tails and usually perpendicular to the building wall. Thanks so much for the rafter video it makes laying them out a breeze thanks again reply. How to lay out a hip rafter explained by a holly hill sc. Lay device on incline and hit start measuring to directly measure. This is measured along the top edge of the rafter taken from the centre of the ridge to plumb over the outside of the wall plate.
Select gambrel roof from the roof type dropdown list or click on the appropriate toolbar button to calculate a gambrel roof. The following illustrates a typical frame crosssection and. Sign up for eletters today and get the latest howto from fine homebuilding, plus special offers. Roof structures roofs 12section module 3 sheet 12 flush eaves in this method of. Pivot the layout square so that the number 7 on the common scale lines up with the edge of the rafter. Rafter layout rafters are framing members that support a roof. In the absence of a purlin the rafter span extends from wall plate to ridge board. The framing of a basic gable roof is based on a rightangle triangle, and the various roof framing components fit the triangle. This is because hip rafters rise from the corners of the building at a. This is because hip rafters rise from the corners of the building at a 45 degree angle diagonal.
Used by carpenters union apprenticeship programs from hawaii to new york. Irwin rafter square reference guide complete instruction book. How to layout and cut hip and valley roof rafters youtube. Jun 07, 20 the rafter square, or speed square, does more than mark perpendicular lines. Step 2 lightly draw the outline of a hip roof on this area. The difference is that well use 17 instead of 12 to lay out the hip. Allow for ridge thickness when determining rafter run to outer wall. You can use a framing table or website to calculate your rafter lengths. The rafter square, or speed square, does more than mark perpendicular lines. Terms birds mouth pitch rafter ridge board slope span.
Nov 09, 2012 thanks so much for the rafter video it makes laying them out a breeze thanks again reply. Using a common rafter, i mark and cut the ridge, birdsmouth, and rafter tail to create my jack rafter pattern see illustration, above. Richard lind, everts lind enterprises, lunenberg, n. Third, this method typically leaves the layout and cutting of the rafter tail for later, after the rafters are installed. The point at which all the rafters are attached to. The roof framers field manual is presented as a pdf. A mastery of roof framing with hip, valley, and jack rafters is what distinguishes the true hip rafters 18. A truss consists of a group of ties and struts designed and connected to form a structure that acts as. Similarly, hip and valley rafters provide the point of. This guide uses nominal member size, but it is important to note that the designer must apply the. Additionally, compression perpendicular to grain design values f c. Discover the pros and cons to multiple roof designs. Refer to the figure as you study the terms discussed in the next paragraphs. Starting at the upper end of the rafter, i mark 18 12inch centers at 18 12 in.
Calculating roof material from rafter plans the roof plan shows the rafter direction and spacing but not the rafter length. For more photos, drawings, and details, click the view pdf button below. The first approach to achieving a strong, durable struc. A gambrel or barn style roof is simply a gable roof with a change in slope partway up the roof. Roof design roof design is a major feature of a houses architectural style. A rafter that runs from the top of the wall plate to a hip rafter at 90 to the wall plate see figures 1, 8 and 14. Hip and valley roof compound angle formulas and geometry howdy all. This will allow a ventilation gap to be formed so that a continuous. Select gambrel roof from the roof type dropdown list or click on the appropriate toolbar button to. Design of industrial steel building by limit state method.
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