Swanson 25 cm metric speed square carded with english french. To work out the second length of the rafter so that it runs past the brickwork and can have a fascia board fixed to it, we need to work out the overhang measurement. The roof framers field manual is presented as a pdf. With rafter depth of 200 and birdsmouth depth of 29 the rise from top of wall to top high end of rafter 744. Well known throughout the industry as the little red roofing book, it can be or should be found in every roofers toolbox. This is the rafter length from the top cut to the seat plumb mark. This 60page book has what is needed to get the job done accurately. How to measure roof rafters including the pitch and birds mouth seat cuts captioned accbct. There is an old book that is called the full length roof framer by a. The length of rafters obtained from tables are to the center of the ridge. Layouts and degree settings are given for cuts that always give roof framers. For a run greater than that given in the tables, add any two runs that will equal the desired run, then find the respective lengths for those two rafters and add them together.
Calculate hv rafter lengths, also hip and valley jacks, for both regular and irregular pitches, backing bevels, sheathing cuts, and compile the material list. Or i can tell you the rafters should be 45 58 long from ridge to seat cut. The most basic thing a roof cutter needs to know and understand is a rafter length is simply the hypotenuse of a right triangle, and the er is the base of the triangle. This calculator is to be used as an estimating tool only. Now, when we turn to the 30 page in the rafter ready reckoner and when looking up the common rafter lengths, one of the things it tells us is. Blackfilled graduations stand out against a matte finish for easy reading.
Hip roof framing calculator with rafter angle cutting. Measure or calculate the horizontal distance the rafter will span, starting at the outside of the wall on which it rests, including any board ing on. The speed square includes the swanson blue book of rafter length and roof construction and also features markings for using the swanson onenumber method of rafter layout. Nov 09, 2012 effective run is the run span2 minus the ridge deduction usually the ridge board2, and is the dim used to calculate the rafter length. To the right, read the column headed common rafter length for the rafter. 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. Use the same dimension a along both sides of the hip rafter to mark off the long point of the hip rafter. This book is usually included when you purchase a swansons speed square. Common rafter length spreadsheet framing contractor talk. Effective run is the run span2 minus the ridge deduction usually the ridge board2, and is the dim used to calculate the rafter length. A hip rafter is laid out just like a common rafter with a few twists. Input the rafter span on the flat, eave overhang and pitch of the roof. Hip roof framing rafter cut angle template diagram if using a circular saw or compound miter saw, set saw bevel angle to 45 to obtain creeper and hip side angles.
We bought a couple more books to give to others in the trades. To figure out the rafter length from ridge to the seat cut, you take the run and times it by the number 6 pitch on the framing square, minus 34 which is 12 the thickness of the ridge. Sep 06, 20 one length method by richard birch richard birchs method,one length method, that he developed from the swansons blue book. Publisher is not liable for errors or omissions in this book. The overall length of the roof or a common rafter, from the base to the ridge, is calculated by squaring the run, adding it to the square of the rise, and finding the square root of the sum. Ive been framing for a while now and most things are pretty cut and dry with the exception of jack rafter spacing on different roof pitches. 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. Easily move materials across solid or soft surfaces these carts are constantly in use in our shop. When i have an a california the same pitch i just use my rafter book. This calculator helps you make the rafters of the suitable sizes required for your roofing. How to measure roof rafters including the pitch and birds.
If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. Common rafters are shortened 12 the ridge thickness. Weather youre building a shed roof or adding a dormer to your second story, it is important to choose the proper size rafter. M easure the rafter length along top edge of rafter. If you plan on doing rafters andor stairs go pick up swansons little blue book for rafters and stairs. He is very happy with the condition of the books and that they arrived in a timely manner. It seems you are determined to figure out the rafters using long hand math. Improved methods for laying out and cutting hip and valley rafters are alone worth the price of the book. Usually on the houses i frame, they have an 8 on the main roof with a calafornia a on top, which is a 12. Click the button to calculate the stock size needed for this job. Includes markings for swansons onenumber method of rafter layout, and is packaged with the swanson blue book of rafter length and roof construction.
Lengths and cuts of rafters the first step is to lay out a roof plan on a board or sheet of drawing paper, to a scale of, say, 1 12 in. Easy as all get out to draw for the designer a royal body and mind in the field. Measure or calculate the horizontal distance the rafter will span, starting at the outside of the wall on which it rests and including any boarding. For sale is this pair of booklets for construction. Rafter is a sloping beam usually wood that supports a pitched roof. In estimating the total length of stock for a rafter having a tail, the run of tail or length of lookout must be considered. Using the 7 inch rise table and our 15 run, the common rafter length is 17 43. When building a roof, how do you calculate the length of the rafters. Plan view the plan view is a view looking straight down on the roof measuring line the length of a rafter is measured and laid out on a measuring line on the rafter. Use our online rafter length calculator to quickly compute the length of the shed roof rafter by entering the measurements of overhead, length of roof span, pitch or angle. Rafter span tables use these tables to determine lengths, sizes and spacing of rafters based on a variety of factors such as, species, load, grade, spacing and pitch.
The lengths of rafters obtained from the tables are to the center at the ridge. A carpenters framing square includes some tables stamped right into the tool itself. A modern handbook for roof framers mcintire, david mahin on. Use the calculator below to determine rafter length. How to calculate rafter lengths for gable, hip and valley rafters. Use the same dimension a along both sides of the hip rafter to mark off the long point of the hip rafter top back bevels. Measure from the plumb line shifted at the foot of the hip rafter using the hip rafter length to ridge dimension, 29 14. Explaining the entire process for doing this quickly becomes too convoluted for this overview. How to calculate the length of roof rafters captioned.
In our example an 8 inch rise is used, therefore find the 8 inch rise table on page 47 and go down the left hand column headed run ft. Line up these marks with the plumb line minimum rafter length and the horizontal part of heel cut lies along degree edge. Once you know the appropriate lengths, you will be able to determine the total cost of your roof project. Enter the value for the roof width outside to outside in feet, inches, and. Calculate the length of a rafter from the roof slope ratio of inches per foot, and a building width measurement. Plus md instruction book roof construction and rafter lengths with easy to read rafter length tables for all types of rafters. It seems that most of the others used a rafter length book, or some sort of book reference, to get the length of rafters, jack rafters, etc. The complete pocket reference to roof framing 2nd edition.
The swanson speed square exclusively made with metric the swanson speed square exclusively made with metric measurement first made by swansons founder in 1925. Richard birchs method,one length method, that he developed from the swansons blue book. An easy to read handy pocket guide to roof construction. This sizing guide for roof rafters will help determine what you need for your small project there are several variables to consider when determining the proper rafter size. Stanley has the manual for their quicksquare online and i found a public copy of the swanson speed square manual see links below. With the saw bevel angle set to 45, cutting hips and creepers at the plumb cut angle will produce correct side angles. When laying out rafters as shown in figure 4 lets assume a 5 dm. The methods given for calculating the lengths of rafters, and for laying out and cutting them, are easy, accurate, and quick. Includes blue book of rafter length and roof construction explaining basic construction including rafter length tables. Swanson tool little blue book of instructions for roof and stairway layout. This means that for every 1m the rafter travels horizontally, the angled length of the roof will be 1.
It is used for setting out the heel cut birdsmouth. Determining roof rafter length conversion factors for roof rafters. The roof framers field manual blue palmetto home inspection. Includes markings for swanson 1number method of rafter layout, and is packaged with the swanson blue book of rafter length and roof construction and the speed clip to keep your square handy while you work. A series of tables giving the full length of all rafters for any span for 48 different pitches. Calculating rafter length starts with a few basic inputs that you will need to gather. How to use the swanson speed square as a framing square. The complete pocket reference to roof framing 2nd edition barry d. Measure from the plumb line shifted at the foot of the hip rafter using the hip rafter length to ridge dimension a. Usually on the houses i frame, they have an 8 on the main roof with a. The swanson speed square is our most popular product and remains the most trusted square of its kind.
Used by carpenters union apprenticeship programs from hawaii to new york. This means for every 12 of a common rafter in the same roof. Blackfilled gradations stand out against a matte finish for easy reading. Includes result for hipvalley factor, slope factor and. Irwin rafter square reference guide complete instruction book. We also have many ebooks and user guide is also related with swanson speed square blue book pdf, include. A modern handbook for roof framers by david mahin mcintire. Visit the roof framing page for more information on cutting roof rafters, and visit the roof pitch calculator for determining rafter lengths. All you need to know are the span of the building and the slope of the roof. Each page has a different table depending on the pitch angle of your roof with all the figures you need.
One length method by richard birch richard birchs method,one length method, that he developed from the swansons blue book. This line represents outside wall of the build ing. Cuts and bevels for common, hip, valley, jack, and purlin rafters. At an angle of 16 the total fall of the rafter is 680. Swanson tool company speed square with black markings at. Our roof rafter calculator tools are handy for calculating the number of rafters needed, rafter length calculator, lineal feet of rafter, board feed in ridge and subfacia,and the total board feet in the roof.
To get a visual idea of what the new overhang will look like, take a photo of the house from the side, make a photocopy, and sketch the desired extension at the same. Determining rafter length by rise and run by roninohio. How to lay out a hip rafter explained by a holly hill sc home. The little blue book for roof and stairway layout includes detailed instructions on how to use the speed square and big 12 speed square using the one number method sm for roof layout. Enter the value for the roof width outside to outside in feet, inches, and fraction, inches and fraction, or use the inches box to enter a value in decimals if that is your preference. Combines features of the framing, try, miter, and protractor squares. Once you know the length of the rafter, how do you correctly mark the angle. Rafter layout to lay out a rafter, you need to know the roof slope and calculate the rafter run roof slope is the incline of the roof, expressed as a ratio of the number of inches of rise vertical travel for every foot of run horizontal travel. A ready reckoner is pretty much a rafter length calculator a book full of tables for working out the rafter lengths quickly and easily. How to calculate the length of roof rafters captioned youtube. Swansons little blue book for roof and stairway layout. If you are making repairs to your roof or installing a completely new roof, you will need a rafter calculator to help you figure out rafter lengths. Use square to draw seat cut line from bottom edge of rafter to intersect building line.
In figure 186b, the second row in the table is headed length hip or valley per foot run. Sep 03, 2015 the above video shows one example of how to use a speed square for finding rafter pitches. Shiften or swansons blue book richard birch and i are having a discussion on shiften. Swanson little blue book of instructions for roof and stairway layout is useful for every roofer or carpenter. The most basic thing a roof cutter needs to know and understand is a rafter length is simply the hypotenuse of a right triangle, and the er is.
No need for special software that is special to one operating system or another. Along the measuring line, lay out and mark the length of the rafter. Sep 03, 20 shiften or swansons blue book richard birch and i are having a discussion on shiften. For atwelve inch cornice add to the main rafters l 4 1112 and. Allow for ridge thickness when determining rafter run to outer wall. I know the answer to tomcats question as i have a speed square with instructions. Deduct half the thickness of the ridge from the span length this length is the correct measurement from the top plumb line to the birdsmouth plumb line. This innovative gadget combines 5 tools into 1 a try square, a miter square, a protractor, a line scriber, and a saw guide. Adding the overhang onto the end of the rafters to fix the fascia boards to. To get overall plumb to plumb length add overhang horizontal length to horizontal span. How to calculate rafter lengths for gable, hip and valley. I learned how to lay out roofs with a framing square.
Made of heavygauge aerospace aluminum alloy, it is built to last. For larger roofs though, i use a roofing ready reckoner. Includes result for hipvalley factor, slope factor and the roof slope in degrees. Along the measuring line refer to page 8, lay out and mark the length on the rafter. The measuring line on a common rafter with an eave, is located along the side of rafter parallel to. Measure back 57 to form plumbcuts, giving rafter top length of 2466. My swanson speed square book will pretty much give all the lengths i need on the job. Become a faster, more accurate, and more efficient roof framer with the rafter book. Though, i did note that for the kindle fire needed you to download a free pdf reader.
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