Laying out an irregular valley rafter jlconline forums. Once you know the appropriate lengths, you will be able to determine the total cost of your roof project. Calculate the length of a rafter from the roof slope ratio of inches per foot, and a building width measurement. Our square has a handy 6 rule for quick measurements and scribing.
Our roof rafter calculator tools are handy for calculating the number of rafters needed, rafter length calculator, lineal feet of rafter, board feed. This slope and skew calculator makes it easy by performing all of the necessary trigonometry for each hanger condition in the roof. In this type of valley the main roof is framed and sheathed as usual and the intersecting roof is framed on top of the main roof. Instead, the author explains how to use an inexpensive handheld calculator to figure any common, hip, valley or jack rafter in seconds including rafters on irregular roofs and rafter pitches that aren. Easily move materials across solid or soft surfaces these carts are constantly in use in our shop. Layouts and degree settings are given for cuts that always give roof framers. Framing calculator diagrams hip valley roof sketches equivalent hawkindale angles irregular plan angle calculations irregular hip roof formulas common rafter and h. 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. Then the hip jack rafters tie into the hip rafter the same as the common rafters tie into the ridge. Speed the job of rafter or angle layout by using our rafter angle square. Hip and valley rafter sizing the building code forum. Jack rafters are sloping beams that are progressively shorter in length. You could also look in the wood frame construction manual wfcm.
Determining the slope and skew angles related to hip and valley beams can be a challenge made even more difficult when the roof slopes on each side if the hip or valley are different. I have always used wfcm, dont know how you can use the rafter span tables for hip valley sizing. Hip rafter drop for roof plane alignment equal pitched roofs only. The roof rafters provide integral structural support to the roof. The heel height, overhang, and ridge and fascia boards for both roofs will be the same. Take away the carpenters framing square, cmc calculator, and circular saw to show you what they really know about cutting rafters. Jack rafter purlin compound angles jack rafter angle calculations jack rafter difference in length hip valley sections calculator irregular valley length adjustment. First you need to calculate the hip rafter offset along the eave line. Use the calculator below to determine rafter length. Go to for this book s olc for a downloadable version of this graphic organizer.
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. Includes result for hip valley factor, slope factor and the roof angle in degrees. Blind valley rafters hidden valley rafters scotch valley rafters hip dormer gable dormer shed roof dormers. I taught stepping off with a square, reading from a rafter book and using a calculator. Roof framing book table of contents holy grail of roof framing. This menu option allows you to set the width of the hip rafter. 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. The full scale number will be the length of the rafter in inches for each foot of horizontal run distance. How to do rafters in metric commons, hipsvalleys and. I am a more recent visitor to your site and i have noticed the large number of questions about roof framing which has led me to believe that there seems to be a big gap in the knowlege of some roof framers.
These books will help you acquire the knowledge that has been. To get overall plumb to plumb length add overhang horizontal length to horizontal span. The string pinpointed the position of the valley rafter between the subridge and the rafter beam. A modern handbook for roof framers mcintire, david mahin on. Calculate the length of a rafter from roof pitch and a length measurement. Lay device on incline and hit start measuring to directly measure pitch. A rafter that runs from a hip rafter to a valley rafter, perpendicular to the roof ridge dormer rafter.
Hip and valley roof compound angle formulas and geometry before signing off for the weekend some thoughts on bridging the gap between geometry and formulas. The roof pitch calculator calculates slope, pitch, angle and rafter lengths, based on input of rise m and run r. Calculating common rafters with a construction calculator is fairly easy, but to be a master carpenter you need more roof framing angle information then the construction calculators offers. Simply use the drop down to enter the pitch of the main roof, the pitch of the complimentary roof, and the length of the long rafter to get reliable results. The diagram above depicts the crosssection of a typical prescriptive roof consisting of the rafters, a ridge board, ceiling joists and collar ties. 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. Jack rafter calculator works with different pitches. It can also be used for such things as decorative false gables or chimney crickets. Hip and valley roof compound angle formulas and geometry. Hip roof framing calculator with rafter angle cutting. How to calculate rafter lengths for gable, hip and valley. To calculate the length of a hip rafter, multiply the unit length by. The size of the ridge board and hip and valley rafters is prescribed as are the connections of these members. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter.
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. The hip rafter acts in the similar way to a ridge board. Framing square rafter table guide how to figure roof rise. 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. Hip rafter backing offset main perpendicular to hip rafter run line. I have never had anybody point to any table in the code book for hip and valley sizing. 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. Calculate the rafter, run, and rise in feet, inches, and fractions for all common rafter applications. From there i could calculate and cut the valley to length. Rafter is a sloping beam usually wood that supports a pitched roof. Hip valley line length ratio jack step down each rafter.
If youre framing a gable roof on a new house, or building a shed or even a doghouse with a gable roof, youll need to cut a number of roof rafters. A rafter that sits on top of the main roof without cutting into the main roof. With the rafter tools android app youll be able to. Valley rafter a nomath approach to valley plates whether youre tying in new gable dormers or adding a chimney cricket during roof framing, giving the valley jacks a place to land is an easy task with these stepbystep instructions. This quick demo briefly shows how to use this metric construction math power tool to do all your design, estimating and jobsite calculations far. Can they still layout and cut a hip rafter without the use of these tools.
Hip rafter backing offset adjacent perpendicular to hip rafter. The rafter tables on the standard framing square were developed at the turn of the last century and provide values to determine only 5 basic pieces of information. 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. Laying out an irregular valley rafter mike, you seem to have missed the point i was trying to make about calculators and roof framing. Roof pitch calculator calculates pitch, rafter length. This jack rafter calculator works in any situation every time. Click any image to enlarge it seems that most of the others used a rafter length book, or some sort of book reference, to. Rafter tools is an android app with functions to calculate complex roof framing angles that other roof framing calculators cant and dont offer. The valley rafter is not dropped but any rafters valley jacks which are nailed to the valley have to be raised the same amount as the drop so the top of the. Use the academic vocabulary glossary to look up their defi nitions if necessary.
The methods given for calculating the lengths of rafters, and for laying out and cutting them, are easy, accurate, and quick. Ordinarily a ridgetoplate valley rafter has a top plumb cut with single or double bevels, and a seat cut. Rafter tools is an android app with functions to calculate complex roof framing angles that other roof framing calculators dont offer. Use the diagrams on this page as a reference when inputting rise and run, and while interpreting the calculated results. The rafter tables allow you to calculate the length of a rafter by choosing a full scale number that matches the unit rise slope or angle of the roof. Visit the roof framing page for more information on cutting roof rafters, and visit the roof pitch calculator for determining rafter. For example, this rafter would be used when remodeling or adding on to an existing structure. The hip and valley factor is a number that is multiplied by the actual run horizontal distance of a common rafter to determine the length of a hip or valley rafter. This calculator helps you make the rafters of the suitable sizes required for your roofing. Blackfilled gradations stand out against a matte finish for easy reading. This means that for every 1m the rafter travels horizontally, the angled length of the roof will be 1. Press a letters on the picture and enter your size.
The important thing is that the sides of all the triangles remain proportional to one another. To determine the finished height of the ridge beam, add the rise. I found the builtin calcs very easy to learn and use. Calculating rafter length starts with a few basic inputs that you will need to gather. Deduct half the thickness of the ridge from the span length this length. Includes result for hip valley factor, slope factor and the roof slope in degrees. I usually just get the thousand yard stare when i call em.
Developed by carpenters and used around the world by master carpenters, contractors, builders and other construction pro s. For any questions, see the directions at the bottom. To calculate a blind valley roof select blind valley from the roof type dropdown list or select the corresponding button on the toolbar. With one number on our square you can frame a roof or a solar panel support, or layout stairs, cabinets, trim work, or many other construction projects. Improved methods for laying out and cutting hip and valley rafters are alone worth the price of the book. This discussion will explain how much to drop a hip rafter. These roof framing books were written to make complex roof framing simple rafter tools for android with quad tetrahedra analytic algorithm technology. Used and collectible books available now at great prices. What is the valley rafter slope angle for the dog leg valley. Valley roof the valley roof option is used to calculate valleys for 90 degree intersecting roofs with equal slopes and wall plates at the same height.