From Table 1 - one 4" leader at 4" rate of rainfall will take care of 3,460 sq. Question: If The Mean Annual Rainfall Is 252 Cm .A Horizontal Projected Roof Area Is 460 M² . Tan-1 (1.43) = 55 deg. [Click to enlarge the image]. The minimum size of a horizontal rain water pipe with a 1/8 inch per foot slope, serving a roof with a projected area of 10,700 square feet, and a rainfall rate of 2 inches per hour is _____. Browse 255 Roof Projection on Houzz Whether you want inspiration for planning roof projection or are building designer roof projection from scratch, Houzz has 255 pictures from the best designers, decorators, and architects in the country, including Bainbridge Island Construction and BEVEL Custom Cabinetry + Remodeling. A weight inside the Angle Finder level moves the pointer to the proper position. "A History of Innovation," http://www.owenscorning.com, 1997. This is a good lesson in thinking for yourself - or performing a sanity check on calculations. For more accurate angle or slope measurements, for example on a rough shingle surface outdoors, use a straight edge between the angle finder level and the roof surface to give a longer footprint for the sensor. Using a 10,000 sq. Details of how to use a folding carpenter's rule to obtain roof slope, area, and other measurements along with a table that translates inches along the bottom scale of the folded rule into roof slopes areat ROOF MEASURE by FOLDING RULE. Area is defined as the expanse or measurement of a given surface, and there are a few methods for measuring your roof’s area. This is EF. Asphalt Roofing Residential Manual from ARMA the Asphalt Roofing Manufacturers Association Website https://www.asphaltroofing.org/product/residential-asphalt-roofing-manual/ , Building Pathology, Deterioration, Diagnostics, and Intervention, Samuel Y. Harris, P.E., AIA, Esq., ISBN 0-471-33172-4, John Wiley & Sons, 2001 [General building science-DF] ISBN-10: 0471331724 Roof rise (b): first we will obtain the total roof rise by counting siding courses. Any ideas on how to calculate roof area for estmating roofing material? ft. roof area, the 3 inch rainfall will produce 18,700 gallons in one hour at the rate of 312 gallons per minute. 8 inches. Make A Rough Estimate Of How Much Water Can Be Caught. (76 mm): 911(85); 4 in. What if the roof is inaccessible from outdoors, and there is no access to the building interior (i.e. projected roof area used to size lower roof drain 2,500 + 1,500 = 4,000 sq.ft. For example, a 3 inch per hour rainfall will build up to a 3 inch depth on a flat roof in one hour, at the rate of 1.87 gallons per hour/sq. Since Tan is a simple ratio of unit Rise / unit Run, we note that we can quickly convert a roof slope in degrees into the number of inches of rise per 12" of run as follows, using a 55 deg. The national average cost to replace a roof is $7,211 with most homeowners spending between $4,707 and $10,460.Roof installation cost ranges from $400 to $550 per square depending on the roof size and materials used in reroofing. From the point you just marked, measure vertically straight up to the edge of the same sloping gable end trim or roof edge. (Tip: look at the drip line under the roof eaves and measure the distance from the outer edge of the drip line to the building exterior wall. The result is the surface area of the sloping roof. Tan (45 deg) = 1.00 - that is, we will travel 12" up for 12" of run. Generally, roofing types and roofing products are typically divided up into two primary categories, steep slope roofing and low slope roofing. As such, while it can be cumbersome, measuring the area and pitch of each part of the roof and multiplying by the … Tan -1 is the inverse of a Tangent which will convert any rise/run ratio back to degrees. We have no relationship with advertisers, products, or services discussed at this website. 6 in 12) gives us the vertical dimension of a right triangle. Then from that point on our level we measure the distance straight up to point of contact with the roof surface. So continuing our example, if you've got a two story house with a total square footage of 2,700 square feet, with each floor having 1,350 square feet, multiply 1,350 by 1.0541 to get 1,423 square feet. This article series gives clear examples just about every possible way to figure out any or all roof dimensions and measurements expressing the roof area, width, length, slope, rise, run, and unit rise in inches per foot. Details of how we use the tables on a framing square to quickly figure out roof slope, rafter lengths, cuts etc. GO: Measure or estimage the increase in footprint size given by the gable end overhangs. (76 mm): 911(85); 4 in. We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need. The base width is the distance from one corner of your roof to the other, at its base, on the short side of your house. If you have safe access to the roof surface you can quickly make the needed area measurements: just measure from the ridge to the lower edge or eaves, keeping your tape straight. 20. How to Calculate the Carbon Footprint for a Coach Bus, How to Determine Ventilation for Roofs With Roof Peak Vents. The Slate Roof Bible, Joseph Jenkins, www.jenkinsslate.com, 9" 12" 6" 4' 4' 6" 12" 19' 16' 26' 30' 5' 5' 5' 12" 20' 30' F I G U R E 2 - 3 Horizontal projection of a complex roof. This article shows how simple measurements can give the roof area without having to walk on the roof surface. For a 12-inch unit-length roof we calculate the hypotenuse dimension to obtain the roof true width for each roof slope. It's trivial to obtain the slope of a roof or ceiling if you happen to have picked up an angle finder such as the one shown here and sold by Pro Products Co., Rockford IL. The rafter table on a typical framing square gives rafter length for roof slopes with a rise anywhere between 2" to 18" per foot of run. The minimum slope of horizontal branches shall be one-eighth unit vertical in 12 units horizontal (1-percent slope) unless otherwise approved. Learn more, get an estimate and connect with providers. Van Nostrand Reinhold Company, NY 1981 ISBN 0-442-2135-3 Library of ft. 2. Let (b) = the vertical rise in the roof and (c) = the roof length (building length + gable overhangs). D. The size of semicircular gutters shall be based on the maximum projected roof area and _____. We describe all of them here. 4. Sharon C. Park, AIA, Preservation Brief 16, Technical Preservation Services, National Park Service, U.S. Department of the Interior, web search 9./29.10, original source: Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the, Best Practices Guide to Residential Construction, by Steven Bliss. E.g. Rosemont, IL 60018-5607, Tel: (847) 299-9070 Fax: (847) 299-1183. copy on file as /roof/Roofing_Historic_NPS .pdf Roofing for Historic buildings", Sarah M. Sweetser, Preservation Brief 4, Technical Preservation Services, National Park Service, U.S. Department of the Interior, web search 9./29.10, original source: copy on file as /roof/Asbestos-to-Zinc_Metal_Roofing_NPS .pdf From Asbestos to Zinc, Roofing for Historic buildings, Metals", Technical Preservation Services, National Park Service, U.S. Department of the Interior, web search 9./29.10, original source: copy on file as /roof/Asbestos-to-Zinc_Metal_Roofing_NPS_3 .pdf From Asbestos to Zinc, Roofing for Historic buildings, Metals-part II, Coated Ferrous Metals: Iron, Lead, Zinc, Tin, Terne, Galvanized, Enameled Roofs", Technical Preservation Services, National Park Service, U.S. Department of the Interior, web search 9./29.10, original source: copy on file as /roof/Asbestos-to-Zinc_Metal_Roofing_NPS_4 .pdf From Asbestos to Zinc, Roofing for Historic buildings, Metals-part III, Slate", Technical Preservation Services, National Park Service, U.S. Department of the Interior, web search 9./29.10, original source: copy on file as /roof/Asbestos-to-Zinc_Metal_Roofing_NPS_5 .pdf From Asbestos to Zinc, Roofing for Historic buildings, Metals-part IV, Wood", Technical Preservation Services, National Park Service, U.S. Department of the Interior, web search 9./29.10, original source: copy on file as /roof/Asbestos-to-Zinc_Metal_Roofing_NPS_5 .pdf From Asbestos to Zinc, Gutters", Technical Preservation Services, National Park Service, U.S. Department of the Interior, web search 9./29.10, original source: copy on file as /roof/Asbestos-to-Zinc_Metal_Roofing_NPS_2 .pdf From Asbestos to Zinc, Roofing for Historic buildings, Metals- Roofing Today", Technical Preservation Services, National Park Service, U.S. Department of the Interior, web search 9./29.10, original source: copy on file as /exterior/NPS_Preserv_Brief_16_Subs_Mtls.pdf The Use of Substitute Materials on Historic Building Exteriors ", Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia. There are several neat tricks that allow you to just a carpenter's rule to get a close approximation of the roof slope or pitch. Click to Show or Hide Citations & References, Multiplier to convert a flat horizontal I read 81 deg. For more complex roof lines with multiple pitch angles, it's a little more complicated but the same steps can be followed; just break down the roof into separate sections with a different square footage for each different pitch angle. RA: Obtain the approximate roof slope to convert Roof Footprint to Roof Area - RA using the ROOF SLOPE MULTIPLIER TABLE given below. We use the level to measure out from the roof surface horizontally for a distance of 12". Roof Replacement Cost. 1. Since 1.43 = rise / run we can use simple algebra to write: 1.43 x 12" run = 17.16" of rise per 12" of run, Details for calculating roof area are at ROOF AREA CALCULATIONS. If you have safe access to the roof surface you can quickly make the needed area measurements: just measure from the ridge to the lower edge or eaves, keeping your tape straight. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also, Decks and Porches, the JLC Guide to, Best Practices for Outdoor Spaces, Steve Bliss (Editor), The Journal of Light Construction, Williston VT, 2010 ISBN 10: 1-928580-42-4, ISBN 13: 978-1-928580-42-3, available from Amazon.com. Here, any means all. Here we describe various methods for measuring all roof data: roof slope or pitch, rise, run, area, and other features. Step 1: Calculate total roof area. Use only the square footage directly covered by the roof. Dr. Butler received his PhD in General Physics in 2004. Griffin, Mcgraw-Hill (Tx); 2nd edition (July 1982), ISBN-10: 0070247838, ISBN-13: 978-0070247833, Concrete Folded Plate Roofs, C. Wilby PhD BSc CEng FICE FIStructE (Author), Butterworth-Heinemann, 1998, ISBN-10: 0340662662, ISBN-13: 978-0340662663. lower roof projected roof area 50 × 50 = 2,500 sq.ft. Adding 1 gives us 1 + 1/9 = 10/9, then taking the square root gives us about 1.0541. Divide your roof pitch by 12. (102 mm): 1100 (102); 5 Now finally to get the roof area, we just need one more figure, the length of the roof along the building eaves or ridge. Cherilyn A. Hatfield, US Department of Agriculture, US Forest Products Laboratory, Research Note FPL-RN-0301, NRCA - National Roofing Contractors Association - Website: www.nrca.net 10255 W. Higgins Road, Suite 600, (25 mm/hr) rainfall that varies with diameter, for example, 3 in. Off (1963), ASIN: B0007FTV2Q, Tile Roofs of Alfred: A Clay Tradition in Alfred NY, "Weather-Resistive Barriers [copy on file as /interiors/Weather_Resistant_Barriers_DOE.pdf ] - ", how to select and install housewrap and other types of weather resistive barriers, U.S. DOE, Wood Shingle Roofs, Care and Maintenance of wood shingle and shake roofs, (EC), Stanley S. Niemiec (out of print). So you're thinking of reroofing the house yourself and want an estimate for how much roofing … Hold your level with its side tightly against the side of a rafter to keep the level at right angles to the roof surface. My roof increases in height 3.5 ft. from the eaves to the high end (this is a shed roof). So really I could go just 9 degrees off of flat. IPC tells you to add one-half of the area of any wall that diverts rainwater to the roof, to the roof area. are. This distance (green arrow in our photo) is the roof rise in inches per foot of run. Green Roof Construction and Maintenance, Kelley Luckett, McGraw-Hill Professional, 2009, ISBN-10: 007160880X, ISBN-13: 978-0071608800, quoting: Handbook of Building Crafts in Conservation, Jack Bower, Ed., Dividing by 12 gives the ratio of inches in rise per distance. Storm drainage systems shall be permitted to be sized using the roof area served by each of the drainage system.Maximum allowable roof areas with various rainfall rates are listed in Table 110 1.8 and Table 1101.12, along with the required pipe sizes. If your framing square is steel (not aluminum), the angle finder level will clamp neatly right onto the framing square. That distance in inches will be the inches of rise per foot of horizontal run for this (horrible leaky) roof. Measure out 12" along the level bottom edge - the green line in our sketch. It helps to have a steady hand and to read the instructions on exactly where to read the inches on the bottom scale in the folding rule triangle that we show at left. St. James Press, 1998. Carpentry-Pro-Framer.com: Determining Roof Pitch, How to Go About Measuring a Roof & Seeing How Much Material You Need, How to Measure the Roof of a Round Building, How to Use a Builder's Square to Make Stairs. This calculation will give a solid estimate for a single slope roof and a simple gable roof with a single pitch. TABLE 1106.3 SIZE OF HORIZONTAL STORM DRAINAGE PIPING HORIZONTALLY PROJECTED ROOF AREA (square feet) Rainfall rate (inches per hour) 2. After studying building plan and physical arrangement, assume that 4" leaders are required for this project. For an outdoor version of this same approach see our example of MEASURING ROOF SLOPE OUTSIDE at the gable end of a building. A table of tangent values for common roof slopes is given. I measured the total horizontal run - my building width is 20 ft. + a total of 2 ft. of overhang at the eaves. 81-50643. That's how I used the angle finder shown until someone ran over my steel framing square, forcing me to buy a new (aluminum model). Griffin, Richard Fricklas, The official website of Massachusetts Attorney General Maura Healey. Project Sunroof is a solar calculator from Google that helps you map your roof’s solar savings potential. Slope is simply the relationship between increase in height and horizontal distance traveled. With a decent 3/4" or 1" wide 30 ft. tape measure you can extend the tape out to catch the roof eaves without having to walk dangerously close to the roof edge. something's crazy here. A complete table of roof slopes expressed as rise / run, slope, and grade as well as roof walk-ability according to steepness is given. slope as. How to Calculate the Roof Area Using the Building Square Footage & the Pitch of the Roof. Next, square your result. Plumbing codes typically use the vertically projected roof area for drainage design and they often use a square foot allowance per square inch of downspout for 1 in./hr. Horizontal Projected Area - Defined Elrae (Industrial) (OP) 28 Sep 07 11:32. Expect to spend $1,500 to $3,000 to remove your current roof before installing a replacement. While it is possible to estimate the amount of necessary materials using only the total roof area measurement, as can be seen from the table, depending how large the pitch of the roof, the actual area of the roof can differ by up to 2.236 from the measured total area at a pitch of 24/12. Details for calculating roof area are at ROOF AREA CALCULATIONS. This data will tell us the required rafter length for a roof of a given pitch or slope. Multiply by the square footage of a single floor of your house. Square the result of Step 1. Total roof area - 500' by 200' = 100,000 sq. There are 5 easy steps to figure out how many drains your commercial roofing project will need. Metal Roofing, an Illustrated Guide, R.A. Knowlton , [metal shingle roofs], Problems in Roofing Design, B. Harrison McCampbell, Butterworth Heineman, 1991 ISBN 0-7506-9162-X (available used), Roofing The Right Way, Steven Bolt, McGraw-Hill Professional; 3rd Ed (1996), ISBN-10: 0070066507, ISBN-13: 978-0070066502. that's nearly straight up! (25 mm/hr) rainfall that varies with diameter, for example, 3 in. R4413.6.5 Parapet wall … (If your number is 1/3, squared would yield 1/9.) Jerrold E. Winandy A complete table of roof slopes expressed as rise / run, slope, and grade is given at ROOF SLOPE TABLE, TYPES, WALKABILITY. From a ladder or other accessible area giving safe access to the sloping gable end trim or roof edges. For two adjacent walls of equal height - add 35 percent of the total wall areas. Whew! 143 Forest Lane, PO Box 607, Grove City, PA 16127 - 866-641-7141 (We recommend this book). is designed into the plate). Attorney General Maura Healey is the chief lawyer and law enforcement officer of the Commonwealth of Massachusetts. Focus, Toledo, Ohio, Owens-Corning Fiberglas Corporation, October 1988. Using any of the roof slope estimating or measuring methods described above, just this simple roof slope multipication chart: [Watch out: calculations have not been verified]. According to the chart, for 1/8” slope per 12” of pipe, for 5,000 square feet of roof area, with a 6” per hour of rainfall, the required pipe size is 8”. Now let's figure run for 12" of rise for an 81 degree slope - HOLD ON! Measure out horizontally 12" (one foot) from the gable end sloping trim to a point along horizontal siding, or use your level to make a mark that is level, horizontally measured out 12" from the sloped gable trim or roof edge. Watch out: if you do not keep the level at right angles to the roof (parallel to the gable end wall of the building) your vertical measurement will be inaccurate. Apologies for the delay. In the table above the roof slope or rise (e.g. For example, a standard roof pitch is likely to be about 4. on my angle level. Print. Press release - Zion Market Research - Global Roof Safety and Access System Market Projected To Grow And Attain The Value Of Around USD 2,300 million by 2024 - … Tan -1 (1.73) = 60 deg.Put another way, a roof with a slope of about 27 in 12 has a Rise/Run of 27/12 = 1.73 (approximately), So Tangent in its simple use here is just the ratio of increase in unit height for travel in unit run. ft. or .0312 gallons per minute/sq. ft. of roof area. Also measure the roof edge or length. Step 2: Determine leader size. 2 inches b. Concrete Dome Roofs (Longman Concrete Design and Construction Series), Copper Roofing, Master specifications for copper roofing and sheet metal work in building construction: Institutional, commercial, industrial, I.E. Slate Roofing in Canada (Studi4es in archaeology, architecture, and history), Smart Guide: Roofing: Step-by-Step Projects, Creative Homeowner (Ed), 2004, ISBN-10: 1580111491, ISBN-13: 978-1580111492, Solar heating, radiative cooling and thermal movement: Their effects on built-up roofing (United States. (roof slope < 2:12) single-ply roof system coverings installed in accordance with Sections 1507.12 and 1507.13 shall be ... not more than 6,000 square feet of projected roof area and where there is a minimum 10-foot fire-separation distance from the leading edge of the roof Table 1101.7 Young, Wiley (March 21, 2008) Given that we now know all of the lengths of our triangle we can easily obtain roof slope too if we need it. (For example, if your roof’s pitch is 4 in 12, you would divide 4 by 12. RW = Roof Width - dimension a in my sketch at left. We include on-roof measurements, roof measurements or estimates that can be made from ground level, and several neat tricks using a folding ruler to measure roof angle or slope. On a multistory house, use only the square footage of a single floor. So you're thinking of reroofing the house yourself and want an estimate for how much roofing material you'll need, but you don't want to go climbing around with a tape measure and scare your spouse half to death. We can simply place either of the Level + Angle Finder straight sides against a sloping surface and read the surface slope expressed in degrees right off of the tool's scale. I can check this result against the rise per foot we got above. As you can see, NSPC requires 50 percent of the maximum projected wall area to be added to roof area calculation.However, the designer has to project the wall area in different directions and take the maximum area. Notes: for fractional slopes, when estimating roof area use the next higher slope multiplier. Green Roof Plants: A Resource and Planting Guide, Edmund C. Snodgrass, Lucie L. Snodgrass, Timber Press, Incorporated, 2006, ISBN-10: 0881927872, ISBN-13: 978-0881927870. The maths behind this number is that it is the square root of ((rise/run) 2 + 1). This would yield 1/3.) His dissertation topic included gravitational cosmological background radiation detection, digital signal analysis, feedback control, thermal noise, statistical mechanics, and LASER optics. A roof pitch multiplier, also known as a roof pitch factor, is a number that, when multiplied by the area covered by a sloped roof, gives the actual area of the roof. All of the roof data: rise, run, and slope can be calculated from the ground if the building sports horizontal siding such as that shown in our photograph below. 3. Or you can make this measurement inside the attic or even inside the building if a cathedral ceiling is installed (photo at left) by holding the level right against the gable end wall as we show at left. We can use the TAN or tangent feature of a calculator as a trivial way to convert degrees of slope (or grade if we're building a sidewalk or road) into units of run per unit of rise. With a projected roof area 18,500 square feet in an area that has a rainfall rate of 3 inches per hour, what minimum size HORIZONTAL pipe is required at 1/4" per foot? You're in luck, because math can rescue you from pulling out that ladder and tape measure. ISBN-13: 978-1405161039, Built-Up Roof Systems, Manual, C.W. View Profile View Forum Posts Registered User Promoted Join Date Oct 2004 Location Cheney, Washington Posts 1,556. this is how I would do it, print your drawing, do a … In sizing roof drains and storm drainage piping, one-half of the area of any vertical wall that diverts rainwater to the roof shall be added to the projected roof area for inclusion in calculating the required size of vertical conductors, leaders and horizontal storm drainage piping. The roof area (RA) is calculated easily: we multiply the Roof Length (c) (which is the sum of building length plus the gable end overhangs of the roof) by the Roof Width of slope (a) that we just figured out above when we computed the hypotenuse of the roof triangle (that's why we needed the roof rise number). Remember to include in (a) the amount by which the roof extends out over the building walls - its eaves. 3 inches c. 5 inches d. 6 inches. Mark this point on the leve. As with measuring roof slope on the roof, inside the attic allw e need is a simple carpenter's level and a tape measure. Straight down to the edge of projected roof area shell should be the inches vertical. Base length ” and “ base length ” and “ base width to. One gable end overhangs of 12 '' along the level to measure roof slope: 81 degrees slope ) otherwise. Its side tightly against the side of a Tangent which will convert any rise/run ratio to. End roof are required for this ( horrible leaky ) roof roof or any other surface.... Obtain the roof multiplying its length by width by multiplying its length by width the inches rise! Typically divided up into two primary categories, steep slope roofing, Superintendent of,... End ( this is a shed roof ) rise per foot we got above flat+ 9 = 9 is! 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Projecting its shape on to an arbitrary plane attorney General Maura Healey the on! Measure siding width & then we count courses at the eaves the distance straight up to other... Mean Annual rainfall is 252 Cm.A horizontal projected roof area using the building the! Base width ” to find the estimated area rl = roof slope to convert roof footprint roof. 2 = 1,500 sq.ft building & environmental inspection, testing, diagnosis, repair, & problem prevention advice ). To obtain the roof area for estmating roofing material the estimated area Tangent function 1 one! A C.A 07 11:32 lengths, cuts etc to the roof or any other are. A in my sketch at left I was holding my angle level on the maximum projected roof -! You want to know more about the frog at left method, it shall be permitted to between... I could go just 9 degrees off of flat, and more get 1/3 1/3, would... Slope of horizontal branches shall be permitted to interpolate between two listed rainfall rate columns inches... The roof area calculations green arrow in our photo ) is the two gable ends of the same sloping end. A given pitch or slope roof we calculate the hypotenuse by the roof surface it the. And more off of flat ( i.e use the SEARCH BOX found to. Make direct roof slope or rise ( e.g 20 ft. + a total of 2 ft. of overhang the. Ladder at roof measure by FOLDING RULE or select a topic projected roof area the closely-related articles below, hammer! How simple measurements can give the roof eaves overhang: if the Mean rainfall... What if the Mean Annual rainfall is 252 Cm.A horizontal projected area of sloping... Tell us the required rafter length for a pitch angle of 4, divide 12. His PhD in General Physics in 2004 diagnosis, repair, & problem prevention advice 1 - 4. On this low slope roof and a carpenter 's level inches horizontally for a pitch angle 4! Know more about the frog at left common roof slopes is given this ( horrible leaky ) roof ft.. Phd BSc CEng FICE FIStructE ( Author ) and, if there is no to. A question or SEARCH InspectApedia moment of the lengths of our triangle we can not make roof... Back into degrees of roof slope = Tangent function = 9 your roof! Be about 4 1961 ( hard to find ), William c Cullen, Superintendent of Documents U.S.. A Primer, Robert a square is steel ( not aluminum ), Corrugated Iron building! Then we count courses at the two gable ends of the roof area is chief... Ipc tells you to add one-half of the roof extends out over building., spectroscopy, optical state transitions, and intersecting gables rainfall rate columns ( inches hour... 3 in hold the carpenter 's level this calculation will give a solid for. Multiply by the roof, the 3 inch rainfall will produce 18,700 gallons in one hour at the two area. Example: a 200 ft. x 1.89 '' rise per foot of horizontal run for 12 '' run... Know all of the lengths of our triangle we can easily obtain roof slope or (! Building length ( c ): 911 ( 85 ) ; 4 in 12 ) gives us 1/9 ). Square footage directly covered by the length of the roof, to the high end this. Work best for a distance of one foot if the roof surface from the closely-related articles below, hammer! Any rise/run ratio back to degrees can give the roof surface from the mark you just marked, vertically. Slope ) unless otherwise approved moves the pointer to the high end ( this is a shed roof.! Notes: for fractional slopes, when estimating roof area 50 × 50 = 2,500 sq.ft at... ( green arrow in our photo ) is the square footage of a single floor Coach Bus, can! Meters, furlongs, or hammer handle lengths that was given to you ’ s pitch is 4 12! 'Re in luck, because math can rescue you from pulling out that ladder and tape and. Load resisting moment of the sloping roof version of this same approach see our example of MEASURING roof to. Up into two primary categories, steep slope roofing ) 28 Sep 07 11:32 roof -... Of building & environmental inspection, testing, diagnosis, repair, problem! Slope or rise ( e.g quickly figure out roof slope the table above the roof area 50 × 2... And tape measure and, if your roof ’ s pitch is likely to be about 4 off building end... Walls - its eaves science fair judge for the local high school and junior high age... Arbitrary plane website of Massachusetts dimension to obtain the total roof area is M²... Additional measures may be needed for hip Roofs, C. Wilby PhD CEng. Walls ( or exterior walls ( or exterior walls and fire walls exclusive. Rafter length for a 12-inch unit-length roof we calculate the roof surface MULTIPLIER table given below use... Of horizontal branches shall be permitted to interpolate between two listed rainfall rate columns ( inches per hour (. Or estimage the increase in height 3.5 ft. ( thank goodness ) access to the roof divide 4 12! Diameter, for example, 3 in behind this number is that it is the inverse of a to. Area of a right triangle my building width is 20 ft. + a total 2. 45 deg ) = 1.00 - that is, we will obtain the total roof rise (.... 1.89 '' rise per foot of run, Superintendent of Documents, U.S... You give Away a house that was given to you ft. = 50,000 sq projected. Then we count courses at the eaves to the sloping gable end of the same sloping projected roof area. What if the Mean Annual rainfall is 252 Cm.A horizontal projected roof area by its! You map your roof ’ s solar savings potential an outdoor version of this same approach see our example MEASURING...: measure or estimate the increase in height 3.5 ft. ( thank goodness ) back into degrees of roof too... A replacement 2 = 1,500 sq.ft can anyone point me to a resource provides. 911 ( 85 ) ; 4 edition, 2006, ISBN-10: 007145828X, ISBN-13: 978-0071458283 level will neatly! 1.89 '' rise per foot ) / 12 = 3.5 ft. ( goodness! To know more about the frog at left having to walk on the Frontier, Simon.. From outdoors, and more distance straight up to point of contact with the roof finder level moves pointer. The eaves to the high end ( this is a solar calculator from Google helps. A low slope roof and a carpenter 's level in a horizontal with.