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How to calculate roof pitch height

Roof Pitch Calculator - Calculates Pitch, Rafter Length

• e the finished height of the ridge beam, add the Rise (M) and the Y height. To deter
• The roof pitch is the slope of the rafter. The pitch is commonly defined as the ratio of rise over run in the form of x/12. The rise is the height of the roof, and the run is the horizontal span (as pictured above). For example, if a roof has a pitch of 4/12, then for every 12 inches the building extends horizontally, it rises 4 inches
• der, please, don't forget to add height of rafter, thickness of roofing material and ridge vent to the number that you'll get using our calculator. If your goal is to only calculate the roof height, do not enter any numbers in Wall Height field and only use Building Width and Roof Pitch fields
• If you do need to calculate the pitch, an estimate or shortcut is usually more practical than measuring the roof's overall dimensions. Here are a couple examples: For a simple gable roof, the span (wall to wall) will be twice the size of the run (wall to ridge, horizontally). Divide the slope by two to get the pitch
• pitch = tan (angle), where angle is the roof pitch expressed in degrees. If you want to find the roof pitch in the form of x:12, simply calculate the pitch and substitute 12 for the run length. The value displayed as the rise will be your x. Roof slope calculator - example of us

10-12. 39.81°. 11-12. 42.51°. 12-12. 45°. This is our pitch calculator which will convert pitch to angle or angle to pitch for half degree roof slope calculations. Enter any pitch or fraction of pitch to find angle. Enter any angle or fraction of angle to find pitch Formula to calculate roof pitch height. Since the rafter, the rise/height and the run of a roof form a triangle, we can use the Pythagorean theorem to find the roof pitch height provided your given the length of the rafter and the length of the run

ROOF PITCH CALCULATOR [How to Find the Pitch of Your Roof

• How do you calculate a roof pitch? Roof pitch refers to the slope which the rafter creates. You can assess this in two ways, either as the roof pitch angles which the rafters make with the horizontal or the proportion between the run and the rise of the roof
• The length of a slope is calculated using the Pythagorean Theorem. This theorem is done by multiplying the square's square root by the sum of the squared width and the squared height. So: Square root ((width x width) + (height x height)) = Slope length An inclination of 100
• Roof slope, pitch, rise, run, area calculation methods: here we explain and include examples of simple calculations and also examples of using the Tangent function to tell us the roof slope or angle, the rise and run of a roof, the distance under the ridge to the attic floor, and how wide we can build an attic room and still have decent head-room

Roof pitch is the measurement of a roof's vertical rise divided by its horizontal run. It is often compared to slope, but is not exactly the same. In the United States, a run of 12 inches (1 foot) is used, and pitch is measured as the rise of the roof over 12 inches One method to find the pitch is to climb on the roof and measure the rise for a 12″ run. You'll need a level that is 12″ or longer and a tape measure. On the roof, hold the level perfectly level, and measure the height from the roof to the level 12 inches away from where the level touches the surface; this will be the rise Roof pitch calculator degrees. Roof pitch calculator degrees help you to convert pitch ratio or fraction of slope in degrees in following two steps:- 1) divide the first part of the ratio by 12 to figure out the pitch and 2) find the inverse tangent of pitch to find the angle in degrees. For 2/12 roof pitch into degrees: - 1) pitch = rise/run.

In order to get a handle on how much building materials you need and the associated cost, it is worthwhile figuring out some additional quantities such as rafter length and surface area. The roof pitch chart can help. Example 1: Calculating rafter length using the roof pitch chart. Decide what roof pitch is most appropriate for your building If your roof pitch is greater than 3 your roof is considered pitched. Read more about roof pitch at Wikipedia. This free roof pitch calculator will take your roof width (see the picture) and rise (the height of the roof) and will calculate the roof pitch both as numeric value and as a degree Shed Roof Pitch Calculator. Knowing how to calculate roof pitch, rise, run, and ridge board height is essential to any shed construction. A roof pitch calculator can make things much easier. Simply plug in the values of your roof and it will show you slope percentage, degree, and even length

Calculate the height of your roofing surface using the width and pitch. For example, if your roof is 20 feet wide and has a pitch of 1/2 (which means it rises 6 inches in height for every 1 foot of width), the height of your roofing surface from base to peak is 10 feet To calculate your pitch and size, measure your roof and plug in your measurements in accordance with the diagram below. Enter EITHER Roof Rise or Roof Pitch. 2) Pitch to Angle (Degrees) Calculator Enter pitch in the first box - calculation is automatic By calculating the slope of a roof, it is possible to determine the height of the ridge, the length of the pendulum, and the coverage area. In addition, this information helps to define the number of tiles to be used in the work, avoiding the waste of materials

Building Ridge Height Calculato

Gable (Rake) Wall Framing - Wall Height Calculate the height of a gable (rake) wall based on roof slope and half of the wall's horizontal length the rake run The calculation takes into account two main indicators: So pitch of roof is equal to = rise/run = 6/12. Depending on your roof slope add 4 to 5 inches for heel height. 2) pitch to angle (degrees) calculator. The rise is the height of the roof, and the run is the horizontal span (as pictured above). Pitch = rise / run = 1.5 / 6 = 25%

Use the roof pitch to find the height of a roof peak. The pitch of a roof determines the height of the ridge board that runs the length of the house. Carpenters measure roof pitch as inches of rise per 12-inches of run. A 1-in-12 roof pitch roof rises 1 inch for every 12 inches of run Keep this in mind as you are calculating the rafter length. The pitch (highest point) of the roof is an important ratio when measuring the truss. A sample calculation would be: A roof that rises 1 inch for every 4 inches of its horizontal distance has a 1/4th pitch. The best outcome of the pitch depends on the covering of the roof My website with everything: http://bit.ly/craftmathMainPagePrivate Tutoring: http://bit.ly/privateTutoringTutorial Video Request: http://bit.ly/requestAtu.. Height Calculation for a Common Truss. Calculate the height of a common truss using the building width and the slope of the roof. If you can't get the heel height, most residential trusses will have a 3 ½ top cord. Depending on your roof slope add 4 to 5 inches for heel height Directly Measure Roof Pitch Angle and Calculate Pitch and Angle on Phone or Tablet. Set Bevel Gauge directly from phone or tablet screen. Roof Angles and Rafter Plumb-Cuts. Visit this page on your Phone to directly measure pitch and angles. With a mobile device, a button will appear

A description of what pitch is and how to manipulate the numbers when framing and planning a project. Carpentry is mostly breaking down the elements of a bui.. To calculate the pitch of a particular section of the roof, you need to picture that section of roof as a right-angled triangle. A right-angled triangle is made up of three sides: the opposite side, the adjacent side and the hypotenuse. The slope of the roof (which is diagonally across from the 90° angle) is the hypotenuse of the triangle For example a 3 pitch or 3 in 12 pitch or 3/12 pitch, all mean that the roof rises 3 inches, for every 12 inches of it's horizontal run. Using pitch, its footprint, and basic geometry, you can quickly and with a high degree of accuracy calculate the length of the gable sides The slope of your roof, or pitch, is done by how many inches it rises for every foot of horizontal distance. So, if the roof rises 3 inches while it runs 12 inches, that will be considered a 3-in-12 pitch, a fairly flat roof, but easy to walk on. As the first number goes up, like 4-in-12 pitch, or 6-in-12 pitch, the roof gets steeper and steeper The roof pitch is a measure of roof steepness. The pitch is defined as the slope of the roof, and is commonly represented as the ratio of the RISE over the RUN in the form x/12.. The rise is the height of the roof at its highest point, and the run is the horizontal span of the roof, measured from the roof ridge to the side of the building.. As an equation

3 Ways to Calculate Roof Pitch - wikiHo

To calculate the angle of slope of the roof we should know this simple formula: the height of the roof ridge is divided into half the length of the pediment. The height of the ridge is calculated in the following way: It designs the width of the span. The width of the span is divided into two. The resulting value is multiplied by an individual. How Roof Pitch is Calculated. To accurately calculate the area of your roof, you must first determine its slope, or pitch. A roof's pitch is determined by how much it rises vertically for every foot it runs horizontally. Thus, a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs The roof pitch would be described as a 6:12 pitch. The primary reason roof pitch exists in the first place is to redirect water. It is an essential element to ensure water drains properly off of your roof. The pitch of your roof also helps determine the type of materials that can be used on your roofing system Wall height calculation for the mono pitch roof [closed] Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Mathematics Stack Exchange. Closed 3 years ago. I am trying to find out the height of the wall for my poly-tunnel construction This height above plate rafter script - calculator will return the H.A.P. for different sizes of rafters with equal pitchs. The script also returns passed or failed for the D/4 and 1/3 rule for rafter bearing above the plate line. HAP rafter table for all material sizes and pitches

If you are thinking of a building project that involves a gambrel roof design, here are a few tips to help you calculate the angles. Four Angles Needed. With the gambrel roof design, there are four angles that are used to make up a total of 180 degrees. Depending on the size of the roof, and the pitch of the roof, these angles will change It is just simple geometry. For instance, a 24 foot truss with a 12/12 roof pitch would have a height of 12'. A 6/12 roof pitch would have a height if 6' 12/12 means there is a 12 rise for a 12 run. 6/12 is a 6 rise for a 12 run. Cheers, Dou How to calculate length of roof rafters. Let us now discuss some common terms are used in figure out length of roof rafters. 1) Rafters of roof:- distance between the top ridge on roof or hip of the roof to the wall plate of external wall. 2) span of roof :-span of roof is the clear distance between the two supporting arc,beam, external brick wall or beam truss

Roof Pitch Calculato

Measuring the Pitch. To calculate the area of your roof, first you'll need to calculate the pitch of it: First, use your measuring tape to measure 12 inches on your large level and make a mark at the 12-inch line. Next, place your ladder against your house at the gable end. Climb to the top of your roof Commonly, the pitch is known as the slope (incline) of the roof. Roof pitch can also be defined as the vertical rise divided by its horizontal span (or run). In construction, the roof pitch can be known as stair while in trigonometry it is known as the tangent function. Pitch is expressed as a degree or percentage in countries that use the.

Roof Pitch Calculator Pitches To Angle Char

Roof pitch angle calculator - briefly about the calculation. The roof pitch angle calculator is used to calculate both the roof slope angle and the missing roof data — the projection, height, length, and slope angle of the roof. Visually, where and what values can be seen in the drawing of the calculator, which is under the form of calculation This roof shingle calculator requires four basic inputs: Roof length (measured in feet) Roof width (measured in feet) Roof pitch. Roof type (either gable or hip) Using these four inputs, you will get several basic outputs: Roof area (measured in sq ft) Number of squares. Number of bundles Here's an example of how to calculate the height of a common shaped pitched roof truss. An approximate height of a pitched truss can be calculated with the following formula: take 1/2 the span and multiple it by the pitch. Then add about 4 in. for the top chord lumber. For example: a 33-9-0 (33 ft., 9 in. and zero 16ths) truss on a 4/12 pitch. A 4/12 roof pitch is referred to as the roof rises 4 inches in height for every 12 inches, as it measured horizontally from the edge of the roof to the centerline. The gentle slope of a 4/12 roof pitch falls on the cusp between moderate-pitch and low-pitch Determining the Ridge Beam Height. If you know the slope (X in 12) you want to use for your roof framing design, you can use it, along with the run (R), to determine the height of the ridge beam.For example, if the slope is 4 in 12, and the run is 12 feet, the ridge beam height (M) will be 4 feet. The finished ridge beam height (Z) above the top of the wall will be (M) plus the Y Height Knowing that will determine what your roof's pitch since the run is 12 inches by default. In the attic, put the level against a rafter with the 12-inch mark on the bottom. Measure the inches from the level's end up to the bottom edge of the rafter. That measurement is the roof's rise

The roof pitch prevents water from pooling on the surface of the roof, greatly reducing the risk of roof leaks. Formula to calculate roof pitch in degrees. If you have the run and the rise, all you need to do is; Example: Suppose your run is 8 feet and your rise is 6 feet, calculate your roof pitch in degrees.. In roof pitch calculator, pitch value can be obtained by dividing N by 12 and divide S by the answer. To find slope divide rise by run and multiply it by 100 and for angle take tan -1 of S/N. Calculator. Formula. The rise is the distance from the top of the roof to the bottom. The run is the distance from the outside of the wall to the inside.

How to Calculate Roof Pitch Height

1. consistency with any height limit imposed by a land use permit or SEPA environmental review. Height, Building—(either) Definition 1: The vertical distance from the lowest existing grade at the wall of the building to the highest point of the coping of a flat roof or to the average height of the highest gable of a pitch or hip roof
2. ed by calculating the rise versus the run or elevation slope of the roof. This measurement can be taken from inside your attic (the safest way) or you can climb on the roof to make the deter
3. There is also the matter of roof pitch. So, when it comes to cutting studs (also known as joists or rafters) for your roof, you have to calculate pitch. When you know the pitch, you can cut the proper length and angle for your joist to build the roof. First and foremost, though, we need to know how to measure the pitch of a roof
4. Calculate the total surface area of the roof using the following formula: pi times the radius times the rafter length, also called the slant height. To find the surface area using the diameter in.
5. e what roof pitch is, how to calculate a roof's pitch, and what the
6. How to measure post height. Diagram shows how to figure post height, by adding attachment height with your grade slope and then subracting your beam height and pitch you will know what the post height is. A is the distance from the bottom of the hanger to the ground, B is the amount of fall your ground or concrete slab has going away from.
7. You'll also need to look for a hip roof design calculator to let you work out the height and the overall format of the design, ensuring that your calculations are going to allow for the type of design that you were hoping for in the first place. After that, you will have to try and find a good hip roof pitch calculator to make sure you can.

Roof Pitch Calculator (Roof Slope Calculator) - [100% Free

1. 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 sub-facia,and the total board feet in the roof. Rise and Run means that a 6/12 pitch roof has 6 of rise (vertical) for each foot of run (horizontal). Roof Pitch Calculator
2. e the length of roof for your sloping side. The calculator has calculated the roof length to be 4.22 ft (see the image above). This means your roof size is 4.22 ft by 8 ft. (Remember, the coop is 4 ft by 8 ft—this is where the 8 comes from.) Step 4: Add on the length of the overhang
3. e Roof Pitch To deter
4. In the chart above, figures in red indicate peak height measurements for 10′ to 30′ buildings with this standard 3/12 pitch. Since Absolute Steel designs and manufactures its own steel building frames, we are able to offer you roof slopes of a different pitch, if needed for your particular application. Extra charges may apply
5. Taking ½ of the building width (16 feet) x the slope 8/12 gives us a rise in the center of 128 inches (or 10'8). Adding the 10'8 to the eave height of 12' makes the overall building height 22'8 (or 22.67'). The mean roof height would be the average of 12' plus 22.67' or 17.33' as shown on the building plans
6. The pitch of a roof is nothing more than a ratio that indicates how much rise there is in the roof over a 12-unit horizontal distance. Example: Ratio of 5:12 or 5/12 When you see the ratio 5:12, this means that for every 12 horizontal feet, the roof changes 5 feet in vertical height
7. e the width of a cupola's base, the general rule of thumb is a  Calculate a slope, a gradient, a tilt or a pitc

Skillion roof framing calculator plan diagram with full dimensions. Walls (building) 10000 x 4000. Roof Angle 15°. Lower overhang 400. Upper overhang 400. Roof 10000 x 4969. Roof Angle 15° The angle will be the roof pitch The opposite site is the rise of the roof The adjacent side is the rafter run The hypotenuse is the true length of the rafter. The example shows brick veneer construction (see Figure 1) the roof pitch is 20°, the rafter run is 3.340 metre s and for an eaves width of 0.6 metres, the actual measurement to calculate the overhang is in this case 0.76 metres (0.60.

Then, calculate the pitch of the roof by placing a level against it, angling the level so the bubble is centered, and measuring the distance between the end of the level and the roof. Next, use the pitch to look up the pitch multiplier for the roof online. Finally, multiply the area by the pitch multiplier to determine the roof's square footage Finding the best angle for your greenhouse roof is not as clear cut as some solar greenhouse designers make it sound. Solar greenhouse designers often cite this rule of thumb: To find the best angle (or pitch) for a greenhouse roof take your latitude and add 20 degrees. While the logic behind this rule is sound, it is a dramatic oversimplification that can lead to costly and unnecessary. Calculate the length of common rafters with this free and easy online tool by entering a dimension for the roof width, selecting a pitch for the roof, and the thickness of the ridge. The results are automatically fired. They include : The length of the rafter. The rise of the rafter. The run of the rafter. Height of the scaffold

The chart below will enable you to calculate the center height of your building. For example, if the carport or garage is a Standard Style Double unit, 20 feet wide with 7 feet legs, add 3′ 0″ to the 7 feet leg height for a total height of 10′. This height is measured at the very bottom of the frame under the roof panel Kalk.pro is online shed roof calculator (single slope, pent roof, skillion) - program determines basic material consumption for roof building, roofing underlayment volume, all quantitative and dimensional values of the shed pent roof truss system:. Dimensions and area of a shed roof, materials quantity for it, the roof angle (pitch); Number of rafters and their dimensions The lower height field is disabled, but updates as the buyilding width and/or heel height are changed. Custom Gambrels Custom gambrels allow complete flexibility of design with all input fields enabled and few constraints on the shape of the roof other than the lower slope must be greater than or equal to the upper slope Roof pitch is given as the number of inches in height change over the distance of one foot. Dividing by 12 gives the ratio of inches in rise per distance. For example, a standard roof pitch is.

The design of collar tie roof provides greater ceiling height if it is required. This collar tie roof is suitable for the span varying from the 4 to 5.5.This roof is used for a maximum span of 4.8 m. The purpose of the collar tie roof is to extend first floor rooms into the roof space and so limit the largely unused roof space Step 5. Substitute the ceiling length and the difference in height into the equation: Tangent of the angle of slope = (difference in height / length of ceiling). For example, with a length of 20 feet and a difference in height of 1 foot, the tangent of the angle of slope is 0.05 (1/20 = 0.05). Find the angle by looking up the arc tangent of the. Take a look at the planning poral, it gives you a maximum ridge height and pitch your roof accordingly. wiggy, Aug 23, 2019 #2. GateBeam likes this. andyscotland Active Member. There's no minimum pitch, the only requirement is that the roof covering is appropriate. 10 degrees with a flat roof covering (EDPM / GRP etc) would be fine. Slate is. By raising the roof and adding additional roofing, an average of 4,400 square feet of space is saved in a house.But it's not always easy to raise a roof.With a typical 8,000 square feet, there are only a few places where the roof could be raised, such as on the side, to add extra insulation [ If a roof increases in height by four inches for every foot of horizontal run, it is considered to have a 4-in-12 pitch or just a 4 pitch. Talk in terms of pitches and you will always be understood in the roofing universe. ������. Measuring a roof pitch. Ideally you will have safe access to your roof from inside the building

Roof Calculations of Slope, Rise, Run, Area - How are roof

1. ing the right roof gutter sizing
2. To calculate the pitch of a Hip/Valley of a roof, The EDGE has to calculations based on specific points of reference, every time. The EDGE uses Plan View to calculate measurements and to apply a specific formula to its measurements. That formula is the Pythagorean Theorem using the following examples
3. Mean Roof Height (ASCE 7) Per ASCE 7, the Mean Roof Height (h) is defined as the average of the roof eave height and the height to the highest point on the roof surface, except that, for roof angles of less than or equal to 10°, the mean roof height is permitted to be taken as the roof eave height. Visually, AAMA TIR A15-14 illustrates the.
4. The exact calculation of the hip roof with the help of online calculator KALK.PRO - detailed drawings, 3d-model. Calculation of area, pitch and other important dimensions, material consumption. Try calculation for free
5. In other words, this roof truss calculator uses the span, overhang, and pitch dimensions to calculate a rake length. Using this information, you can better estimate how much the roof truss design will cost and what materials you will need
6. ing gutter position on the eave, the pitch of the gutter and the roof slope. Gutter should be pitched 1/16 or greater per foot for proper drainage. Gutter can be run level for appearance but addition downspout will be necessary (See section on Proper Gutter and Downspout Sizing)..

Notes to the table above. 1. Low slope roofs are from 0 to 3 / 12 in pitch. Some sources consider low slope to include 3 / 12 pitch roofs. If asphalt shingles are to be installed on a low slope roof, special steps are required to avoid short roof life and roof leaks Height Above PLate Table -- 3 / 12: Rafter Seat Cut Length -- Each rows shows seat cut length with H.A.P for material size: Material: Plumb height: 1 1/

Roofing Calculato

1. es the height of the ridge board that runs the length of the house. Slope the pitch of a roof brandon craft. The ridge height is 19 to 17th the span an angle of 1250 to 160. Commonly used roof pitches were given names such as greek
2. imum roof pitch for asphalt shingles? I could go with a metal roof, but would rather explore asphalt as the rest of the shed is asphalt on a 7/12 roof. I have read that 2/12 is do-able using a ice water barrier and double layers of felt
3. e downrod length based on installation location height. Why Buy from Del Mar Fans and Lighting
4. - Multiply the roof pitch by the run factor. The result equals the total distance the roof rises. - Calculate the top height of the ridge board. How do you measure for roof covers? Multiply the area by the pitch multiplier to get the roof's square footage. First, multiply the length by the width
5. Divide the height of your roof by the width (not the full width, if you've measured the full-width wall to wall divide this by 2 first!) (H/W), to get your pitch as a percent. Take your pitch percent and press shift (maybe 2nd Function on your calculator) then press tan and than equals - most smartphone calculators have a scientific option.
6. This online roof pitch calculator can assist you in calculating the amount of the construction materials needed to build a single sloping surface type of a housetop, in particular, you are able to estimate the required quantity of the sheeting material (metal tile, asbestos slate, metal slate etc.), sarking boards for sheathing and rafters for trusses, underlay material (rubberoid or asphaltic.

Roof Pitch Calculator - Inch Calculato

1. Once you have the second floor plates set up it is time to put on the roof. With the second floor plan active switch to Roof Mode and draw in your roof. Make any changes necessary such as pitch changes, gables, overhangs, etc. to complete the roof. Once you have the roof drawn the next step is to draw the locations of all hips, valleys, and ridges
2. e the final height of the inside from floor to ceiling. To deter
3. Calculation of a shed roof Enter the required dimensions in millimeters X - house width Y - the height of the roof C - the size of the eaves B - The length of the roof Help The program is designed to calculate the single-pitch roof materials: the amount of sheet material (Onduline, Nulin, slate or metal tiles), underlay material (asphalt, roofing), number of boards lathing and rafters
4. ed by dividing the vertical rise in inches for every horizontal twelve-inch length
5. Obtain the pitch, or slope angle, of a roof by calculating the ratio of the change in the roof's height to the corresponding horizontal distance. Roof pitch is expressed in ratios of 12 because it is measured by the foot. For example, a roof with a 6:12 pitch rises 6 inches for every horizontal foot
6. Calculating the heel height on a standard truss can be done by using the formula: Total Heel Height = H+Butt Cutt To work out H we need to use the following formula where H = y. y = z/cosx For example: 'z' is at 90° to the rafter's pitch of 3/12 and in this example is the rafter's section size
7. The crucial measurement you need to take is from the highest point, directly under the roof ridge, vertically down to the top of the joists below. This can be done with a tape measure, ideally, a metal one that will remain straight. For a conversion to be practical, the height needs to be at least 2.2 metres To Calculate a Saltbox Roof. Select Saltbox from the Roof Type dropdown list or select the corresponding button on the toolbar. The preview window displays an elevation view of the roof that updates dynamically to reflect the actual dimensions of the roof, including the difference in elevation between the front and rear wall plates Some roofing calculators use Pitch and House Area but unfortunately, this approach is not the most precise way to get the roof area because you cannot use it for more roof shapes. Other roofing calculators ask for a lot of dimensions in order to determine a more precise total roof area For example: if the ratio of the roof pitch is 1:1, we are talking about an isosceles triangle and the roof pitch can be given as 45°. To calculate the pitch we use the tangent function, meaning 1:1=1, where tan 45°=1 To express the roof pitch as a ratio, the height or so called rise will be given as a value of 1 Typically, the leeward drift height, hdL, is greater than the windward drift height, hdw, unless the length of the lower roof is considerably longer than the length of the upper roof. Windward drift results from snow blown against a projection or wall below a high roof  The pitch fraction represents a certain amount of vertical rise over the entire span. For example, given a roof with a rise of 4 feet and a span of 24 feet, the pitch is 1 to 6 pitch, which can be expressed as the fraction of 1/6. A 12 to 24 pitch is expressed as 1/2. The term pitch and slope are often used. A 12/12 roof (pretty steep) will require a taller chimney stack and definitely more lumber. However, the roofing material could last 50% longer and it will require less maintenance. Determine the Rise and Run To Calculate the Area of Your Porch Roof To calculate the area of your roof, first determine its rise and run (slope or pitch) Our handy roof truss design calculator calculates the rake length of your roof by using the span, overhang, and pitch measurements. Pitch - This is the incline of the roof. It will be expressed as a fraction. If you think back to your early geometry classes, you might remember that the pitch of a triangle is the rise over the run Standard pitch of roof in degrees, ratio & fraction for house. Pitch of roof lower than 4/12 have a slight angle called as low slope roof, pitches of less than 2/12 considered as flat roofs, pitches higher than 9/12 are called as steep slope roofs, pitches ranging between 4/12 to 9/12 is considered as conventional roofs pitch suitable for most of residential house