Roof Pitch Angles: How To Calculate Your Roof Pitch
Understanding your new roof’s pitch and slope is incredibly important. This helps you understand how excess water, snow, or debris falls off the roof, which also helps guide you to the right type of shingles or roofing materials you need. We’re here to teach you how to easily calculate and estimate your roof pitch angles manually.
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What Roof Pitch Is Walkable
A roof pitch of 6/12 or less is considered easily walkable, and no extra precautions are required. A roof of pitch 7/12 is manageable, but caution should be taken. Pitches between 8/12 and 10/12 are also considered walkable, but it is not advisable and, if you have to walk on these roofs, extreme caution should be taken. Roofs any steeper than this are considered not walkable, and special equipment or scaffolding is required. Please do not take risks on roofs, as the fall can be fatal.
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How Do You Calculate Roof Pitch Angles
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.
If measuring a physical roof, get a ladder, and place it on a solid surface. Climb up to the roof with a carpenter’s square set to a foot of length. Place it above the roof so it forms a right triangle with the slope of the roof.
Look at the measurement where the carpenter’s square meets the roof, and make a note of this number. For example, assume the roof has a pitch of 4 inches. The roof should intercept the carpenter’s square at the 4-inch mark. This is a ratio of 12, so it would be a 4:12 pitch.
Dividing 4 by 12 yields a decimal result of 0.3333. This number is needed for the next step.
Open a calculator application or use a scientific calculator. Enter the decimal, then press the key labeled “tan,” “arctan” or similar. The decimal 0.333 converts to an angle of 18.434 degrees.
Types Of Roof Pitches
Lets take a closer look at the advantages and disadvantages of the different roof pitches. Have a look below to see the advantages and disadvantages of the various roof pitch types.
Its important to remember that roof pitch doesnt necessarily have to refer to a gable roof it can also be a lean-to, saltbox style or another type of roof with a flat surface.
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How Roofslope Affects Your Roofing Cost
Slope factor is key when it comes to calculating cost. If your roof falls into the steep-slope category, expect your installation cost to be higher. Once the roof is at a steepness that a contractor or roofer does not consider walkable, extra caution, time, and equipment are all required to ensure safety. This all adds up to being an extra expense.
You also have to factor in that as your roof pitch increases, so does the roof surface area. The larger the surface area and if you factor in a steep roof, the more material would be needed to cover it.
As a general rule, the steeper the pitch, the cost of installation rises. Roof steepness and the surface area of your existing roof, especially one that needs a roof repair, are key factors to consider when it comes to cost.
Does A Shed Roof Need An Overhang
Having a roof overhang protects the walls and the base of the shed. The roof overhang gives a lot of protection above doors and windows from rain. At the bottom of the shed wall the fact that water from the roof is being directed away from the shed means that the base of the shed gets less persistently damp.
Read Also: How Do You Seal A Tin Roof
How To Measure Roof Pitch
Knowing the pitch of your roof is useful when designing an addition, installing skylights, or cutting new rake boards. Here’s an easy, safe way to determine the pitch from inside your attic.
What Is The Average Quote For Getting A Roof Pitched
There are a lot of factors that will affect how much getting your roof pitched will cost design, style, accessibility, cost of labor etc. In the USA, you can expect to pay between $3.19-$4.43 per sq.ft. for asphalt shingles. If you choose another material, such as metal or wood, the range is $7.35-$10.73 per sq.ft.
In the UK, the price of getting a roof fitting is £72-£75 per square meter. These are only estimates though, talk to your neighbors to see what roofing costs in your area.
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Estimating The Cost Of The Roof
Once you know the area of the roof, you have to decide on the scope of works. Do you want to build the roof from scratch, or maybe replace the old layers? You also need to decide on the finishing material. For example, asphalt shingles will be less expensive than clay tiles.
After you’ve made all of these decisions, it’s best to contact your local contractor and ask about the cost of both materials and labor per square meter or square foot of roof area. Remember that this unit price should include all additional elements such as fasteners, as well as the cost of removing all layers and disposing of them .
The most typical cost of roofing falls between $2 and $4 per square foot . If the price proposed by your contractor deviates from these values, it is advisable to check with other contractors before starting the works.
If you cannot contact any contractor, calculate the cost of materials and multiply this price by 2.5. You will obtain an approximate price including labor, assuming that 40% of the cost is taken by the materials and 60% by the labor.
The last thing you have to do is to multiply this cost by your roof area and voilà, you now know the total cost of your roof! Remember that the real cost might differ from this value a bit due to waste, so plan ahead and assign more funds to this construction work.
Make sure to take a look at our concrete slab cost calculator, too!
Estimating Roof Pitch & Determining Suitable Roof Types Diy Guide
So, its time for a new roof, or perhaps you are planning a new home construction project and are considering what your new roof should look like. Surely, you have heard about all the exciting new roofing materials available today and are eager to get started.
However, before you can make the call on what to put on the roof, you need to know the pitch or slope of the roof!
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Three: Measure The Total Rise And Run
If you know the total height of the peak and the roofs width, you can also find the pitch with a little math. For example, if the peak is 4 feet and the total roof width is 20 feet, then the total rise is 4 feet, or 48 inches.
The total run is the distance from the peak to the edge of the roof, which in this case is the total width divided in half, which is equal to 10 feet or 120 inches.
Since the pitch is the rise over a 12-inch run, you can divide the run by 12 to get the multiplier, in this case, 120 ÷ 12 = 10.
Then, divide the rise by the multiplier to get the pitch, e.g. 48 ÷ 10 = 4.8. The pitch of this roof is 4.8:12. The calculator above can handle much of this math.
Search With The Roof Area Calculator
Accounting for dormer windows and other structures that might share a different pitch, the first step is to calculate the footprint of the roof, or the area it occupies.
Login to SketchAndCalc and select Show Maps from the Menu.
Search the homes postal address from the map controls that appear in the top left corner.
When zoomed in, switch to satellite view.
Identify the roofs structure. Regardless of complexity , if the roof has a single pitch or incline throughout you can simply draw the perimeter of the entire roof using SketchAndCalcs line drawing tools.
TIP: Line length labels are displayed as you draw. If you find these labels obscure the view of the roof just switch them off from Menu > Settings > Application. You can also adjust the grid transparency and drawing line weight.
If the roof has multiple pitches, such as those found on dormer windows or porches you will need to draw these separately. After drawing the perimeter of the roof, add a new drawing layer with the plus symbol found in the bottom right corner. Then proceed to draw the surface area of the roof that has a different pitch. Using dormer windows as an example, youll add a new layer after drawing each dormer.
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How To Calculate Roof Pitch As A Ratio
The traditional method of measuring roof pitch is to display it as a ratio of X:12. This is done by measuring the number of inches a roof rises vertically for every 12 inches it extends horizontally. This is simple to do, and youll need the same tools and access to your roof space as above.
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Standard Pitches: 3/12 Through 9/12
Standard pitch roofs are the common roofing pitches you’ll find on the main living areas of residential homes. Unlike low slope roofs, areas that have a standard slope can use regular roofing shingles without worry. Because there’s enough of a slope, you don’t have to worry about water drainage as much as you would with something like a 2 over 12 low slope roof.
In degrees, standard roof pitches are between 14.04 degrees and 36.37 degrees.
Minimum pitch for shingles
3 over 12 is the minimum slope a roof needs in order to qualify for roofing shingles.
Some roofers still opt for low slope materials with a 3 over 12 pitch, but this is not entirely necessary and just adds to the cost of your project.
Steepest standard pitch
A 9/12 roof pitch . is the steepest standard slope.
Anything above a 9 over 12 is considered steep slope.
To Measure Your Roof Pitch:
1. Set your ladder on the side of your house so that you can safely access the down slope edge of the roof. You will not need to get on the roof for this step, just make sure that you can touch the edge of the roof from the ladder. As you face the house, the roof should slope up from the left to right, not away from you.
2. Hold a framing square up against the roofline so that the long end of the “L” points toward the center of the roof and the short end points toward the ground. Essentially, you are forming a right triangle with the long and short sides of the framing square – the roof edge forms the third side.
3. Position the framing square so that the long end meets the edge of the roof at the 12″ mark.
4. Level the square horizontally.
5. Read the measurement on the short end that is standing up vertically from the roof.
6. :::Remember:::Rise over run. The rise is the measure on the vertical leg the run is the 12″ measurement on the horizontal leg. So if the vertical measurement is 6, the roof has a 6/12 pitch.
Roof pitch relates to the slope and inclination angle of a roof in building construction. The primary purpose of a pitched roof is to redirect rainwater. In general, the pitch of the roof is proportional to the amount of precipitation. Houses in areas of low rainfall frequently have roofs of low pitch while those in areas of high rainfall and snow have steep roofs.
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What Roof Pitch Is 30 Degrees
A 30° roof pitch is roughly the same as a 7/12 roof pitch. To convert from degrees to the American ratio:
How To Find The Rafter Length
Youll also need to find the length of your roof from the eave to the ridge, also known as the rafter length. How to do this? Remember your middle school math! Use the Pythagorean theorem a^2 + b^2 = c^2. So for our 8×10 shed, youll do 4^2 + 2^2 = x. The answer is 20. But you have to take the square root of 20 to find the length, and it ends up being around 4.5.
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Using Slope & Pitch Interchangably
Because home construction is now more complex, remodeling as a whole is too! And contractors have been forced to adapt. In doing so, most contractors are now using slope and pitch interchangeably, especially when writing roofing estimates.
When reading about pitch and slope, the most common explanation you’ll find is actually a hybrid of the two. You’ll see a measurement referred to as pitch but the real measurement is slope . Historically, there’s a few reasons for this…
How Roof Pitch Determines Suitable Roofing Systems
Flat and nearly flat roofs cannot be covered with shingles or shakes of any material since there is not enough angle to combat the danger of blow-off. For that reason, flat roofs are limited to these types of covering materials:
Tar and Gravel. Alternating levels of hot asphalt and heavy roofing felt finished with a gravel coating can be applied to a flat roof for protection. Typically, between three and five layers are built up. The cost for this utilitarian roof covering lies mostly in the labor and will vary greatly depending on the location of the building.
For a 2,000 square foot roof expect to pay around $3,500 for materials and supplies and upwards of $9,500 for professional labor. Built-up roofs are not a DIY project and will require professional installation but the waterproofing for flat roofs cannot be beat. A built-up roof can be expected to last 20 years.
Modified Bitumen. Historically, the word bitumen has been used interchangeably with asphalt and tar. It is a naturally occurring goo that develops from millions of years of decomposing organic material and has been used since prehistoric times as a sealant.
In modern roofing, bitumen is infused into plies of polyester or fiberglass to create a weatherproofing roof material. The installation technique is similar to building up with tar and gravel, but the plies are less expensive by half about $2,000 for materials and supplies. Labor is a bit faster and expect a tab of about $8,500.
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How To Find Existing Roof Pitch
Sometimes we need to know our existing roof pitch to install new roofing material or for building inspection. Here are a few methods to easily find the roof slope on your existing shed.
Using 48 Carpenters Level and Measuring Tape
Go on your roof and put one corner of the level on your roof, then bring it up, so it is level with the earth. Lower the measuring tape to the surface of the roof 12 away from where the level meets the roof. The measurement from the roof to the bottom of the level is the rise, over a run of 12.
How to Measure Roof Pitch From Ground
Measure the width of your shed from ground level and divide by two thats your run. For the rise, know that vinyl and clapboard siding typically have 4 exposures before the next course starts above and below it. Find the exposure that is perpendicular to where the roof begins at the side walls of the gable end of the shed.
Follow that exposure to the center of your shed and count the number of exposures until you get to the ridge. Multiply by 4, then divide by 12. You have your rise over run in feet.
Using a Framing Square
On a finished shed, get a ladder and prop it against the slope of one end of roof line. Using a small level atop the flat end of your framing square, put the pivot point against the edge of the roof and bring the square and level up to horizontal with the ground. Use the markings on the square to see where the roof edge lines up with the pitch notations.