How to measure roof pitch in the UK
The pitch of a roof is the angle or slope that the roof is built at and if you have two or more sides of your roof that meet in a peak at the top of the structure, you have a pitched roof. In the UK, over 93% of properties have a pitched roof meaning if you are unsure what type of roof you own, it is more than likely a pitched one.
Measuring the pitch of your roof is important if you are carrying out repairs or work to your roof. From working out the number of roofing materials you will need to determining how water drains away from the property, calculating the pitch of your roof is something that is very important when it comes to roofing repairs or extensions.
However, if you have never worked out how to calculate roof pitch before, it can seem difficult to know where to even start. Fortunately, as one of the leading roofing companies in Melksham, we have years of experience in calculating roof pitch. For this reason, we have created this comprehensive guide on how to work out the pitch of your roof with two different easy-to-follow methods.
Need help working out the pitch of your roof? Look no further than A L King Roofing. We are the leading roofing company and roofing merchants in the Wiltshire area. Visit our merchant centre in Melksham or call us on 01225 705918.
Why is a roof pitch important?
The angle of a roof pitch plays a pivotal role when it comes to choosing your next roof or making necessary roofing repairs. Each type of roofing material requires a minimum recommended pitch angle in order for the material to be installed safely and effectively on your roof.
If you try to install a roofing material outside of its recommended roof pitch it can compromise the stability of the roof and be a major safety hazard to people living inside and near the property.
For this reason, it is pivotal that you calculate the pitch of the roof accurately to ensure you choose the correct materials for the project at hand.
How to work out pitch of roof in degrees
As a general rule of thumb, the steeper the roof slope, the higher its pitch. With that being said, it is still necessary to work out and calculate the roof pitch. An easy way to do this is by working out the pitch of the roof in degrees.
Firstly grab a measuring tape, spirit level and a calculator then head to your loft space. Next, in order to work out the roof pitch, you will need to know the length of the rise and the run of the roof. The rise of the roof is the vertical distance the roof rises for every horizontal foot of the roof.
- Measure the run of the roof with a tape measure (the horizontal length that spans between the peak of your roof and the wall).
- Next work out the rise by using a tape measure. The rise is the height of your apex above the wall structure.
- After this, you will need to calculate the tangent by dividing the rise by the run (rise ÷ run = tangent).
- From here use trigonometric functions to convert the tangent to degrees. The arctangent (inverse tangent) function is commonly used for this purpose. The formula is:
Pitch Angle (in degrees) = arctan (rise ÷ run) - Grab a calculator and plug in the rise and run values into the arctangent function on a calculator to find the pitch angle in degrees. The result will give you the pitch angle of the roof in degrees.
Our example:
- Measure the Run of the Roof: If the run of the roof is 20 feet (the horizontal length between the peak of the roof and the wall).
- Work out the Rise: Let’s say the height of the apex above the wall structure (the rise) is 6 feet.
- Calculate the Tangent: Divide the rise by the run to find the tangent:
6.2 ÷ 20 = 0.3
- Convert Tangent to Degrees using Arctangent Function: Use the arctangent function to convert the tangent to degrees:
Pitch Angle (in degrees)= arctan(0.3)
- Use a Calculator: Plug the value into a calculator. Press “arctan” or “tan^-1” and input 0.3.
- Finalize the Calculation: So, the pitch of this roof is approximately 16.70 degrees.
How to work out roof pitch as a ratio
Ratios are widely used in construction to describe roof pitch and provide an easier understanding compared to a percentage. For this reason, you may want to work out the roof pitch as a ratio instead.
Similar to working out the percentage of your roof pitch you will first need to make sure you have a measuring tape, spirit level and a calculator and head to loft of your property.
Again you will need to calculate the rise and run of the roof to understand the pitch ratio.
- First, you need to measure the rise. This is the vertical distance from the bottom of the roof to the highest point (ridge) of the roof.
- Next measure the run. This is the horizontal distance from the bottom of the roof to the point where the rise measurement ends.
- Finally, calculate the pitch ratio. Divide the rise by the run to get the pitch ratio. This will give you a ratio such as 4:12, where the first number represents the vertical rise and the second number represents the horizontal run.
For example, if the rise of the roof is 4 feet and the run is 12 feet, the pitch ratio would be 4:12.
If you have the measurements in different units (e.g., inches instead of feet), ensure they are in the same units before performing the calculation.
Conclusion
In conclusion, calculating the pitch of your roof can be a complex and confusing task however hopefully you now have a more comprehensive idea of what this includes and the reasons for it. Figuring out the pitch of your roof is useful for any work that is being done to your roof from roof repairs to tile replacements. If you need help calculating the pitch of your roof and live in the Melksham area, speak to a member of the team today on 01225 705918.
If you live in the Melksham, Bath or Bristol area, here at A L King Roofing, we provide a reliable, affordable and high-quality roof repair service. Originally starting out in 1979, A L King Roofing has over 40 years of experience in the roofing industry from repairs and new roof installations.
Furthermore, we even provide a selection of high-quality roofing materials such as different roofing shingles and replacement shingles which you can find in our roofing merchants centre in Melksham. Speak to a member of the team on 01225 705918 and discuss all your roofing requirements.