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Friday 9am to 3pm, closed on weekends

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Common measuring terms


The roof pitch is the angle of the slope of the roof. This is used to calculate flashing angles at the ridge and eaves.

To help calculate your pitch you can use on external online calculator by clicking here

The formulae (formula) for finding angle and sides of triangle can be easily remembered using the sentence -Old Harry And His Old AuntSin (q) = Old/Harry = Opposite/Hypotenuse
Cos (q) = And/His = Adjacent/Hypotenuse
Tan (q) = Old/Aunt = Opposite/Adjacent

Right Angle Triangle - Online Angles & Sides Calculation.

Mono pitch roofs

Width: When calculating roof cladding the width measurement will refer to the direction of lay. This allows us to calculate the number of sheets required based on the cover width of each sheet.

Length: The length will refer to the length of each sheet. This will correspond to the fall or the distance the water with travel from ridge to eaves. Always remember to include an overhang of around 50mm to 100mm to allow water to run off.

Sometimes the width and length may seem the wrong way round. (e.g. The width of the roof may be more than the length of the sheets) It is very important that the correct measurements are supplied to ensure your roof sheets are manufactured correctly.

Apex roofs

Ridge length: Similar to the width measurement on mono pitch the length of ridge is required to determine the amount of sheets required each side of the roof.

Ridge to eaves measurement: The ridge to eaves measurement will determine the length of the sheets required. A gap of approx. 50mm should be left at the ridge (or tip of the apex) as sheets from both sides should not be touching. Also an overhang at the eaves (or gutter end) for water to run off should be accounted for.

For further information on measuring per roof type please click the link below:

Measuring your roof