What is the standard roof pitch for a UK house?

Most traditional UK houses have a roof pitch between 30° and 45°. This 'steep' pitch is designed to allow heavy rainfall and occasional snow to shed quickly, protecting the structure from water ingress.

What is the minimum pitch for a tiled roof?

The minimum pitch depends on the specific tile. Many modern interlocking concrete tiles can go as low as 15°, whereas traditional plain clay tiles usually require a minimum of 35°. Always check the manufacturer's specification.

How do I calculate roof pitch from rise and run?

To find the angle in degrees, you use the tangent function: Pitch = arctan(Rise / Run). For example, a rise of 2.5m and a run of 5m gives an angle of approximately 26.6°.

What happens if a roof pitch is too low?

If a roof is too flat for its covering material, water can be blown under the tiles by the wind (known as 'capillary action' or 'wind-driven rain'), leading to leaks and timber rot.

What is the standard roof pitch for a UK house?

Most traditional UK houses have a roof pitch between 30° and 45°. This 'steep' pitch is designed to allow heavy rainfall and occasional snow to shed quickly, protecting the structure from water ingress.

What is the minimum pitch for a tiled roof?

The minimum pitch depends on the specific tile. Many modern interlocking concrete tiles can go as low as 15°, whereas traditional plain clay tiles usually require a minimum of 35°. Always check the manufacturer's specification.

How do I calculate roof pitch from rise and run?

To find the angle in degrees, you use the tangent function: Pitch = arctan(Rise / Run). For example, a rise of 2.5m and a run of 5m gives an angle of approximately 26.6°.

What happens if a roof pitch is too low?

If a roof is too flat for its covering material, water can be blown under the tiles by the wind (known as 'capillary action' or 'wind-driven rain'), leading to leaks and timber rot.

Roof Pitch & Angle Calculator

Professional calculation of pitch, ratio, and rafter length for UK builds.

Rise (Vertical Height in m)

Run (Horizontal Distance in m)

Visual Guide

Roof Slope

Pitch Analysis

UK Minimum Pitch:

Most interlocking concrete tiles require a minimum pitch of 15° to 22.5°. Natural slate usually requires at least 20° to 25° depending on the lap.

Roofing Engineering: Understanding Pitch & Slope

Why Pitch Matters

In the UK construction industry, 'pitch' refers to the steepness of a roof. It is critical for two reasons: drainage and material compatibility. Every roofing material—from clay tiles to EPDM rubber—has a minimum recommended pitch to remain waterproof.

A roof that is too flat for its tiles will leak during heavy wind and rain, as the water can be forced up and over the top of the tiles.

Minimum Pitch Guide

Concrete Tiles15° - 22.5°

Natural Slate20° - 25°

Plain Clay Tiles35°+

Rise, Run & Rafters

To calculate your pitch accurately, you need two measurements:

Rise: The vertical height from the wall plate to the ridge.
Run: The horizontal distance from the wall plate to a point directly below the ridge (usually half the span for a symmetrical gable roof).

The Rafter Length (also known as the hypotenuse) is the diagonal distance you need to order your timber or calculate tile coverage.

Weather Performance

In coastal or exposed areas of the UK, building regulations often recommend increasing the pitch or the "overlap" (lap) of the tiles to combat higher wind speeds and horizontal rain.

UK Roofing Pitch FAQ

Structural Safety Disclaimer

Roof design involves complex load calculations (snow load, wind load, and dead load). While this calculator provides geometric estimates, all structural roof designs must be verified by a qualified architect or structural engineer to ensure they comply with BS 5534 (The British Standard for Slating and Tiling).