There are three different types of lead available for building materials.
When using lead sheet:
More Information can be found on the Lead Sheet Association (LSA) website.
Health and Safety – Lead Sheet Training Academy
ILA-LeadworkerSafetyDoc2-UK-AW (leadsheet.co.uk)
The angle of a roof is a measure of the underside of the roof from the horizontal as shown in the diagram. If you can access the rafters in your property and can measure the angle it is this angle you are measuring.
The slope of the roof (Pitch) is the ratio of vertical distance (Rise) to Horizontal distance (Run). It can be calculated using a set run of 12” and finding the rise at that point on the roof (See diagram).

The slope ratio (Pitch) can be converted into an approximate angle using the following table for your convenience.
| Roof Pitch | Angle |
| 1/12 | 4.76° |
| 2/12 | 9.46° |
| 3/12 | 14.04° |
| 4/12 | 18.43° |
| 5/12 | 22.62° |
| 6/12 | 26.57° |
| Roof Pitch | Angle |
| 7/12 | 30.26° |
| 8/12 | 33.69° |
| 9/12 | 36.37° |
| 10/12 | 39.81° |
| 11/12 | 42.51° |
| 12/12 | 45.00° |
Although very simple this sometimes proves confusing depending on where you view the structure from but hopefully this picture will help.
Left and right are as you look at the dormer or chimney breast from the ground. We class the left side as the left hand and the right side as the right hand. We use which side of the structure the product goes on rather than which side of the roof it is on. Sometimes a phone call can help clarify things with awkward and unusual situations so please feel free to contact us.
The Gauge is the distance between your roof battens and the Lap is the distance each tile overlaps the one beneath it.
The length of a soaker should be the gauge + Lap + 25mm for fastening if required.
LEADWORX TOOLS
Calculate from measurements, or estimate the angle from a photograph.
Measure the vertical rise and horizontal run between the same two points.
Use the same unit for both, such as mm or cm. Run is not the sloping roof length or automatically the full building width.
Enter your measurements to begin.
Enter measurements first.
These formats describe the same slope; they are not product size recommendations.
Use a square-on view of the roof profile, with a known horizontal reference in the same plane.
The photo box opens your camera on supported phones and tablets. On a computer, choose a photo file or drop one into the box.
Processed on your device by this tool. JPG, PNG or WebP, up to 20 MB and 24 megapixels. Export HEIC as JPG first.
Tap the photo box or choose a saved photo.
Tap four points: two on the roof slope, then two on a level reference. Drag points to adjust. Use long lines for a better estimate.
Focus the photo. Arrow keys move the marker; Shift moves 10 pixels. Enter adds a point. Select a placed point below to adjust it with the arrows. Escape returns to the free marker.
No points placed.
Mark the photo first.
The reference line corrects camera tilt, not perspective or lens distortion. A photo cannot guarantee the angle needed for manufacture.
Check the pitch before ordering made-to-measure leadwork. Measure only from a safe, accessible position.