Formula Question

Measure the eaves as their own line and turn that length into the 50 mm strip. Using a sloped roof type keeps the pitch included:

1. Measure the roof as an area takeoff with a Sloped Area measurement type, so the pitch is applied to the roof area automatically.

2. Add a Linear takeoff (not Sloped Linear, since the eave is level) and draw it along the eave edges only.

3. Give that linear takeoff an item with the same units as your roof item (m²). If the 50 mm is measured down the roof surface, use this formula:

[Linear:m] * 0.05

4. If the 50 mm is measured on the plan, use this formula to include the pitch, with `Roof` swapped for your roof takeoff's name (for a roof pitch set as rise/run):

[Linear:m] * 0.05 * sqrt([./Roof/rise]^2 + [./Roof/run]^2) / [./Roof/run]

5. If the roof pitch is set in degrees, use this instead:

[Linear:m] * 0.05 / cos([./Roof/degrees] * pi / 180)

6. For one combined total, put both takeoffs in a folder and give the folder an item with this formula:

sum('qty', {kind: 'item'})

If every edge of the roof gets the 50 mm (rakes too), there's a quicker way. Right-click the roof shape, choose Offset, enter 50 mm, then delete the original shape. The pitch is applied to the new outline automatically. You'll need to run Offset again if the roof outline changes later.