Roof measurements
Gav,
A good rule of thumb is to take the total square footage of the house and add 1/3 to allow for the pitch.
Example-- 2,000 sf x .333= 666 sf. 2,000 sf + 666 sf.=2,666 sf.
There will be an article in CLEANER TIMES mag. in May, which I participated in, that explains all about roof cleaning.
Happy Cleaning,
Ron