What a reroof actually costs, and what moves the number

Nobody can price a reroof properly from the street, and the three things that move the number most are the three you cannot see from there. Access comes first. A single-storey house with a clear boundary is scaffolded in a day; a two-storey on a slope with a neighbour's fence in the way is a different job before anyone touches the roof. Pitch is next, because it decides what material is even allowed and how the crew has to work. The third is what is underneath, and it is the one that turns into a variation. We allow for inspecting it and we quote the fix separately when we find something, rather than padding the original number to cover a problem you might not have.