How do roofers price up a new roof? I have been quoted £5k and £2800 for the same roof.
"Happiness is like a butterfly, The more you chase it, the more it will elude you, But if you turn your attention to other things, It comes and sits softly on your shoulder."
Like with any other job estimates. Profit margins vary greatly. I would get a third to compare with those two. I used roofers that my old company have used on their properties. With big jobs like this it's always best to go on recommendation, even if that means knocking on the door of someone's house who you've noticed recently having work done to ask them what they thought.
*It is not necessary to understand things in order to argue about them. -- Pierre De Beaumarchais