I have bought a 2-storey landed terrace house (land about 1650 sqft) and plan to add a 5m extension at the back, 5m x 6m wide (ground floor and 2nd level), and the extension has an attic floor and new roof. I also plan to change the entire roof, the existing roof is 12m (L) x 6m (wide). Will also need to makeover the house (simple tiles, etc). What is the expected A&A costs or reconstruction cost? Thank you.