It is 18 x 6 as that is all the space I have. It is bespoke and uses 19mm log lap on the outer. It is a pent roof 7 foot at the front and 6 at the back. Have no idea on the roofing material but it is guaranteed and they install it.Nice! How big is this "Shed"? My 12 x 8 x 8 cost me about £2k but it is all 4 x 2 studwork and plywood lined and shiplap outer sheathed with a 25 year rubber roof. Worth every penny though.