hi guys i have a flat roof across the garage and kitchen extension the size is 13mx3m thats giving a lot of extra and would need overboarded to the excisting roof .The roof itself is fine to my knowledge but there is a dip in the middle of the roof across 2 m span where the person who built it many years ago used uneven joists and it creates a pool on the flat roof .What would be and average cost in the westmidlands for a gerneral guide price to do the job also is there any one in in midlands on here. cheers in advance