We are thinking of an extension across the back of our bungalow. Approx 8 m wide and go out 4 - 5 m This is the apex end of the property and am wondering if there would be a massive difference in price for a flat roof compared to carrying on the shape of the roof as the rest of the bungalow. Just that we have a conservatory that will be removed and as it isn't very old would rather like to use it. That has an apex roof so will not fit on a side wall.