Just bought a new house that has a double length single garage with a flat felt roof,I'm thinking about converting it to a pitched roof to allow a bit of extra headroom and storage, still only going to felt it to avoid too much extra weight, the garage is single skin brick, how feasible is this? would I need to buy made up trusses or can I make my own up? and not sure how to attach the trusses to the main part of the garage is there some kind of fixing to attach the cross members to the upright walls...any advice would be greatly appreciated...thanks