Owning your own home

Anyone know anything about the process of converting a loft? Ours is part done (has a window) and we want to finish it off... Spoke to a quantity surveyor friend who said we'd need an architect to draw up plans - surely it's not that complicated?

Our house already had the loft converted when we moved in, but it wasn't really usable as a bedroom, so we had it re-done a couple of autumns ago. Building regulations had changed since the previous conversion, so we had to get it completely re-done, including having architect drawings done to satisfy the demands of building regulations. Areas like weight loads, insulation and fire safety all have to be met.