I am getting an attic conversion but will require planning permission. The builder has told me I will need a architect/engineer to do up the plans and sign off the work. I have a quote of approx 25K for the builder & should take about 3 or 4 weeks. But when I contacted an Architect, I got a quote of 3.5K, this seems a bit expensive to me. Has anyone out there got an Architect/Engineer to Do up plans,Apply for Planning permission,site visits and sign off work... if so how much did it cost? ... is 3.5K excessive?