"I left everything to do with planning permission to the builder, who was from a trusted local firm that we had known for a long time and had a very good reputation"
"An architect drew up the plans and I didn't have to worry too much about planning permission. It took quite a long time to actually get the planning permission though."
"Again, I was able to leave all the details of ensuring that the work complied with building regulations to the builder, who was adamant that he would deal with all of that. We submitted plans in advance, and then the Building Control Officer visited the property four times in total while the work was being carried out.
The Building Control Officer spotted a number of issues with the work-in-progress - originally I planned to take down two internal walls rather than one, but couldn't because it turned out to be a supporting wall, and then the ground underneath what was going to be the new room was newly-made ground, and the Building Control Officer made us dig a lot deeper than we had originally planned to make sure that the foundations were solid."
What I would have done differently
"Think about the knock-on effect of each piece of work. This was one thing we didn't do - for example, because we were moving a boiler, we knew we'd have to replaster and paint one room, but then in the end we had to do most of the ground floor as it would have looked odd to do one room and not the one it led into."
"Agree all work beforehand in writing, not just the bare bones of the contract, but discuss how both parties interpret the extent of each piece of work. We did this with our builder, and it avoided any stress or miscommunication at the end of the job."