Our loft, in a 1930s semi cost £50k.
It was a permitted development.
We’ve had a huge dormer put on.
This included everything apart from the fire doors to the rest of the house and the bathroom.
We also had the roof replaced and new rainwater goods.
We hired a local loft conversion specialist who employed an architect, structural engineer and took 4 weeks to complete.
We managed two decent double bedrooms and a bathroom that is bigger than our main bathroom.
First step was the boss coming round and measuring the loft.
We told him what we wanted and he came up with a price.
The architect came round and drew up plans.
We mucked about with them and came to a final price.
Work started 12 months later.
The foreman suggested we make better use of the space and so the floor plan was pretty fluid.
At various points building control (one of these companies on behalf of the council) came out and assessed the work.
You’ll need to think about getting power up there? We had the mains fuse upgraded and a new consumer unit and the easiest route was to run armoured cable up the gable wall.
Best thing we’ve ever done house wise.
Just bear in mind that pretty much every other existing internal door (except bathrooms and toilets) will need to be changed for fire doors - and you’ll need suitable smoke alarms - just buy AICO - ignore everything else.
Happy to share plans of what we did if that helps?