How long does an extension take to build?

People ask a lot of the time about what the time frame, the programme of the build will be. Now, it’s going to vastly vary depending on what you’re having done. If it’s just a small rear addition with no work internally, just literally a box on the back, it could be 12 weeks. You’ve got foundations and brickwork to go up, insulation floors, block and beam, drainage, et cetera.

So if you start getting into hidden steels and pad foundations that are inside the current house, and then you’re staying in the house, there’s a lot of other parameters that we need to work with that could potentially push it to 16 weeks.

If you’re going towards quite a nice size build, where you are then affecting the inside of the house as well, you could be into six months. And full builds, like we’re doing a big build on a house in Loughton at the moment, that’s probably going to be 13 to 15 months in total project timeline, purely because finishes, details, making sure everything works with all different bits and pieces. We’ve got an interior designer on the project as well, so there’s lots and lots of moving parts that all need to be programmed and all fit in with each other.

And sometimes you have to wait for details to arrive, not because people are slow, just because they take time to work out, because there might be three or four working parts behind that decision being made, like engineers, designers, then the client, then it goes back to the designer, just for the final sign off. The drawings done by the architect then get issued to us, because ultimately, as a builder, we are colour by numbers. We have to build to the drawings and specifics that are designed and delivered to us.

So it can vary vastly, but I would say the shortest time period for a rear extension is probably anything between 10 and 12 weeks.