RACHEL AND JONNIE’S TIPS

1 Think about how you’re going to use your garden room. If it will be in regular use as an office, it needs to be warm and comfortable all year round. We have good insulation and underfloor heating. 2 It’s easy enough to run up wiring to an outside room, but we didn’t opt for plumbing – this can add another cost. 3 Don’t leave smaller jobs until later. If you need, say, a blackout blind, put it in during the build, or it will end up not getting done!

THE OCTOPOD Dimensions 5m x 3.6m Build time 20 days Cost £30,000 See studiobenallen.com