When London homeowners need more space, two options come up again and again: a garden room at the end of the plot, or a rear extension that grows the house itself. Both can work brilliantly. This guide compares garden room vs extension London families face — cost and disruption, permitted development, insulation and year-round comfort, services, and when we recommend which. We are RJS Innovative Building Ltd, a Which? Trusted Trader and FMB builder in South Woodford.
There is no universal winner. The right answer depends on your garden size, how you use the house, planning constraints and how much disruption you can live with.
What each option really gives you
A rear extension adds heated, connected floor area to the main house — typically a kitchen-diner, family room or expanded living space. A garden room sits separate from the house and can be an office, gym, hobby room or guest space. Quality varies enormously, from lightweight summerhouses to fully insulated buildings designed for year-round use.
