Sussex · 7 min read
How Much Does a Garden Room Cost in Sussex?
A line-by-line look at where garden room budgets go in Sussex, and the specification choices that separate a ten-year building from a thirty-year one.
Garden room lit at dusk beside a firepit terrace
Quotes for garden rooms in Sussex vary wildly, and the headline price is rarely comparable between suppliers. The differences are almost always in the base, the build-up and what is excluded.
The cost breakdown
- Groundworks and base - screw piles, a ground beam or a reinforced slab. Site access and levels swing this line item more than any other.
- Structure and insulation - timber frame, breather membrane, insulation depth, vapour control. The difference between a summerhouse and a year-round room.
- Glazing and doors - aluminium versus timber, double versus triple, solar control coatings.
- Cladding - Siberian larch, thermally modified timber, cedar or composite, each with a different weathering story.
- Roof - EPDM, standing seam or a green roof; the last adds structural cost and considerable charm.
- Electrics - a dedicated armoured supply from the consumer unit, plus lighting, sockets and data.
- Interior finish - flooring, joinery, heating, and any plumbing if a shower or WC is included.
- Landscaping - the terrace, steps and planting that make the building belong to the garden.
Where the cheap quotes cut
Typically: a thinner insulation build-up, no vapour barrier, standard-spec glazing, a base that relies on paving slabs, and an electrical supply left to "your own electrician". None of these show on day one and all of them show by the third winter.
Worth paying for
- A proper engineered base - it is the one thing you can never revisit.
- Airtightness and ventilation together - insulation without ventilation creates condensation.
- Good glazing with solar control - comfort in July and January comes from the same line item.
- Cladding you like the aged colour of, because larch will silver whether or not you planned for it.
Getting a comparable quote
Ask every supplier for the same five things: base type, wall and roof U-values, glazing specification, whether the electrical supply from the house is included, and whether landscaping around the building is included. Once those are aligned, the prices usually converge.
For dedicated garden room specifications and model ranges, see our sister site.
Where we work
We design and build gardens, garden rooms and pergolas across Mid Sussex and the surrounding towns.
More garden rooms guides
- Oak-Framed vs Contemporary Garden Rooms: Which Suits a Sussex Home?If you are drawn to oak-framed buildings but need the performance of a contemporary garden room, this guide compares the two styles on looks, planning and longevity.
- Garden Rooms: The Complete Buyer's GuideGarden rooms range from a shed with a window to a fully insulated, year-round building. This guide explains the differences that actually matter before you spend anything.
- Do You Need Planning Permission for a Garden Room?Most garden rooms are permitted development - but the exceptions catch people out, especially in conservation areas and near listed buildings.