Garden Room Cost Calculator
Get a realistic materials cost estimate for your UK garden room build
Choose your size
Build specification
Optional extras
How we calculate these costs
Our cost model is based on per-m² rates for each major component category, derived from real UK supplier pricing. We use mid-range prices — not the cheapest possible (which often compromises quality) and not premium retailer pricing.
The spec multiplier reflects both material quality and material quantity. A budget build uses thinner insulation, simpler cladding, and basic interior finishes. A premium build uses 150mm PIR wall insulation, Siberian larch or cedar cladding, and high-quality interior boarding.
The professional cost estimate assumes a typical UK contractor rate of approximately 2.75× the materials cost. This is a rough guide — actual quotes depend on location, contractor, access, and market conditions.
Want itemised shopping lists? The Build Pack includes exact quantities and supplier recommendations for every material category, for each supported build size.
Ready to build your garden room?
Get the complete DIY build pack — full plans, materials list, and step-by-step guides for £49.