How it works
1Identify your build route from the four options Your level of involvement in the project will influence the build costs. For simplicity, the four most common build routes have been identified below: DIY Build + Subbies Route A: Building on a largely DIY basis, substituting around 30% of labour costs with DIY, and employing help with the rest of the building work. Materials purchased directly. Build Route B: Subbies Building using tradespeople hired directly — you will be project managing, but there is minimal DIY involvement. Most or all materials purchased directly. Build Route C: Builders/subbies Building using a main contractor or package supplier to complete the structure to a weathertight stage, with the remaining work undertaken by subcontractors and most materials purchased by self-builder direct from suppliers. Build Route D: Main contractor Building using a main contractor. Building in this way requires the least involvement from the self-builder.
2Identify your expected level of specification The standard of specification that you choose will have an enormous influence on your build cost. For estimating purposes, three general categories of quality have been identified: Standard: This represents a basic build quality equivalent to that offered by most speculative developers. A house may include standard softwood joinery, studwork partitions, a contract kitchen, basic sanitaryware and radiator central heating. Good: This is equivalent to that offered by quality developers. Features may include high-end off-theshelf softwood joinery, blockwork partition walls, contract quality kitchen and sanitaryware and underfloor heating (UFH) downstairs. Excellent: A very high standard. This house may include hardwood joinery, blockwork partition walls, a bespoke kitchen and quality sanitaryware, and UFH, for instance.
3Multiply figure by the your house size We have used gross internal floor area as a measure (it’s the most common in the industry). It’s the area of a building measured to the internal face of each perimeter wall for each floor level. It includes areas occupied by internal walls and partitions.