How does JengaCost price a house?

A JengaCost estimate is a measured bill, not a cost per square metre multiplied by the floor area. For each design the app works out:

1. Quantities from the drawn model: excavation and concrete in the foundations, walling by area with door and window openings deducted, ring beams and slabs, the roof by its true sloped area, every door and window, plaster, floors, ceilings, paint, wet rooms and electrical points.
2. Rates from the rate library: each one dated, with a low, typical and high figure. Economy, standard and premium finishes use the low, typical and high rates.
3. The county adjustment: materials and labour cost differently in Turkana than in Kiambu, so baseline rates are adjusted to the county you pick.
4. Approvals, levies and transport: an allowance for county approval fees, the NCA levy, getting materials to site, and temporary water and power.

Anything the library has no rate for is listed as not priced rather than guessed. You can see every line, change any rate, and save the bill as a project.