Renovation & Construction

Renovation work is estimated differently from new build, and the difference is not the rate — it is what you cannot see. An extension ties into a structure whose foundations, drainage and construction you discover as you dig; a refurbishment exposes wiring, plaster and floor levels that no drawing recorded. The calculators here therefore separate the measurable quantity from the allowance for what is found, rather than folding both into one figure.

Where a page needs a market rate it asks you for one instead of supplying it. A national average per square metre varies by a factor of four between regions and moves every quarter, and budgeting against one is how projects run out of money. What these tools contribute is the structure most estimates get wrong: the elements that are always forgotten, the professional fees, and the contingency applied in the right order.