The last two lines of an estimate decide whether a job produces profit or only turnover — and they are the two most often guessed at.
What overheads cover
LBN 501-17 defines overheads as the additional costs of setting up and running the site, organising and managing the works, occupational safety and insurance, and other costs tied to carrying out the job. In a small firm that means temporary fencing, a skip, power and water on site, your own management hours, travel and fuel, PPE, insurance, accounting — and warranty call-outs after handover.
Overheads are not profit. Charging 15% overheads and 0% profit means working at cost.
Typical percentages
The regulation does not set the numbers, it only requires them to be shown as a percentage of direct costs. In practice: overheads 8–15%, profit 10–20%, plus a 5–10% contingency on renovation work. Both percentages are calculated from direct costs — not one on top of the other.
A worked example
Facade insulation with €9,666 of direct costs: 12% overheads is €1,159.92, 10% profit is €966.60, giving €11,792.52 net and €14,268.95 with 21% VAT.
See also preparing an estimate and LBN 501-17.