When a job comes in under quote it is usually because someone bought well. When a job comes in over quote it is almost never one dramatic overspend. It is three ordinary things that were never priced.
1. Waste is a quantity, not an attitude
Tiles get cut. Blocks break. Cement hardens in a bag left out overnight. Timber is bought in stock lengths and used in awkward ones. None of this is carelessness; it is the physical reality of the trade, and it belongs in the quantity.
| Material | Typical allowance | Why |
|---|---|---|
| Floor tiles 60×60 | 8–10% | cutting at edges, breakage, pattern matching |
| Wall tiles | 10% | more cuts around fittings |
| Sandcrete blocks | 5% | transit and handling breakage |
| Cement | 3–5% | spillage, part bags, hardened stock |
| Roofing sheets | 5–8% | overlaps and end cuts |
| Reinforcement bar | 3–5% | off-cuts and laps |
| Paint | 5% | roller loss, touch-ups, colour matching |
On a 180 m² tiling job, forgetting a 10% allowance means buying 18 m² of tile you did not price. At GHS 132 per square metre that is about GHS 2,400 — on one trade, on one house.
2. Haulage is priced in trips, not kilometres
Sand, chippings, laterite and blocks arrive by the trip, and the trip price varies with distance, access and how badly the driver wants the work that week. A plot in Tantra Hills with a steep approach is not the same delivery as a plot on the Spintex road, and pretending otherwise is a decision to absorb the difference.
- Count trips explicitly, as line items, with the vehicle named.
- Round up. There is no half trip.
- Add a mobilisation trip for tools, hoarding and the first materials.
- If access is poor, price the head-carry from the road. Labourers moving 500 blocks by hand is a real cost.
3. Site loss is a security cost, not bad luck
Materials disappear from unsecured sites. The industry answer is a watchman, hoarding and a lockable store — all of which cost money that has to be in the preliminaries. A contractor who prices no preliminaries has agreed to fund site security out of profit.
What good practice looks like
Put waste in the quantity, not in a mental buffer. Put haulage on its own lines so a client can see it. Put site setup in preliminaries and price it honestly. Every one of these is easier to defend to a client than an unexplained round number at the bottom of a page — and far easier than going back mid-job to ask for more.