What is a BOQ and how to read it before signing a house construction contract

A BOQ (Bill of Quantities) is a document that breaks the whole house build into line items with the quantity, unit, material price and labor cost of each — simply put, an "advance receipt" for the whole house

The structure of a good BOQ

A standard BOQ is divided into major sections in construction order: site preparation, piles and footings, structure, roof, walls and plaster, floors, ceilings, doors and windows, painting, electrical, plumbing and sanitary, and sanitary ware. Each line needs 4 numbers: quantity × material unit price + quantity × labor unit price

What you must read carefully

• "Lump sum" (LS) items — Lines with no quantities, e.g. "all electrical work, lump sum 150,000", can't be compared and often hide profit. Ask for them to be broken down point by point (number of lights, outlets, switches)
• Material specs must state brand and model — Just "granite tiles" ranges from 200 to 2,000 baht per square meter; if brand, model and size aren't fixed, the contractor can always choose the cheapest
• Waste allowance — Allowing 5–10% for breakage on materials like tiles is normal, but if you see 20–30% on every line, ask questions
• What's "not included" matters more than what is — The end of a BOQ usually has notes such as excluding land filling, electricity meters, water pumps and tanks — always add these to your budget

Use the BOQ to compare contractors

With BOQs from 2–3 contractors, don't just look at the total; compare section by section. One that's unusually cheaper in the structural section may be cutting steel or cement specs, which you can't see after the house is built. Price differences in finishing are understandable, but structure should be similar across all contractors

Bhoon Kharn has a free BOQ quotation tool, both for homeowners who want reference prices and for contractors who need to issue documents to customers. Try it under the "BOQ quotation" menu