How to brief a builder so the quotes compare

Two quotes for the same renovation can be a long way apart. Owners read the gap as one builder being expensive. More often the two builders priced two different jobs, because each filled the gaps in the brief with their own assumptions. One included the painting, the other left it out. One allowed for mid-range tapware, the other for the cheapest on the shelf.

The fix is a written brief that every builder prices from. The government checklist builders must give you before a contract of $30,000 or more says the same: make sure the scope, materials and fixtures are the same across every quote, so you are comparing apples with apples.

What goes in the brief

1. A numbered scope. One line per piece of work, in the order the job runs: strip-out, framing, plumbing, electrical, linings, joinery, tiling, painting, flooring. A numbered line can be priced and ticked off. A paragraph of description cannot.

2. What is in and what is out. Say what you are doing yourself, what you are buying yourself, and what is not part of this job at all. Keeping the existing floor? Say so. Painting under a separate contract? Say so. Every item left unsaid is one that one builder prices and another doesn't.

3. Who owns the gaps between trades. This is where small things slip, because nobody owns them. The electrician cuts the wall and nobody has been asked to patch it. The plumber moves a waste and nobody has priced making good the floor. Write down who makes good after each trade, who coordinates the trades, and whether any trade you are hiring directly sits inside or outside the builder's job.

4. The finishes decided. Tiles, tapware, benchtop, cabinetry fronts, door hardware, light fittings, the paint system and colours. Name the product and the supplier where you know them. Where you don't, give a figure every builder must carry as a prime cost sum, so every quote carries the same number. Reading a quote explains how those sums work.

5. The unknowns named. Old houses hide things: rot behind the cladding, old wiring in the ceiling, a drain nobody has located. Ask each builder to carry a stated provisional sum for each one, or to list it as an exclusion. If you can, set the figure yourself so every quote carries the same allowance. A quote that allows nothing for the unknown looks cheaper and isn't.

6. The drawings and the documents. Attach the plans, the consent if you have one, any engineer's details, and the documents you gathered before you started. If a consent is still to be lodged, say who is lodging it. The contract will have to name who is responsible for consents, so settle it now.

7. The practical conditions. Where the trades can park, where the skip can sit, the hours you can live with, whether you are living in the house through the job, and any date the work must be finished by.

How to ask for the price

Ask for a quote, not an estimate. A quote is a price both sides are bound by once you accept it. An estimate is a best guess, and the final bill can move. Then ask for:

• the price in the same numbered form as your brief, line by line
• every PC sum, provisional sum and exclusion listed separately
• GST shown on every figure
• how long the price holds
• the rates for any extra work, and how a variation will be priced and approved
• the payment schedule they would want

Three builders pricing the same brief, in the same form, is a fair comparison. Tell each of them that others are pricing. It is fair to them, and it tells them you will read closely.

What the law adds at $30,000

Once the work is $30,000 or more including GST, the builder must give you two documents before you sign: a disclosure statement and the government checklist. On a smaller job you can ask for both and they must provide them. The disclosure statement is the builder's own account of the business: its legal form, the key contact person who will run your job if one is named, their LBP number if they hold one, the insurance the builder carries and the guarantees on offer. Read it next to the quote.

The contract itself must be in writing and dated, and it must cover, among other things: the work and the materials, who will do and supervise it, who gets the consents, the start and finish dates, the price or how it will be calculated, the payment schedule, how variations are agreed, how defects will be put right, and how disputes are resolved. Where a contract leaves out some of these, default clauses set in the regulations fill the gap. They may not suit your job, so it is better to have them written properly.

Comparing what comes back

Lay the quotes side by side, line against line. Where one is much lower on a line, ask why. The answer is usually a different product, a different method, or something missed. That conversation is where the difference between two builders shows, in how they explain their number, not in the total. The lowest price is not always the best price, and a quote far below the others is worth a second conversation to check they understood the job.

What to do next

1. Write the brief before you call anyone.
2. Send every builder the same pack: the brief, the drawings and your documents.
3. Ask for each quote in your numbered form.
4. Read the sums and exclusions before the totals.
5. Keep the brief you sent and the quote you accepted, dated, together.

Those two documents are what every later disagreement comes back to. If your property's record lives in the Archive, file them there with the invoices that follow, so in five years you can see what was asked for, what was priced and what was paid.