How to Compare Renovation Quotes Before You Sign Anything

You have three quotes for the same bathroom, and they come in at $18,000, $24,500 and $31,000. Nothing on the paperwork explains a $13,000 gap, and the cheapest builder is the one who returned your call fastest. Learning to compare renovation quotes properly is how you stop that spread from turning into a variation bill halfway through the job.

The short version: most of the difference between quotes is not profit margin. It is scope that one builder included and another left out, allowances that are set too low, and assumptions nobody wrote down. Here is how to line them up honestly.

Why renovation quotes are so hard to compare

Builders do not quote from the same template. One will itemise demolition, waterproofing, tiling and fit off as separate lines. Another will write "bathroom renovation as discussed, $24,500" and nothing else. Neither is necessarily dishonest, but the second gives you nothing to check.

The usual traps are:

• Prime cost and provisional sum items. A PC allowance of $800 for a vanity looks fine until you pick one for $1,600. The difference, plus margin, lands on you.
• Excluded trades. Electrical, plumbing rough in or plastering may be "by owner" in one quote and included in another.
• Unwritten assumptions. "Subject to site conditions" can cover rotten floor joists, asbestos sheeting or a slab that needs regrading.
• Different finish levels. Floor to ceiling tiles versus a 1.2 metre wet wall can be a $3,000 swing on its own.

Step by step: how to compare renovation quotes

Set aside an evening, a spreadsheet and the three quotes. This process takes about 90 minutes for a single room renovation.

1. Write your own scope first. Before comparing anything, list what you asked for: rooms, fixtures, finishes, and who supplies what. Send the same written scope to every builder. If you skipped this step, send it now and ask them to requote against it.
2. Build a comparison table. Rows are scope items, columns are builders. Mark each cell with the price, "included" with no price, or "excluded".
3. Total the allowances. Add up every PC and provisional sum per quote and compare them with real prices from a supplier. Low allowances are the most common way a cheap quote becomes an expensive job.
4. Adjust to a like for like total. For each excluded item, add a realistic cost. For each low allowance, add the shortfall. Now compare.
5. Check the paperwork. Licence number, insurance certificate, home warranty insurance where the job value requires it, and a written contract with a payment schedule.

In my experience the adjusted totals usually land much closer together than the original numbers. That $18,000 quote often becomes $25,000 once the excluded electrical and the thin tile allowance are filled in.

An example comparison

In this example, A and B are effectively the same price, and B carries less risk because more is written down. C is the genuine outlier, and the question becomes whether its extras are worth $6,500.

Questions to ask every builder before you decide

Call each builder after your table is done. Their answers matter as much as the numbers.

• What happens if you find rot, asbestos or water damage once the old tiles are off? How is that priced?
• Who does the waterproofing, and do I get a certificate? Our checklist on bathroom waterproofing checks before tiling covers what to ask for.
• What is the deposit, and how are progress payments tied to stages?
• How long is the quote valid for, and are materials prices locked?
• When can you start, and how many jobs are you running at once?

A builder who answers these clearly and puts the answers in writing is worth a premium. One who gets vague or irritated is telling you how the variations conversation will go later.

The cheapest quote is not the one to throw out

The common advice is to discard the lowest quote automatically because it must be cutting corners. I do not agree. A low quote can come from a small operator with low overheads, a builder with a gap in their schedule, or simply better pricing on materials they buy in volume.

The right move is to normalise it first, as in the table above, and then judge it. If the adjusted figure is still well below the others, ask the builder directly how. A good answer sounds like "I do the tiling myself" or "I have a free fortnight in March". A bad answer sounds like "we will sort it out on site". Throwing out the low quote without checking can cost you the best builder in the group.

Spend where it pays back

Once your quotes are comparable, you can decide where the money should go. If the renovation is ahead of a sale, put budget into what buyers see and touch, not hidden upgrades they will never notice. The thinking in which kitchen upgrades pay you back at sale applies to bathrooms and living areas too. If you are juggling several projects, follow the right order to renovate a house so one trade does not undo another.

Before you sign, ask the chosen builder to fold everything from your comparison into the contract: the adjusted allowances, the inclusions you confirmed by phone, and how site surprises will be priced. A verbal "that is included" is worth nothing once the walls are open. If the builder resists writing down what they already told you, treat that as useful information about how disputes will be handled. Most good builders are happy to tighten the paperwork, because it protects them from scope arguments too.

Keep a 10 to 15 percent contingency on top of the adjusted quote you choose. Older houses tend to need the full 15.

Frequently asked questions

How many quotes should I get for a renovation?

Three quotes is the usual standard for a single room renovation. Fewer leaves you without a reference point, and more than four rarely adds new information while using up a lot of builders' goodwill. For larger whole house jobs, three detailed quotes are still enough if they are against the same written scope.

What should be included in a renovation quote?

A good quote lists each stage or trade, every prime cost and provisional sum allowance, what is excluded, the payment schedule, and how long the price is valid. It should also show the builder's licence number and insurance details.

Why do renovation quotes vary so much?

Most of the gap comes from scope differences, excluded trades and low allowances rather than profit. Once you adjust quotes to the same scope, they usually sit much closer together, which makes the real differences easier to see.