Comparing quotes for your renovation: how to read what's actually there

01What has to be in a quote

A decent quote is more than a total on a single page. Legally, a contractor has to mention at least the following [1]:

A quote that consists of one A4 with a total amount and no further explanation? That's a red flag. Not necessarily because the contractor is unreliable, but because you can't compare what you can't read.

Prices must be unambiguous. Hidden costs are legally forbidden under Book VI of the Code of Economic Law [4].

02The four quote formats

Not every contractor builds his quote the same way. That makes comparing tricky, but it's not impossible if you know what you're looking at.

Per unit (m², linear metre, per piece)

The most transparent form. You see exactly what you're paying per square metre of floor, per linear metre of pipe, per socket. You can check the arithmetic.

Watch out for: what's not in the unit price? Sometimes transport, clean-up or connection are separate. Sometimes not mentioned at all.

Lump sum (fixed price)

One amount for the entire job. Simple and clear at first glance. But it hides what's actually included.

Always ask for a decomposition: a breakdown of the lump sum into sub-items. A good contractor has that breakdown anyway to calculate his price. If it isn't available, you can't compare.

Time and materials (hourly rate + materials)

You pay for the hours actually worked and the materials actually used. The price risk sits entirely with you as homeowner [5]. If the work takes longer than expected, you pay more.

Time and materials can make sense for work with many unknowns, like opening a wall behind which you don't know what you'll find. But for predictable work, a fixed price is better.

Be careful if a quote puts large items on "time and materials" without an indicative budget or cap. That's effectively a blank cheque.

Mixed

Some items lump-sum, others on time and materials. Common on renovations: the demolition on T&M (because nobody knows what's behind the walls), the new installation lump-sum.

This is the fairest approach for renovations with unknowns. But check carefully which items are in which format. The T&M items are where your budget can go off the rails.

03How to make quotes comparable

The comparison doesn't start at the total. It starts at the line items.

1. Everything on one line. Put all items from all quotes next to each other. One table, three columns. Per item you see immediately who mentions what.

2. Flag missing items. Compare line by line. Item X is in quote A and B, but not in C? Flag it. That doesn't mean C forgot. Maybe it's included elsewhere. But you need to ask.

3. Ask questions. For every missing item: "Is X included in your quote? If yes, where? If no, what would it cost?" This isn't distrust. This is care. A good contractor expects those questions.

4. Normalise the units. Where possible, convert everything to the same unit. If contractor A quotes per m² and contractor B quotes lump-sum, ask for the surface area and calculate the m² price. Then you're actually comparing the same amount of work.

5. Add up the missing items. Add the cost of missing items to the cheaper quotes. In practice, the cheapest quote often becomes more expensive than the middle one once you count everything.

04Items that are often missing

Some cost items appear in one quote and not the other. Those are often exactly the items that cause surprises.

Demolition work. Removing existing structures, floors, walls or installations. Sometimes included, sometimes not. Ask explicitly.

Rubble disposal. Skip costs, transport, processing costs. Can quickly add up to hundreds or even thousands of euros on a larger renovation. Often billed separately or not mentioned at all.

Pipe and chase routing. Chasing grooves in walls for pipes and cables. Electricians often mention it, but not always. Plumbers the same.

Connection to utilities. Connecting your new installation to the existing water, gas or electricity network. Sometimes this sits with the installer, sometimes not.

Inspections and certification. Electrical inspection, gas inspection, EPB reporting. Sometimes included, more often not. Budget for separate costs.

Clean-up after works. Not every contractor cleans up his site when leaving. If you expect it, put it in the contract.

Transport and hoisting. Material delivery to the floor, container lift, crane. Irrelevant on a ground floor renovation, relevant for a third-floor flat.

Unforeseen works. No quote can predict everything. Many architects and contractors advise a buffer of 10 to 15% on top of your estimated budget, especially for older homes. That buffer isn't in the quote, but it should be in your budget. A solid system for keeping your construction budget helps you protect that buffer.

05VAT: 6% or 21%?

The difference between 6% and 21% VAT on a 100,000 euro renovation is 15,000 euro. It's worth understanding properly.

The basic rule

Renovation of a home at least ten years old: 6% VAT [3]. The home has to be used mainly as a private residence and the works have to be invoiced directly to you as the end user [3].

When 21% applies

New construction is always 21%. But on renovations, 21% can also apply to specific items. Extensions above certain limits, entirely new structures inside an existing building, and since July 2025 also the supply and installation of gas or oil heating systems [3].

Mixed projects

On larger renovations it can happen that some works are invoiced at 6% and others at 21%. A new kitchen in a 30-year-old home: 6%. A completely new annex to that same home: possibly 21%.

Check whether your quote lists the correct rate per item. Since 2022, the old VAT certificate has been replaced by a standard declaration on the invoice [3]. The contractor includes the declaration, but as the homeowner you share responsibility that the conditions are met.

The trap

A quote fully calculated at 6% while part should have been 21%? That correction doesn't come from your contractor. It comes from the tax authority. And then you still pay the difference, plus a possible fine.

Not sure about the rate? Ask your contractor. A professional contractor knows exactly when which rate applies.

06Payment terms: what to watch for

How you pay is almost as important as how much you pay.

Standard pattern

A common schedule: 20 to 30% on signing the contract, interim payments tied to milestones (shell done, roof on, finishing complete), and 5 to 10% retention until handover.

Breyne Act

If the Breyne Act applies to your project (one contractor building the entire home, or buying off-plan), the advance may be no more than 5% and the payment tranches can never exceed the value of the work done [2].

Red flags

Construction loan

If you're financing through a construction loan, the payment tranches from your contractor have to match the drawdown schedule of your bank. The bank releases tranches based on progress, confirmed by your architect. If your contractor's schedule doesn't line up, you'll have liquidity problems.

Discuss this before you sign, not when the first invoice comes in.

07Questions to ask after receiving quotes

Not every question is distrust. Most are just due diligence.

"Is X included?" For every item in the list above. Demolition, rubble, pipework, inspection, clean-up.

"What if we hit Y?" Force your contractor to name his approach for unforeseen situations. "What if the pipes behind the wall are in poor shape?" Fixed price, time and materials, or a pre-agreed additional-cost scheme?

"Can you break the lump sum down?" Tests transparency. A contractor who refuses may be hiding something. Or he hasn't calculated his price properly. Both are reasons for caution.

"What's the hourly rate if work goes to time and materials?" That way you have a reference when items open up.

"What's a realistic planning?" Compare promises with what references from previous clients confirm. And don't forget to also check the financial health of your contractor before you sign.

A good contractor answers these questions without difficulty. The answers tell you more than just about the quote. They tell you what it will be like to work with that contractor.