Owner-supplied materials and fittings: who carries the risk

Clients often want to buy the tapware, the light fittings, the appliances or the stone benchtop themselves. Some of them have found a better price online, some want a particular look, and some are simply trying to keep the total under control. The builder is usually happy to save the money on the client’s side, and the item goes onto the job with a short note that the client has bought it. That short note is where the risk is most often left unallocated.

The question this article answers is simple to ask and harder to settle on a live job. When the client supplies the material or fitting, who carries the risk if it is wrong, late, incompatible with the design or the cause of a defect later on? The answer depends on the contract and on what the builder did or did not say at the time, not on who paid for the item. The sections below set out the mechanism, so that a builder can reason about a supplied item that the contract never anticipated.

Nothing in this article is legal advice, and it does not replace reading the contract that governs your job. It is a working explanation of where the risk tends to land, and what to put in writing so that the answer is not a dispute at the end of the job.

What changes when the client supplies the item

Ownership of the item changes hands at purchase, but responsibility for the building work does not. The builder still installs the product into a building that has to meet the requirements that apply to it, and the builder still delivers the workmanship the contract promises. Supplying the product moves the purchase, and usually the product warranty, to the client. It does not move the obligation to install competently or to tell the client when the product will not work in the place it is going.

This is the point most builders miss. The client may have bought the item from a supplier who is responsible for the product itself, if it fails in normal use. The builder is responsible for the installation and for the surrounding work. When the two interact, as they do with a waterproofing product, a sealed window system or a heavy stone benchtop fixed to a light frame, the defect rarely stays in one column. The product fails, but the water gets in through the builder’s junction, and the question becomes whose work caused the damage.

The contract decides first

Start with the written contract. The NSW Government’s guidance on contracts for home building work is the official reference for what a written contract should cover, and the contract for your job should say how client-supplied materials and fittings are handled. Look for the clauses that deal with supply, with the builder’s responsibility for materials, with variations and with what happens when an item is delayed. Where the contract is silent on a point, the default position is harder to argue than most builders expect, so the safest course is to settle the point in writing before work starts.

A contract that says nothing about client-supplied items is not a neutral document. It leaves the builder to argue, after the event, that the client carried the risk of an item they chose. That argument is easier to win when there is a dated email or a signed schedule that records the client’s choice and the builder’s warning about it. Without that record it becomes a question of recollection, and the party who has to pay for the remedial work is usually the one holding the site.

The sequence below shows where the decisions are made on a supplied item, from the moment the client chooses it to the handover. Most of the protection is built in the first two stages, which is why it is so much cheaper to settle the allocation early.

Compliance stays with the builder

A supplied item still has to meet the requirements that apply to the building. A product that is not suitable for the location, a fixing that is not rated for the load, or a window that does not meet the energy or safety requirements of the job can make the whole job non-compliant, whoever bought it. The building’s compliance is the builder’s job to protect when the builder installs the product. The client can decide to buy the item, but the builder should not install an item that the builder knows, or ought to know, will not meet the requirement.

The practical step is to check the product against the design and the requirements before it is fixed in place, and to say so in writing if there is a concern. A short note that says the builder has reviewed the product against the design and believes it may not be suitable for a particular location, together with what the builder recommends instead, is a record that protects the builder. A builder who installs a product without raising a concern, and whose concern would have been obvious on a check, is in a very different position from one who raised it and was overruled.

Be careful with the words. Many products are suitable for one location and not another, and the product data sheet is the document to read, not the sales description. Where a product is sold as suitable for a wider range of uses than the design allows, that gap is exactly where the warning belongs.

Delay: when the item arrives late, or not at all

Client-supplied items are a common cause of programme delay, and the delay is rarely the builder’s fault. A window package that was ordered too late, a fitting that arrives with the wrong finish, or a stone benchtop that does not fit the template all push the trade sequence back. The consequences fall on the builder through the trades booked around the item, the crew standing idle and the extended site costs, while the client often sees the delay as the builder’s failure.

The protection is to put the dates in the programme and to tie them to the client’s obligations. Agree the date by which the item must be on site, the date it must be confirmed, and what happens if it is not. Record the delay as it happens, with the messages that show when the client was told and when the item was expected. Where the contract provides for an extension of time for delays caused by the client, the record is what lets the builder use it. Without the record, the same delay becomes a dispute about who was late.

Building Commission NSW has published an article on rising fuel costs for trades, which deals with contracts, insurance and compliance together. Cost pressure on a job tends to make both sides look for savings in the supply chain, and that is when client-supplied items come into the job late and without the paperwork to match. It is worth reading the article alongside the contract before you accept a client-supplied item in a tight programme.

Defects that trace back to a supplied product

When a defect appears, the first question is what caused it. A seal that fails because the sealant was not compatible with the substrate is the builder’s failure. A seal that fails because the product itself was defective is the supplier’s failure, and the builder is not responsible for the product. The third possibility is the most common: the product was fine, but the builder installed it in a way the manufacturer did not allow, or in a location the product data sheet does not cover.

The Building Defects Library published by Building Commission NSW is a useful reference for describing what a defect looks like, and it helps the builder and the client talk about the same thing. The classification of the defect matters, because it affects how seriously the remedy is taken. Waterproofing problems, for example, could be classified as a major defect, and a supplied membrane that fails in a wet area is a case where that classification may apply. The distinction is covered in major and minor defects in NSW.

Keep the installation records for every supplied product. The photograph of the substrate before it was covered, the batch or serial number, the fixing method and the manufacturer’s instructions as they were on the day are the evidence that separates a product failure from a workmanship failure. Without them the builder is arguing from memory, and memory is rarely kind to the party who has to prove a negative.

Warranties and what a supplied product does to them

The warranty on a client-supplied product usually belongs to the client, and it runs between the client and the manufacturer or retailer. The builder’s own obligations sit alongside that, not inside it. The builder may still owe the client a remedy for defective workmanship, and the client may still expect the builder to deal with a failure the client has already taken up with the supplier. The two processes can run in parallel, and the builder should not assume that a manufacturer’s warranty removes the builder’s exposure.

Where the builder is asked to deal with a warranty claim for a product the builder did not supply, the builder should make the scope clear. Say what the builder will do, such as inspecting the installation and reporting on whether it was done in line with the manufacturer’s instructions, and what the builder will not do, such as accepting responsibility for the product. A short written response protects both parties and stops a goodwill favour becoming an open-ended obligation.

Writing the allocation into the job

The allocation is best settled in a single schedule that sits with the contract. List each client-supplied item, the date it is due, the person responsible for confirming its suitability, the warning the builder has given, and the client’s acknowledgement of that warning. Where the client has chosen an item against the builder’s advice, the schedule should say so in plain words. That is not an attempt to shift every risk to the client. It is a record of who decided what, and why.

Before any client-supplied item is agreed, run through the checks below. If one of them cannot be ticked, the item is not ready to be accepted onto the job.

Treat variations for supplied items the same way as any other variation. If the client wants a change that affects the installation, such as a different fixing system that the builder did not allow for, the change should be documented before the work is done, with the effect on time and cost stated. A verbal agreement to absorb the cost of a change to a client-supplied item is the kind of concession that becomes a precedent on the next job.

Worked example: a builder in regional New South Wales

Consider a builder in regional New South Wales who agreed to install a set of client-supplied sliding doors on an extension. The client bought them online, and the builder raised a concern about the frame size against the opening, which the client waved away because the supplier had confirmed the measurements. The doors arrived with a frame that was slightly out of square for the opening, and the installation took longer than planned. The builder completed the installation and the client was happy at handover.

Some months later the doors began to leak at the head during heavy rain, and the client blamed the builder. The builder’s file had a dated email with the concern, the client’s reply and a photograph of the frame before installation. The builder was able to show that the installation followed the manufacturer’s fixing method, that the leak traced to a frame that was not square, and that the concern had been raised in writing before work began. The conversation moved from whether the builder was responsible to what the builder would do to help, and the builder offered to investigate the frame with the supplier at the client’s cost. That is a very different outcome from a builder with no record at all.

The lesson is not that the builder should refuse client-supplied items. It is that a concern raised early, in writing and tied to the design, changes the question from whose fault it is to what the remedy is.

Where to check the current position

The rules on contracts, compliance and defects change, and the examples in this article describe the mechanism, not the current requirement. Check the NSW Government guidance on contracts for home building work before you finalise a contract that includes client-supplied items. Check the Building Defects Library when you need to describe a defect accurately. Where a question turns on the specific requirement for a product, the product data sheet, the design documents and the relevant official requirement are the sources to rely on, not a summary of them.

If a dispute does arise, get advice from a solicitor who works with building contracts before you make any offer or admission. The record you have built while the job was underway is usually what decides the outcome, and it is far cheaper to build it at the start than to rebuild it afterwards. The broader picture of how defect responsibility runs after handover is covered in the defect liability period in NSW.

The wider obligations that sit around a licensed builder, including the continuing professional development that keeps a licence current, are set out in the PointCPD guide to how NSW builder CPD works.

Whatever the item, the rule is the same. Settle the allocation before the item goes in, write the warning down, and keep the record that shows who decided what.

Questions builders ask

• Contracts
• Defects
• Materials

Published 26 October 2026. General information for builders, not legal, financial or engineering advice for a specific job. Check current requirements with the relevant regulator or standard before relying on them.