SiteKiln gives you plain-English information, not legal advice. It's aimed at small UK construction businesses and sole traders. Laws change and every job is different, so speak to a solicitor or adviser before you rely on this for a real dispute.
They've bought the entire patio from Amazon. Half of it's wrong, none of it's on site, and they still want you to start Monday. Welcome to customer-supplied materials -- the single biggest source of diary chaos, blame-shifting, and unpaid extra time in domestic work. This guide covers where you stand legally, how to protect yourself on quotes, and what to say when the conversation gets awkward.
1. Why customer-supplied materials wreck schedules
You have probably heard the pitch: "We'll save money by buying the materials ourselves. You just do the fitting." It sounds reasonable. In practice, it goes wrong in the same ways every time.
The Amazon bathroom problem
The customer orders tiles, a basin, taps, and a shower tray from three different websites. The tiles arrive a week late. The basin is the wrong size. The shower tray is a cheap brand that does not sit level. The taps need adapters that were not included.
You are booked for five days. Day one arrives and half the materials are missing. You cannot start the tiling because the shower tray is not in yet. You cannot fit the basin because it does not match the unit they bought from somewhere else. Your five days turn into eight, spread over three weeks, and the customer expects you to absorb the extra time because "it's not that big a deal."
It is a big deal. It is your income.
The common problems
- Late delivery. The materials are not on site when you need them. You either wait (unpaid) or rearrange your diary.
- Wrong specification. Wrong size, wrong finish, wrong grade. You spot it on day one and now everyone is scrambling.
- Poor quality. Cheap materials take longer to work with. Budget tiles chip easier, budget worktops need more prep, budget paving slabs are not consistent thickness.
- Incomplete orders. Fixings, trims, adhesives, sealants -- the customer buys the main product but not the bits that go with it.
- No returns process. When you supply materials and something is wrong, you swap it out through your merchant. When the customer supplies and it is wrong, they have to deal with the retailer. That takes days or weeks. Your diary is wrecked either way.
2. The legal split -- your work vs their kit
This is the bit that matters most and the bit most trades do not know. The Consumer Rights Act 2015 (CRA 2015) treats goods and services differently, and who supplied the materials changes everything about who is responsible for what.
When you supply goods and services
If you supply the materials and do the fitting, the customer has rights under both the goods provisions and the services provisions of the CRA 2015:
- Section 9 -- goods must be of satisfactory quality.
- Section 10 -- goods must be fit for a particular purpose (if the customer told you what they needed them for).
- Section 11 -- goods must match their description.
- Section 49 -- services must be performed with reasonable care and skill.
You are on the hook for the lot. If the tiles crack because they are poor quality and you supplied them, that is your problem. If the tiles crack because you fitted them badly, that is also your problem.
When the customer supplies the goods
If the customer buys the materials and you just do the installation, the contract is a services contract only. You are responsible under:
- Section 49 -- reasonable care and skill in your workmanship.
- Section 50 -- any information you gave them about the service (e.g. if you said "those tiles will be fine for a wet room" and they were not).
- Section 51 -- reasonable price (if no price was agreed).
- Section 52 -- reasonable time (if no timescale was agreed).
You are NOT responsible for the quality, fitness for purpose, or description of the goods themselves. That is between the customer and whoever sold them the materials.
Business Companion (the government-backed trading standards resource) puts it clearly: "If a consumer engages you to install goods for them which someone else supplied, this is a services contract, not a goods contract."
In plain English: If they buy cheap tiles and the cheap tiles fail, that is between them and the tile shop. If you fit those tiles badly, that is on you. The line is your workmanship, not their product.
3. The 6-month rule -- and why it does not apply to their stuff
Under Section 19 of the CRA 2015, if goods you supplied develop a fault within the first six months, it is presumed the fault was there from the start (the "reverse burden of proof"). The customer does not have to prove the goods were faulty -- you have to prove they were not.
This is a powerful consumer protection. But it only applies to goods you supplied under a goods contract or a mixed goods-and-services contract.
If the customer supplied the goods themselves, Section 19 does not apply to those goods. If their cheap shower tray cracks after four months, they cannot use the 6-month reverse burden against you. They would need to go after the retailer who sold it to them.
Your workmanship is a separate question. If your tiling is falling off after four months, the customer can still come after you under Section 49 (reasonable care and skill). But the product failure itself is not your liability.
Tip: Citizens Advice tells consumers: if a product is faulty and it was supplied by someone else, complain to the retailer. If the installation was poor, go after the trader who did the work. This is the distinction you need your customers to understand before you start.
4. How to write it into your quotes
You need three things on every quote where the customer is supplying materials: a clear statement of who is supplying what, a delivery deadline, and a clause covering what happens when things go wrong.
Example clause 1: Responsibility split (copy-paste ready)
"The customer is supplying the following materials: [list].
We are responsible for the quality of our workmanship only. We are not responsible for the quality, suitability, or fitness for purpose of customer-supplied materials. If customer-supplied materials are faulty, incorrect, or unsuitable, any remedial work, refitting, or additional labour required will be charged at our standard day rate of £[X].
Our guarantee covers our workmanship for [X months/years]. It does not cover failures caused by defective, substandard, or incorrectly specified customer-supplied materials."
Example clause 2: Delivery and readiness (copy-paste ready)
"All customer-supplied materials must be delivered to site, checked, and approved at least [3/5] working days before the agreed start date. Materials must be complete, including all fixings, trims, adhesives, and ancillary items required for installation.
If materials are not on site, are incomplete, or are found to be incorrect specification on our pre-start check, we reserve the right to: (a) delay the start date until materials are ready, or (b) stand down and return on a new date, with a recall charge of £[X] to cover wasted travel and rearranged diary time.
Any waiting time on site due to missing or incomplete customer-supplied materials will be charged at our standard hourly/day rate."
Example clause 3: The quality warning (copy-paste ready)
"We are happy to work with customer-supplied materials. However, please be aware that lower-specification products may require additional preparation time, may not achieve the same finish as professional-grade alternatives, and may have a shorter lifespan. If we believe any customer-supplied material is unsuitable or likely to fail, we will flag this before starting work. If you choose to proceed, we will note this on the job record and our workmanship guarantee will not cover failures attributable to the materials."
5. Scripts for common conversations
Scenario 1: "Can't you just start with what's here?"
Half the materials are on site. The customer wants you to crack on and work around the gaps.
"I totally understand you want to get moving -- so do I. The problem is, if I start fitting around missing bits, I'm going to have to come back, rework sections, and it'll end up taking longer and costing more than if we just wait until everything's here. Let me check what's missing and we'll get a delivery date nailed down. Once it's all on site, I'll come back and do a pre-start check, and then we're good to go. I'd rather do it once and do it right."
Scenario 2: "The tiles have cracked -- you need to come back and redo them"
Customer-supplied tiles have failed. The customer thinks it is your fault.
"Sorry to hear about the tiles. I'll come and have a look to see what's happened. But just so you know upfront -- the tiles were supplied by you, so if it turns out they're a product fault rather than a fitting issue, that's something you'd need to take up with the retailer. If I fitted them wrong, that's obviously on me and I'll sort it out. But if the product itself is defective, the retailer is the one who's legally responsible under the Consumer Rights Act. Let's take a look first and we'll work out what's going on."
Scenario 3: "We want to supply our own materials to save money"
The customer announces they want to buy everything themselves.
"Absolutely fine, lots of customers do that. I just need to make sure we're both clear on a few things before we start. I'll put a note on the quote confirming which materials you're supplying and which I'm supplying. Your stuff needs to be on site and checked [3/5] days before I start. If anything's wrong spec, short, or late, I might need to push the start date or charge for waiting time. And my guarantee covers my workmanship -- if a product you've supplied turns out to be faulty, that's between you and the supplier. I'm not trying to put you off. I just want us both to know where we stand so there are no surprises."
6. Insurance -- what to check with your broker
Customer-supplied materials create a few insurance grey areas. Here is what to ask your broker or insurer.
Public liability (PL)
Your PL insurance covers damage caused by your work, regardless of who supplied the materials. If you accidentally crack a customer-supplied basin while fitting it, your PL should cover the replacement cost. Check your policy wording -- most standard trade PL policies cover "damage to property being worked upon" but some have exclusions or sub-limits.
Product liability
Product liability covers claims arising from products you supplied that turn out to be defective. If the customer supplied the product, product liability is less relevant to you -- the liability sits with the manufacturer or retailer. However, if you recommended or specified the product (even though the customer bought it), your professional indemnity cover becomes relevant.
Professional indemnity (PI)
If you are specifying or recommending products -- "get these tiles, they'll be fine for a wet room" -- and the product turns out to be unsuitable, the customer could argue you gave negligent advice. PI insurance covers this. If you regularly advise on product selection, even when the customer is buying, make sure you have PI cover.
What to tell your broker
- "I regularly install customer-supplied materials. Is my PL cover adequate for accidental damage to their goods while I'm working on them?"
- "If I recommend a product and the customer buys it themselves, am I covered under PI if it turns out to be unsuitable?"
- "Is there anything in my policy that excludes or limits cover when the customer supplies materials?"
7. Pricing for the extra faff
Customer-supplied materials almost always take longer than trade-supplied. Budget for it.
Why it costs more
- Pre-start checking. You need to inspect what they have bought, check quantities, check specs. That is at least an hour on a decent-sized job.
- Quality issues. Cheaper products are less consistent. Tiles vary in size. Timber varies in straightness. Paving slabs vary in thickness. Everything takes longer to prep and fit.
- Waiting time. When something is missing or wrong, you are standing around or going home. Either way, you are not earning.
- No trade discount. When you supply, you buy at trade price and mark up. When they supply, you lose that margin entirely. You need to recover it somewhere.
- Callback risk. If a cheap product fails and the customer argues about whose fault it is, you might end up doing a site visit or partial refit before it gets resolved. That is unpaid time even if you are in the right.
How to price it
- Add a materials handling charge -- a flat fee (£50-150 depending on job size) for the pre-start inspection, checking deliveries, and coordinating with the customer on what is missing.
- Increase your day rate or quote by 10-15% to account for slower working with potentially lower-grade materials.
- Include a waiting time clause -- your standard hourly or half-day rate for any time spent on site unable to work because of missing or incorrect customer-supplied materials.
- Be transparent about it. Tell the customer: "When I supply materials, the price includes my trade discount and I can swap things out same-day if there's a problem. When you supply, I lose that flexibility, so the labour rate is slightly higher to account for the extra time it usually takes."
Tip: Some trades quote two versions: one with materials included (trade-supplied), one without (customer-supplied, higher labour rate). Let the customer see the numbers. Most of the time, the difference is small enough that they choose the trade-supplied option and save themselves the hassle.
8. Who to contact
- Citizens Advice -- free advice on consumer rights and trader obligations: 0800 144 8848 (England), citizensadvice.org.uk
- Your insurer or broker -- ask the specific questions in Section 6. Do it before a claim, not during one.
- Business Companion -- government-backed trading standards guidance for businesses. Free, plain English, and covers the goods-vs-services split clearly: businesscompanion.info
- A solicitor -- if a customer is pursuing you for a product failure on materials they supplied and the amount is significant. A 30-minute consultation can confirm whether their claim has legs.
9. Related SiteKiln guides
material-pricing-and-markup-- how to price materials properly, including markup14.8-materials-who-supplies-who-pays-- the full breakdown of who supplies what and who payscustomer-cancellations-deposits-- deposits, cancellation terms, and what you can keep6-1-public-liability-insurance-- what PL covers and what it does notdeposits-vs-booking-fees-- structuring payments to protect your position
10. What to do next
- Add a customer-supplied materials clause to your quote template today. Use the example wording in Section 4. It takes five minutes and it will save you hours of arguments.
- Set a delivery deadline on every job. Materials on site X days before start, or the date moves. Put it in writing every single time.
- Talk to your insurer. Ask the three questions in Section 6 before you need to make a claim. Know where you stand now.
- Price the extra time in. If you are not charging for the faff that comes with customer-supplied materials, you are working for free. Add the handling charge and adjust your labour rate.
- Keep a pre-start checklist. Photograph what arrives on site, note what is missing or wrong spec, and send it to the customer in writing before you start. That record protects you if things go sideways later.
11. Sources
- Consumer Rights Act 2015 -- Part 1 Chapter 2 (goods: Sections 9, 10, 11), Part 1 Chapter 4 (services: Sections 49, 50, 51, 52), Section 19 (6-month reverse burden of proof for goods). legislation.gov.uk/ukpga/2015/15/contents
- Business Companion -- "Supply of services" guidance (government-backed trading standards resource): businesscompanion.info
- Citizens Advice -- "If you have a problem with a service" (consumer guidance on trader vs retailer responsibility): citizensadvice.org.uk
- Association of British Insurers (ABI) -- guidance on trade insurance and product vs public liability distinctions: abi.org.uk
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