Buying the parts is work. Collecting them, fronting the cash and guaranteeing them is more work. Charging for it is not cheeky — it is the job.
31 August 2026 · 5 min read
Ask ten tradespeople what they add to materials and you will get ten answers, several of them “nothing, I just pass it on at cost”. That last one is the expensive answer, and it is far more common than it should be.
It is not profit on the copper. It is the trip to the merchant, the queue, the fuel, the hour spent working out which part fits, the money sitting on your card until the invoice clears, and the fact that if the part fails in six months you are the one going back. Supplying materials carries cost and risk. Cost and risk get priced.
Most trades work on a percentage added to trade price, often higher on small fiddly items and lower on big-ticket kit where a flat percentage would look absurd on the quote. A £4 fitting and a £2,400 boiler should not be treated the same way. Pick your own bands, write them down, and apply them consistently rather than deciding afresh on every job at ten at night.
Adding 20% to your cost does not give you a 20% margin — the maths runs the other way, and the gap is where a lot of quiet underpricing lives. Run your figures through the profit margin calculator before you settle on a number, so you know what you are actually keeping.
You have two options and both are legitimate: itemise materials at your supply price, or roll everything into a single supply-and-fit figure. The one thing to avoid is showing the customer the trade invoice and then adding a visible percentage on top — that invites a conversation about your margins that has nothing to do with the work. Whichever you choose, a clean branded PDF makes it look deliberate. GraftG builds one from a plain-English message such as “Quote for Mrs Hall, replace consumer unit, 1 day labour, £310 parts”; see the quotes guide.
Plenty will, especially on kitchens and bathrooms. Say yes if you want the work, but be explicit in writing that you do not warrant parts you did not supply, and that waiting for a missing item is chargeable time. Then price your labour properly, because you have just lost the materials contribution.
Track materials against jobs as you buy them — “Materials: £45 copper pipe” on the live job — so the finished job shows labour, materials and the real total rather than a guess. Over a few months that is the evidence that tells you whether your bands are right. More on that in busy but broke.
Yes, it is standard practice across the UK trades. The uplift covers sourcing, collection, cash flow and the warranty risk you carry on anything you supply. Passing materials on at exactly trade price means doing all of that for free.
Either itemising materials at your supply price or quoting one supply-and-fit figure is fine. What causes arguments is showing a trade invoice alongside a visible percentage, because it turns a price conversation into a conversation about your margin.
Agree it in writing before you start, make clear you cannot warrant parts you did not supply, and state that time lost to wrong or missing items is chargeable. Price your labour on the basis that the materials contribution has gone.
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