When the client wants to buy their own materials

You can say yes, as long as the contract says who supplies what, who's responsible when it's wrong or late, and that your warranty covers your work, not their materials. Without that, you end up owning problems you didn't cause.

One contractor asked how others deal with homeowners who insist on buying their own materials, when markup on materials is part of how he makes a living. A landscaper described the other half: the homeowner bought the wrong materials and then blamed the crew when the result didn't look right.

The real costs

Margin. If your price assumed a markup on materials, owner-supplied materials cut your pay. Reprice the labor honestly instead of pretending it doesn't matter.
Time. Wrong items, short counts and late deliveries stop the crew. Somebody pays for the idle day.
Blame. When the tile cracks, the client sees your installation and forgets who bought the tile.

What to put in writing

A list of who supplies each item.
That the client's items must be on site by a date, and that late or wrong items move the finish date and may add cost.
That you'll check what arrives and tell them the same day if it's wrong.
That your warranty covers your workmanship, and the manufacturer's warranty covers their materials.
Whether a handling fee applies, if you charge one.

If something arrives wrong, photograph it and tell the client before you install it. If they want it installed anyway, get that decision in writing as a $0 change.

What to say when they ask

Keep it about the price and who carries the risk. Something like: "Sure. If I supply the tile, the job is $14,200, and if it cracks I deal with it. If you buy it, it's $12,900, I'll set it, and I'll check every box when it arrives. Anything wrong with the tile itself goes back to the store or the manufacturer. Your call." Most clients appreciate the choice. Some pick you supplying it once they hear who handles a bad batch.

If they buy it, ask for the exact product and quantity before they order, and add your usual waste allowance. Owner-bought orders run short more often than yours do, and a short order on a discontinued tile can stop a job for weeks.

Who supplied what, on the record

In Everkept the job says who supplies each item and what each stage must meet. If the client's materials arrive wrong and they want them used anyway, that's a change they agree to, so the record shows whose choice it was.

Start a job

This is general information, not legal advice. States differ on what a home improvement contract and its changes must contain. Check with your state’s contractor licensing board or an attorney.