Materials and supplies

Yes

Materials bought specifically for jobs are fully deductible as a business expense in the tax year you incur them. This covers anything you purchase to do the work: pipe, cable, fittings, timber, fixings, grout, paint, etc.

Common questions

Can I claim materials I buy for jobs?

Yes. Materials purchased for specific jobs are a direct business expense. Keep supplier invoices and receipts.

I bought stock in advance and haven't used it yet. Can I claim it now?

Technically, materials you have not used yet at year-end should be listed as unused stock (shown as closing stock in your accounts) and not deducted until used. For small amounts with fast turnover, HMRC usually accepts claiming them in the year you bought them.

Watch out for

Charging a client for materials at a mark-up: the cost is still deductible, and the mark-up forms part of your taxable income. Example: £2,000 of materials recharged at £2,400 means a £2,000 expense and £2,400 of income; the £400 margin is taxed as profit.
Materials taken for a project on your own home are not a business cost. If you already claimed them, adjust for the amount taken.
Wastage and offcuts on a job are part of the job's material cost. No adjustment needed for normal waste.

Common mistakes

Netting materials against the client's payment instead of recording the cost and the income separately. The profit is the same but it understates turnover.
Claiming materials used on your own home.
On traditional accounting, forgetting the closing stock adjustment for a big year-end materials pile.

Cash basis vs traditional accounting

On cash basis, deduct materials when you pay for them, even if the job is invoiced later. On traditional accounting, materials unused at year end sit as closing stock and are deducted when used.