Tax, CIS and Making Tax Digital for self-employed steel fixers

When Making Tax Digital starts for steel fixers

It depends on your qualifying income, not your trade. Qualifying income is the total of self-employment and property income before expenses (turnover), not profit.

Once you’re in, you send HMRC a quarterly update by 7 August, 7 November, 7 February and 7 May, then a tax return after the year ends. MTD for Income Tax does not change how tax is paid or the payment due dates.

Check your own start date and what to sort first. It’s free and takes a minute.

CIS for steel fixers

Fixing reinforcement on site is part of building the structure, so it is inside CIS, from foundations and piles to slabs, walls, bridges and roads. HMRC’s A to Z of construction work has no separate entry for steel fixing or steel erection, so both follow the general rules for building a structure. Making or bending steel off site and delivering it is outside the scheme, but a contract to supply and fix brings every payment under it into CIS. When you buy the steel yourself, its cost comes off before the deduction is worked out. A gang leader paid for the whole gang is the subcontractor, and is responsible for any deductions from the gang’s pay.

When CIS applies, a contractor deducts 20% if you’re registered for CIS, 30% if you’re not, and nothing if you have gross payment status. To work out a CIS deduction, the contractor starts with the gross invoice and takes away what the subcontractor paid for VAT, consumable stores, fuel (except for travelling), plant hire, manufacturing or prefabricating materials, and materials; the CIS rate is then deducted from the amount left.

Before you join Making Tax Digital, over-deducted CIS is claimed back through your Self Assessment tax return. Once you are in Making Tax Digital, HMRC adds your CIS deductions to your tax return, and any refund is requested separately through HMRC online services. Either way, the sooner after 5 April the return is filed, the sooner HMRC can repay you.

Estimate your CIS refund

Free, and it runs in your browser: add your van or mileage, tools and phone, for 2025-26 and 2026-27.

Costs steel fixers usually claim

The test for every cost is whether it was for your business. If something is partly personal, only the business part counts.

Your van, tools and kit

Most steel fixers carry tying tools, cutters and protective kit, while heavier bending kit is owned, hired in or supplied by the contractor. Kit you own is business equipment, but under CIS only kit hired from someone else, and fuel used on the job, is treated like materials. If you cut and bend at your own yard, keep the steel invoices for each job so the materials can be shown apart from your labour. Going from home to a run of temporary sites is business travel, and on a job too far to travel home from each day, the room and reasonable meals can be claimed.

From 2024-25 the cash basis is the default for sole traders and partnerships without corporate partners, with no turnover limit; traditional (accruals) accounting is an opt-out. Under the cash basis, the cost of equipment bought to keep and use in the business, such as machinery, computers and vans, is claimed as a normal allowable expense rather than a capital allowance. Cars are different: they go through capital allowances.

Simplified expenses for cars and goods vehicles (vans) from 6 April 2026: 55p a mile for the first 10,000 business miles, then 25p; motorcycles 24p. Once used for a vehicle you must keep using it for that vehicle, and it cannot be used for a vehicle already claimed through capital allowances.