‍‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‍SiteKiln gives you plain-English information, not legal advice. If you need advice specific to your situation, talk to a qualified accountant or tax adviser.

The short version

If you're self-employed in construction, you can claim expenses that are wholly and exclusively for your trade -- things like tools, genuine business mileage, site travel, PPE and some work clothing. You can either claim actual vehicle costs split between work and personal, or use HMRC's simplified mileage rates (45p per mile then 25p) to keep things simple.

Why it matters

Most subs massively under-claim -- they just guess a fuel number and forget half their kit and phone costs, so they pay tax on money they never really kept. Others go the other way and chuck in jeans, normal trainers and every drive they ever do, which is exactly the sort of thing HMRC challenge if they open an enquiry. Getting this list right means lower tax, less grief, and a straight answer if anyone ever asks "how did you work that out?".

This section is for self-employed construction workers -- sole traders and CIS subs -- not employees on PAYE or umbrellas. The rules are HMRC's general self-employed expenses guidance, plus some construction-specific bits, plus the simplified mileage rules if you want to keep van claims basic. The test is always the same: would you have spent this money if you weren't running the trade?

5.6.1 Travel, vans and simplified mileage

You have two main ways to claim vehicle costs.

Option 1 -- Actual costs

You:

Add up all running costs for the year -- fuel, insurance, tax, MOT, repairs, tyres, breakdown cover, parking and tolls.
Work out a reasonable business percentage (for example 70% work, 30% personal) based on mileage or trips.
Claim that percentage of the total as an expense.

You cannot claim:

Normal commuting to a permanent place of work -- only genuine business travel between jobs, to temporary sites, to merchants, quotes, etc.

Option 2 -- Simplified mileage (HMRC flat rate)

Instead of actual costs, you can use HMRC's mileage rates (simplified expenses):

Cars and vans: 45p per mile for the first 10,000 business miles in the tax year, then 25p per mile after that.
Motorcycles: 24p per mile.
Bicycles: 20p per mile.
Extra 5p per mile for each business passenger in a car or van.

You just track business miles and multiply by the right rate -- you don't then also claim fuel, insurance, or depreciation for that vehicle. Once you pick mileage for a particular vehicle, you generally stick with it while you use that vehicle in the business.

5.6.2 Tools, kit and consumables

HMRC are fairly relaxed about normal business kit if it's clearly for work.

Common allowable items:

Hand tools and power tools -- drills, impact drivers, saws, nail guns, batteries, chargers.
Consumables -- blades, drill bits, discs, sandpaper, screws, fixings, gas and nail packs.
Small kit -- leads, chargers, site radios, head torches, tool bags and boxes.
Testing equipment -- multimeters, testers, laser levels.

Most day-to-day tools are treated as normal expenses (you claim them in full in the year you buy them). Big stuff that will last years -- like a van or expensive machinery -- is usually claimed via capital allowances, but the main point here is: keep invoices, and don't be shy about putting genuine work kit through.

5.6.3 Clothing, boots and PPE

HMRC are strict on clothing -- they only like uniforms and protective gear, not normal clothes.

Generally allowable:

Protective clothing and PPE needed for the job: safety boots, steel toe caps, hard hats, safety goggles, hi-vis, overalls, specialist protective jackets and trousers.
Branded workwear that's clearly part of your trade -- for example, tops with your logo, where they're not really everyday fashion.
Cleaning and repair costs for that specific work gear.

Not allowable:

Everyday clothes like jeans, hoodies, non-safety trainers, even if you only wear them for work.
Smart casual clothing that you could wear off site.

For employees there's a separate PPE duty on employers, but for a self-employed sub buying their own boots and helmet, those are normally OK as business expenses.

5.6.4 What travel you can and can't claim

Allowed travel (as self-employed):

Trips to temporary sites and different jobs.
Travel between sites during the day.
Trips to merchants, suppliers, tip/rubbish runs and quotes.
Overnight stays and meals when you have to stay away for work, not just because you fancy it.

Not allowed:

Regular commuting to the same permanent workplace, if that's effectively your base.
Personal trips that happen to be near a job.

When in doubt, ask yourself: "If I wasn't doing this job, would I still be making this journey?" If yes, it's not business.

5.6.5 Quick "yes/no" checklist for builders

This is the mental filter to run through before you stick something in the books:

Tools and small kit for site work? Usually yes -- keep the receipt.
Van fuel and running costs? Yes, either as business share of real costs or via mileage.
Driving from home to different sites/clients? Usually yes -- that's business travel.
Driving to the same yard or office every day for years? Usually no -- that's commuting.
Safety boots, hi-vis, hard hat, overalls? Yes, these are protective clothing.
Jeans and hoodies? No, even if you only wear them on site.
Normal lunch at your usual site? Generally no.
Extra costs when you're working away overnight? Often yes -- hotel and reasonable meals.

If you're not sure, park it in a "maybe" pile and get an accountant to give it a thumbs up or down once a year.

Putting it together -- mileage and tools example

Say you're a self-employed sub using simplified mileage and buying your own kit.

Over the tax year you have:

2,000 business miles in your van (site to site, merchants, quotes).
£800 of new tools and PPE (drill, batteries, blades, safety boots, hi-vis).

Using HMRC's mileage rates and expense rules:

Mileage claim: 2,000 miles x 45p = £900 allowable vehicle expense.
Tools and PPE: the full £800 as allowable business expenses.

Total extra deductions you put on your Self Assessment:

£900 + £800 = £1,700 taken off your taxable profit.

If you're in the 20% tax band, that £1,700 of claimed costs would typically knock about £340 off your income tax bill, plus some saving on Class 4 NIC. All for things you had to buy anyway, as long as you kept half-decent records.

What to do next

Pick either actual vehicle costs or simplified mileage for your van and stick with that method consistently.
Start logging business miles properly -- date, from/to, miles, job -- even a simple phone note will do.
Keep receipts for tools, PPE and fuel in one place, not scattered across pockets and dashboards.
Review your expense categories once a year with your accountant to make sure you are not under-claiming or over-claiming.

Sources and legislation

Income Tax (Trading and Other Income) Act 2005 -- allowable deductions for self-employed trading expenses. legislation.gov.uk/ukpga/2005/5
Income Tax (Earnings and Pensions) Act 2003 -- travel and protective clothing rules (mainly for employees, principles useful for self-employed). legislation.gov.uk/ukpga/2003/1
Social Security Contributions and Benefits Act 1992 -- Class 4 NIC on self-employed profits. legislation.gov.uk/ukpga/1992/4

5.3 Filing Self Assessment -- construction-specific deductions
5.11 Annual investment allowance
5.15 Record keeping
5.1 Registering as self-employed for construction
14.8 Materials -- who supplies, who pays
S9 Setting up as a sole trader -- step by step

Common questions