If you work in construction, you probably spend a fair chunk of your week behind the wheel. Groundworkers, bricklayers, scaffolders, electricians, joiners — the job demands constant travel between sites. The good news is that most of those miles qualify for mileage tax relief under HMRC’s temporary workplace rules, potentially saving you hundreds or even thousands of pounds each year.
This guide explains exactly which journeys you can claim, how the 24-month rule works on construction sites, and what to do whether you are self-employed under CIS, on PAYE, or working through an agency.
Why Construction Workers Have Strong Mileage Claims
Construction sites are temporary by nature. A house extension lasts a few weeks, a new-build estate might run six months, and even a large commercial project typically wraps within 18 months. Because each site has a defined start and end date, most construction workplaces meet HMRC’s definition of a temporary workplace — and travel to a temporary workplace is claimable business mileage.
This applies to every type of journey:
- Home to site — claimable if the site is a temporary workplace
- Site to site — always claimable when you travel between two work locations during the day
- Home to yard or depot, then to site — the full round trip qualifies if the site is temporary
Unlike an office worker with a single permanent base, construction workers regularly attend different locations. That pattern of changing sites is precisely what makes your mileage claims so valuable.
The 24-Month Rule and the 40% Test
HMRC defines a temporary workplace as one where you attend for a task of limited duration, provided the engagement does not last (or is not expected to last) more than 24 months. There is also a secondary condition: you must spend more than 40% of your working time at that location for the 24-month clock to matter.
In practice, this means:
- Short projects (under 24 months) — the site is temporary throughout, and all travel is claimable.
- Long projects (over 24 months) — once you know the engagement will exceed 24 months, the site becomes a permanent workplace from that point. Travel from home to that site stops being claimable.
- Contract extensions — if you initially expected a 12-month job but it gets extended to 30 months, you must stop claiming from the moment you become aware it will exceed 24 months.
The proximity rule also matters. If you move from one construction site to a nearby site and the journey from home is substantially the same distance, cost, and route, HMRC may treat both sites as a single location. This could push you over the 24-month threshold even though the site name has changed.
For a deeper look at how HMRC applies these rules, read our full guide on temporary workplace rules for mileage.
How CIS Subcontractors Claim Mileage
If you work under the Construction Industry Scheme as a self-employed subcontractor, you file a Self Assessment tax return each year. Mileage to temporary construction sites is a legitimate business expense you deduct from your taxable income.
You have two options:
Option 1 — Simplified mileage rate (most common)
- 45p per mile for the first 10,000 business miles per tax year
- 25p per mile for every mile above 10,000
Option 2 — Actual vehicle costs
- Claim the business proportion of fuel, insurance, servicing, repairs, road tax, and depreciation
- Requires keeping every receipt and calculating the business-use percentage
Most CIS subcontractors choose the simplified rate because it demands less paperwork — you only need a mileage log rather than a box of receipts. With either method, you deduct the total from your self-employment income on your tax return and reclaim any overpaid CIS deductions at the same time.
Example — Mark, a CIS bricklayer in Birmingham: Mark drives to three different housing sites each week. His annual business mileage totals 18,000 miles. Using the simplified rate:
- 10,000 miles x 45p = £4,500
- 8,000 miles x 25p = £2,000
- Total deduction: £6,500
At the basic rate of income tax (20%), that saves Mark £1,300 in tax plus additional National Insurance savings. With Tripbook logging every journey automatically via GPS, Mark does not need to write anything down — he simply reviews and confirms each trip at the end of the week.
For more on choosing between the two methods, see our comparison of actual costs vs mileage rate for the self-employed.
Employed Construction Workers — Claiming via P87
If you are employed on PAYE and your employer does not fully reimburse your site travel at 45p per mile, you can claim the shortfall as Mileage Allowance Relief (MAR).
Here is how it works:
- Employer pays nothing — you claim the full 45p/25p rate
- Employer pays less than 45p per mile — you claim the difference (e.g., if they pay 20p, you claim 25p per mile)
- Employer pays 45p or more — nothing further to claim
If your total expenses claim is £2,500 or under, use HMRC form P87 (available online). Above £2,500, you must file a Self Assessment tax return.
Many PAYE construction workers miss out on MAR entirely because they do not realise they can claim. If you have been driving to temporary sites without reimbursement for the past four years, you can backdate your claim — HMRC allows claims up to four tax years in arrears.
SDC Rules for Agency Construction Workers
If you work through a recruitment agency, the Supervision, Direction, and Control (SDC) rules introduced in April 2016 affect what you can claim.
The SDC test asks whether any person in the contractual chain has the right to supervise, direct, or control the manner in which you carry out your work. In construction, most agency workers are considered to be under some degree of SDC because site foremen or project managers direct how tasks are completed.
When SDC applies:
- You cannot claim travel and subsistence expenses as tax-deductible through an umbrella company
- Your assignment location is treated as a permanent workplace for tax purposes
- The main exception is statutory mileage allowance for travel between temporary workplaces during the working day (site-to-site travel)
If you can demonstrate that you are genuinely not subject to SDC — for example, you are a specialist subcontractor who decides your own methods — then the temporary workplace rules apply normally and you can claim home-to-site travel. However, HMRC sets the default assumption that SDC does apply, so the burden of proof falls on you.
Keeping HMRC-Compliant Records
HMRC expects a contemporaneous mileage log — a record made at or near the time of each journey, not reconstructed months later. For each trip, you need:
- Date of the journey
- Start and end addresses (site name is helpful)
- Miles driven
- Business purpose
With construction workers often visiting two or three sites per day, manual logging is unrealistic. Tripbook uses GPS to capture every journey in the background. At the end of each day you simply swipe to confirm which trips were business mileage, and Tripbook generates an HMRC-ready report you can hand to your accountant or attach to your Self Assessment.
For a full breakdown of what HMRC expects, read our guide on business mileage record-keeping.
Construction workers are among the highest-mileage professionals in the UK, yet many leave money on the table by not tracking their journeys properly. Whether you are a CIS subcontractor filing Self Assessment or a PAYE employee submitting a P87, accurate records are the difference between a successful claim and a missed opportunity.
Download Tripbook from the App Store and start logging your site visits today — setup takes under a minute, and every mile you track is a mile you can claim.
