Getting Started

How to Set Up as a Self Employed Builder UK — Complete Guide 2026

Updated July 2026 · 11 min read · BuilderLog Team

Going self employed as a builder is one of the best moves you can make. But the paperwork side catches most people out. This guide covers everything in the right order.

Step 1: Register with HMRC

Register as self employed at gov.uk. You’ll need your National Insurance number. You must register by 5 October in the tax year after you start. Do it on day one. You’ll receive a UTR number within 10 days.

Step 2: Get your CSCS card

Most sites require a CSCS card. You’ll need the relevant NVQ and the CITB Health, Safety and Environment test. The card costs vary by type. Fully claimable as a business expense.

Step 3: Register for CIS

If you’ll work as a subcontractor for other contractors, register as a CIS subcontractor with HMRC. This drops your deduction rate from 30% to 20%. Do this alongside your self assessment registration.

Step 4: Get insured

Public liability insurance (£200–£600/year) is essential. Employers’ liability is required if you hire anyone. Tool insurance covers theft from your van (£3,000–£10,000 worth of kit). All fully claimable.

Step 5: Open a business bank account

Keep business and personal money separate. Starling, Tide and Mettle offer free sole trader accounts. Apply online in 10 minutes.

Step 6: Sort your van

Choose between simplified mileage (55p/mile, simpler) or actual costs (more admin, sometimes bigger deduction). See our van claiming guide for a detailed comparison. Once you choose, you’re committed for the life of that vehicle.

Step 7: Set your prices

Most self employed builders charge £180–£350 per day depending on location and specialism. Don’t base your rate on your old employed wage — as an employee, your employer was paying NI, pension, holiday pay and van costs on top. Calculate your minimum rate (see our day rates guide).

Step 8: Keep records from day one

From April 2026, builders earning over £50,000 need Making Tax Digital compliance. Even below the threshold, digital records from day one save you pain at tax time. BuilderLog lets you log a job in 10 seconds, track costs per job, and generate your tax figures at year end.

What you can claim from day one

• CSCS card and test fees
• Public liability insurance
• Van mileage (55p/mile)
• Tools and equipment
• Skip hire and waste disposal
• Scaffolding hire
• Phone bill (business proportion)
• Workwear and PPE
• Training courses

Step 9: Tell people you exist

Word of mouth is the best source of work, but it takes time. In the meantime:

• List yourself on Checkatrade, MyBuilder, or Bark
• Create a Google Business Profile (free, essential for local search)
• Post in local Facebook groups when people ask for builder recommendations
• Leave a business card with every customer
• Get a simple website — even a one-page site with your name, phone number, and what you do

Common mistakes new builders make

Undercharging: Your day rate needs to cover your costs, tax, NI, holidays, sick days, and quiet periods — not just your hourly wage. Calculate your minimum rate properly.

Not registering for CIS: If you do any subcontract work and aren’t CIS-registered, contractors deduct 30% instead of 20%. That’s 50% more tax taken at source.

No public liability insurance: One accident on a customer’s property without insurance could bankrupt you. It’s £200–£600/year and fully claimable.

Mixing personal and business money: Makes your tax return ten times harder. Get a separate business account from day one.

Not keeping records: Every missed receipt is money you can’t claim. Start logging from your very first job.

Your first year checklist

• ☐ Register as self employed with HMRC
• ☐ Get CSCS card
• ☐ Register for CIS (if doing subcontract work)
• ☐ Get public liability insurance
• ☐ Open business bank account
• ☐ Set your day rate (calculate, don’t guess)
• ☐ Start logging jobs, costs and mileage from day one
• ☐ File self assessment by 31 January