General rule: a self-employed subcontractor can deduct allowable business costs when calculating taxable profit. Personal costs are not deductible, and mixed business/private costs normally need to be apportioned.
Common construction business expenses
Tools & equipment
Tools, consumables and qualifying equipment used for the trade may be deductible, with the accounting treatment depending on the item and accounting basis.
Protective clothing
Genuine protective equipment required for the work can qualify. Ordinary everyday clothing generally does not simply because you wear it at work.
Vehicle & travel
Allowable business travel and vehicle costs can qualify, but ordinary private travel and commuting rules need care.
Phone & software
Business use of phone, internet, bookkeeping software and other subscriptions may qualify; private use should be excluded.
Materials
Materials purchased for jobs are normally business costs. Under CIS, qualifying materials paid for directly by a subcontractor can also affect the amount on which the contractor calculates the CIS deduction.
Accountancy and professional fees
Business-related accountancy and professional fees can be allowable, although the cost of preparing the personal Self Assessment return itself has specific restrictions.
Working from home
If you genuinely use home space for business administration, a reasonable business proportion of certain costs or simplified expenses may be available.
Keep evidence
Keep invoices, receipts, mileage records and notes explaining unusual items. Digital bookkeeping makes this much easier than reconstructing a year of expenses at the deadline.
Frequently asked questions
Can I claim work clothes?
Protective clothing and specialist workwear can qualify, but ordinary clothing is normally private even if you only tend to wear it for work.
Can I claim my van?
Business vehicle costs may be allowable. The correct method depends on the vehicle, accounting basis and whether simplified mileage is used.
Can I claim my accountant?
Business-related accountancy fees can generally be deductible, but purely personal tax-return preparation is treated differently.