General builders and multi-trade sole traders often have the most complex CIS position of any construction worker. Multiple contractors, varied work types, significant materials supply and the need to manage both CIS subcontractor income and any contractor-side obligations make getting the accounts right genuinely important.
Many builders both receive CIS deductions as a subcontractor and make deductions as a main contractor when paying their own subbies. Managing the HMRC offset position, filing CIS300 monthly returns correctly and keeping the two positions separate requires careful attention. A mistake in either direction creates problems.
Builders often work for several main contractors simultaneously or sequentially. Each uses their own deduction slips and may handle the labour/materials split differently. We consolidate all your CIS statements across the year to build the complete picture.
If you operate as a main contractor (i.e. you pay subcontractors), you must now file a CIS300 nil return for any month in which you make no subcontractor payments. This obligation was reinstated from 6 April 2026. Failure to file on time carries penalties starting at £100.
We consolidate all your CIS statements, account for all allowable expenses, and submit your Self Assessment return to claim the full refund you are owed.
If you pay subcontractors, we file your CIS300 monthly returns on time, verify subcontractor status before each payment, and manage nil returns in inactive months.
Builders with net CIS turnover over £30,000 can apply for GPS. We handle the application, the three-test compliance assessment, and the ongoing record-keeping.
Book a free call. We will talk through your CIS position, your deduction history and whether there is anything worth changing. No hard sell, no obligation.
Other trades we work with