HMRC will expect you to register for the Construction Industry Scheme (CIS) if you are either Self Employed or a Limited Company.
Once registered for the Construction Industry Scheme, a contractor (who you work for) will deduct 20% tax from your sales invoices and pay it to HMRC directly on your behalf. These deductions count towards your tax and National Insurance liability at the end of the year (31st Jan). Please note that if you do not register for CIS, contractors will deduct 30% tax from your income!
Usually a subcontractor (that’s you) will receive a tax rebate at the end of each year as they will have their personal allowance and usually some expenses to offset.
Fortress Accounts can help with maximising your tax rebate and register you for CIS if necessary!