The Construction Industry Scheme (CIS) is a specialised set of tax rules for the construction industry.  You sign up to CIS when you switch from working PAYE to being self-employed in the building trade.  The scheme is HMRC's attempt to crack down on ''cash-in-hand'' tax evasion scams in the industry.

Under CIS, your contractor takes 20% of your pay and send it to HMRC as an advancement toward the tax you'll owe.  Every year, RIFT Tax Refunds helps thousands of construction workers with their CIS problems, questions and refunds.  Here are some of the frequent questions we tackle.