Union bosses are now calling on other contractors to follow suit and boost their terms beyond the statutory rate which can be as little as £16 per day.
Unite regional officer for the construction sector Malcolm Bonnett said: “Unite has been campaigning hard to end the discrimination on sick pay for construction workers so we’re delighted by this victory.
“Statutory sick pay in the UK is the lowest in Europe so it was vital we persuaded the employer, a wealthy business, that they had a duty to pay when workers are ill.
“From here, we build further. Unite is determined that other construction employers act to end sick pay discrimination, too.”
A Kier spokesperson said: “At Kier, we recognise that our people are our greatest asset and our teams have been working hard to provide industry-leading policies and measures to support our people.
“In the last 12 months, we have launched improved family-friendly policies, our new and enhanced standard for sick pay for all and we have become signatories of the Real Living Wage.
“All of these actions reflect the plans we put in place as a result of our strategic review. They form part of our Performance Excellence culture and underline our focus and commitment on doing the right thing.”