Roadworks in Billingshurst High Street are set to stay for an extra two weeks after excavators unexpectedly struck concrete.
The gas main works for a new housing development were due to be completed last Friday after five weeks.
But West Sussex County Council has had to extend the road closure until April 27 after contractors for Gas Transportation Company (GTC) had difficulties with the ground conditions.
A spokesperson for GTC said: “Groundworkers have come across unexpected layers of concrete within the ground in which they are excavating, this has caused delays in getting to the gas network below.
“We apologise for the disruption and any inconvenience this may cause.
“If you have any queries or concerns regarding the roadworks, please do not hesitate to contact our Customer Service Team on 01359 243292 or at email@example.com and we will be happy to assist you.”
Business have complained about the impact of the roadworks, which began without road signs to say that businesses were still trading in the closed part of the road.