The £64m turnover contractor specialised in projects up to £15m in the housing, education, healthcare, lesiure and commercial markets across the South East.
Administrators from Crowe UK LLP took control of the company earlier this month.
Westridge was working on 49 new homes for Adur District Council in Southwick, West Sussex where it had been on site since 2021.
The council said: “We are now considering a number of options to allow the final steps of the project to be completed so that local families can move into the much-needed properties.
“They include working with another building contractor who would be able to pick up the work quickly, organising a managing contractor who would manage the final pieces of delivery or adopting the last stages of development management ourselves.”
Westridge was also working for housing association Saxon Weald.
It said: “Westridge Construction were a significant local employer, so we are saddened to hear that they have entered administration.
“This action will cause delays for us in completing our new homes both at Livingstone Road in Horsham and The Cobblers in Slinfold. We are working with our expert advisers to understand the implications for both sites, so that we can complete construction and get these homes to those that need them.”