Administrators Rob Lewis and Ross Connock of PwC said they were hoping to find a buyer for the business and save over 120 jobs.
The harsh winter weather of 2010 was given as one of the most significant challenges faced by the company, which been established for more than 50 years.
FH Gilman & Co has 75 staff based at its Pembrokeshire operations producing aggregates, ready mixed concrete and asphalt, and a further 47 are employed in Stamford at its headquarters, plant hire and warehouse operations.
Joint administrator Ross Connock said: “FH Gilman & Co is a well known business within its local markets with a strong reputation for quality and service, which was making significant progress in terms of its performance.
“Our main priority now will be to continue to trade the business while we seek a sale of the business and assets. In looking to achieve a sale, it will be critical that we retain the ongoing support of both the employees and the suppliers to the business.”