The company joined Fortis on September 1 after several months of negotiations and its inclusion in the group brings the latter’s membership to 40 and its combined turnover to more than £1bn.
"We would like to welcome Lawsons to the group, who have the same strategic approach to the market and want to work with us to offer suppliers the first credible alternative to the nationals," said Fortis chairman John Parker.
Lawsons managing director Tony Munkley said he was looking forward to becoming "an active contributor" to Fortis, adding: "The decision to become a member of a dynamic buying group was a logical one".
Lawsons was established in 1921 as a supplier of timber and fencing. The company now trades via its three brands of Lawsons (Whetstone) Ltd, Crowthorne Fencing and Sharvatt Woolwich Ltd.
The company, which has more than 300 employees, supplies timber and building materials from 17 branches throughout London and the south-east.
