A TIMBER specialist is expanding after completing contracts for two landmark buildings.

Robert Duncan Timber, in Gateshead, is enlarging its five-acre headquarters in Felling to meet an expected ten per cent increase in production.

The group, which also has centres in Middlesbrough and Leeds, employs 83 staff.

The increase in work follows two high-profile orders for its treated and machined timber.

It supplied wood for the tree house in the Duchess of Northumberland's showpiece garden at Alnwick Castle in Northumberland, and for the cedar-clad £5m Quadrus office block at Boldon Business Park in South Tyneside.

The deals were worth £200,000 to the family firm, which was founded in 1946.

Robert Duncan, chairman, said: "The buildings are like chalk and cheese, so completely different from each other, yet each prestigious in their own way - making us particularly proud to have worked on both."

The treehouse, outside the walls of Alnwick Castle's main garden, covers 6,000sq ft, making it one of the largest treehouses in the world.

Sales director Angus Beston said: "We sourced and treated douglas fir poles from Scotland and other speciality hard and soft woods, such as balau and oak, from around the world.

"As a job, it was a rare, Disney-like opportunity, and one we would happily tackle again, though treehouses like this are not everyday constructions."

For Quadrus, a wood cladding was chosen to harmonise with the business park, which has a fishing lake and wetlands with nesting swans.