Essex-based Masterframe Windows Ltd, which makes about 400 frames a week, said it had recognised that timber was being demanded in certain situations. It also pointed to the growing trend of timber window sales.

Timber sashes will be added to Masterframe’s Bygone range and offered through the company’s network of preferred installers.

“Adding timber to Bygone will continue to allow sensitive and appropriate period property refurbishment but with a wider choice of material,” said Masterframe managing director Alan Burgess. “Having part of the responsibility for maintaining Britain’s built heritage means recognising that, in some situations, timber is demanded by legislation or the property owner.”

Mr Burgess said the latest timber window research had showed timber window sales were continuing to grow, with further growth forecast for next year.

“We’ll be announcing more details of how our Bygone Preferred Installers will be contributing to this growth in the near future.”

Masterframe claims to make more PVCu sash windows each week than Everest, Anglian, Bowater Zenith and BAC put together.

“Our opinion trend monitors for the past year have shown that the timber window market is growing,” said British Woodworking Federation chief executive Richard Lambert. “And we know from surveys elsewhere that the PVCu window industry is stagnating, so it’s not surprising that companies who have focused solely on PVCu are looking to diversify.”