Pre-finished timber windows now make up about 43% of the wooden window market, according to a report from Palmer Market Research Ltd.

The “Industrial Woodcare Market” study, the first research Palmer has devoted exclusively to the £10m sector, shows that two-thirds of joinery manufacturers contacted expect full factory finishing of all products to continue to grow.

The rising use of water-based finishes instead of solvents is also expected to boost pre-finishing, due to difficulties in reliably applying waterborne coatings on-site.

Robert Palmer, of Palmer Market Research, said: “Architects and builders are becoming more aware that factory finishing gives a more durable finish, and thus leads to reduced maintenance.”