An expansion project for a special school in Enfield, North London, has made good use of thermally broken windows supplied by Crittall Fendor.

Durants School is expanding to meet an increased demand for places for children with autism. As the existing school site had reached capacity it was decided to transform a classroom block at nearby Minchenden minchenden School, in Southgate.

Architects BHP specified new double-glazed thermally broken steel windows to replace the original non-thermally broken single glazed fenestration. The windows in the two-storey building – which dates from the early 1950s – mimic perfectly the appearance of the ones they are replacing but incorporate modern thermal requirements.

20190704 113934 A total of 804 top-hung steel windows and 14 fully glazed steel doors have been supplied by Crittall-Fendor for the project. Overall U value for the completed project is 1.8 W/m2K based on a glass centre pane value of 1.0 W/m2K. The double glazing incorporates toughened low E glass and an 18mm argon filled cavity.

The new windows have been weather tested in laboratory conditions to BS EN 14351 – 1 and site tested successfully by independently accredited test house Wintech. The overall window acoustic value is Rw33dB.

All these values met the requirements of the specifier and client although Crittall Fendor windows are also available with a higher rating – down to a U value of 0.4 W/m2K at centre pane – if requested. Similarly, improved acoustic ratings can be achieved, if required, by utilising alternative glass specifications.

The newly-completed school buildings will be welcoming their first students this September. This will allow work to begin improving the original Durants School site. When this work is finished a year later the original site will become known as Durants Lower School and the former Minchenden buildings Durants Upper School. The development on both sites allows the school to create an additional 100 places for young people with autism.