Have you ever undertaken a task, or asked yourself a question, absolutely certain of what the outcome would be? Only to find that your certainty was misplaced?
Engineer Charlotte Garven was working on a residential project for an engaged and informed client – one who was trying to extract the lowest environmental impact from the project with the most sustainable materials. It was an ambition Charlotte shared.
In order to design and specify the most appropriate timber flooring for the home, she undertook a comparative study of a number of suitable options. Before she commenced the study, she was sure that natural sawn timber would provide the lowest embodied carbon figure.
‘Natural timber is considered by many to be the most sustainable form of mass timber construction, and my instinct was that it would prove the case on this design,’ Charlotte recalls. ‘But engineered timber has been designed to achieve greater bending strengths so, in the right situation, could it provide a more efficient system?’
Working closely with the architects, Charlotte’s brief was to keep floor depths as shallow as possible and to try to achieve an open spacing of the timber sections.
‘In a traditional joisted system we sometimes need to consider additional plasterboard linings to protect the plywood structure from fire,’ she explained. ‘But we looked to Cross Laminated Timber (CLT) and CLT Rib Panels which can be designed for charring, to omit this secondary lining and use it to our benefit.’ Of the four options studied (pictured below), CLT Rib Panels delivered the lowest embodied carbon figure, less than half that of natural sawn timber. The results surprised the engineer and pleased the client and architect. ‘We all agreed that the Rib Panel systems also look pretty great too.’
As the poet, EE Cummings once wrote ‘always the beautiful answer, who asks a more beautiful question.’