It’s the circular economy in action — a very low embodied carbon solution using today’s technologies

Whitby Wood is leading a Built by Nature-led consortium of UK and European partners in the development of an open-source interactive website that will enable city planners and asset owners to quickly understand the vertical extension potential of their buildings.

Case studies will demonstrate the application of optoppen to common building types in European cities, focusing on the UK, Netherlands and Spain.

Contact us to find out more

Optopppen project
Optoppen at Built by Nature : >

Whitby Wood, Creative City Solutions, Holland Houtland, Institute for Advanced Architecture of Catalonia, Mule Studio, New Urban Networks EU and Rising Tide


How do we get to zero-carbon construction? Optoppen, or topping up, is one way

Lightweight roof extensions — using timber and other bio-materials — increases the floor area in existing buildings, contributing to urban decarbonisation targets, densification strategies and more-efficient use of existing infrastructure. It’s the circular economy in action — a very low embodied carbon solution using today’s technologies.

Reusing existing building frames, and adapting and extending existing building stock, is a logical response to the challenges the construction industry faces in meeting climate targets. Lightweight vertical extensions increase the amount of additional floor area achievable using the capacity of existing foundations and structure.


Our team is experienced in all aspects of delivering this kind of project, many of which combine refurbishment, adaptation, retrofit, infill design, and facade extension, as well as optoppen and advanced timber engineering.

Adding floors creates value and enables energy retrofits of existing building stock. Optoppen using bio-materials has potential city-scale impact, enabling the creation of carbon sinks on top of our cities.

CONTACT : Kelly Harrison

See also Plotting our route to zero >