Timber frame design for flood-prone sites

Timber frame design for flood-prone sites

Date Published

17 August 2022

Document Type

Category

Audience

Author

TRADA
Summary

It is apparent that the rapid expansion of development on river flood plains over recent years has placed more people at risk of flooding, while reducing the ability of the natural flood plain to absorb rising water levels.

Land available for housing is increasingly at risk of flooding due to several factors including storm water runoff from paved surfaces and the more extreme weather events the UK is experiencing.

The increased risk, combined with pressure for more housing, is causing local authorities to reassess the criteria by which land is deemed suitable for development.

The measures described in this Wood Information Sheet (WIS) summarise the many practical steps that can be taken – often for little extra cost – to make timber frame construction flood resistant and resilient, and likely to comply with the evolving building regulations.

The content has been revised to include minor amendments to the text and to provide some updated guidance on specifying timber for enhanced flood resilience.

Key Information

In the UK (where flooding is not an everyday occurrence or concern), the most sensible and cost effective approach would be to raise the building or the lowest floor level above the known flood levels for that particular area.

Alternatives for flood avoidance include sustainable urban drainage systems, such as porous paving, and strategies to provide draining routes and pools within a site to contain flood waters.

The timber frame itself is generally flood resilient. It is the ‘typical’ sheathings, linings and insulation that are likely to suffer from flooding.

Case studies

The new Refectory at Norwich Cathedral, the first stage of development to help sustain the future life of this important church, was completed in 2004 and received the Gold Medal at the 2004 Wood Awards.

In 2003 Meredith Bowles completed a timber frame home for his family and an office for his architect’s practice in the Fens village of Prickwillow near Ely in Cambridgeshire.