Duchy of Cornwall review of window materials at Poundbury

In 2021, the Duchy of Cornwall undertook to review its policy of only allowing timber windows at Poundbury, as opposed to other materials such as uPVC, aluminium or aluminium composite windows.

This review followed an approach by a group of residents at Poundbury (the Window Group), seeking to widen the choice of materials permitted for replacement windows and doors at Poundbury. In particular, the group felt that the current rule prohibiting uPVC was unhelpful, outdated and needing to be revised.

In reviewing the policy the Duchy carefully considered the points and background information provided by the Window Group, and assessed both aesthetics and sustainability.

The Duchy’s decision is to maintain the requirement to use timber windows as set out in the Design and Community Code.

When Poundbury is completed in around five years’ time, it will consist of some 2,700 homes. From the outset of the development, creating a sustainable community in every sense of the word and reflecting the architectural heritage of Dorset and Great Britain, has been fundamental.

In line with this approach, the decision to use timber windows is embedded within the original vision of His Royal Highness The Duke of Cornwall and the Masterplan, as one of the 10 principles of the development – to use natural materials, which marry the principles of sustainable development with good quality design, using traditional styles of architecture in a local vernacular.

The Poundbury principles are upheld by the Deeds of Covenant and associated Estate Stipulations, as shown in the Code. These apply to and benefit every resident and owner, to maintain a coherent standard across all properties, irrespective of size or tenure, and to safeguard against the erosion of the sustainability objectives and architectural harmony which define Poundbury as a place.

At a time of climate emergency, using natural sustainable materials rather than manufactured and processed products is a base principle which should be upheld. The Duchy appreciates that specific uPVC products can now demonstrate stronger environmental credentials than their forebears, but it remains a material with significant embodied carbon. On this basis, the original specification of timber remains as justifiable today as it did 30 years ago, accepting that the manufacture and maintenance of timber windows naturally involves an element of carbon debt.

Sustainably sourced, good quality and professionally installed timber windows, which are then suitably maintained, therefore remain the appropriate material specification at Poundbury.