Timber external doors

Date Published

23 August 2022

Document Type




An external door has a demanding role to perform and is expected to maintain its level of performance over many decades. It is mechanically stressed throughout its life due to opening and closing. Its inner face is subjected to the heated dry interior of the building, while the outer face is often exposed directly to the elements, unless protected by a porch or protective canopy. It is often installed into a building which has not yet dried out, yet it is expected to remain flat and maintain the designed door-to-frame gaps both during and after the drying out period.

The architect, door designer, manufacturer, supplier, Build > Installer;, user and maintenance contractor form the chain of responsibility that leads to long-term satisfactory performance of timber external doorsets.

This Wood Information Sheet (WIS) discusses aspects of design and site practice which affect the performance of external doors.

Key Information

Specify external ‘doors’ as doorsets, complete with frames, factory painted.

Understanding the behaviour of timber in response to changes in its moisture content is vital for those involved in the design, selection and installation of timber doors.

In severe exposure conditions, protect the dorset using a canopy or porch to ensure satisfactory performance of the door and its finishing treatment.

Case studies

Pocket House is an award-winning family house, distinguished by its character, the quality of its detailing – much of it in timber
– and by the skill with which the architect has made use of a dauntingly restricted site.

On a Thames-side site which regularly floods, March House by Knox Bhavan architects has been designed for longevity by embracing the agency of the river.