284 Woodpeckers


Hertfordshire, UK


Main Contractor:
BTA Structural Design

Timber Self Build Specialists:
Flight Timber Structures

Project Type: 
Self Build



The existing property sat within a densely forested section in Northwood, Hertfordshire. The site is bordered on one side by a main road and the remaining sides by large two to three storey properties.

The existing house is positioned centrally on the plot with a minimum distance to any boundary of 7.5 metres. The dense boundary planting of mature trees and shrubs creates a very limited outward view from the site and creates a very clear sense of privacy between adjoining properties.

The existing property had four bedrooms over two storey and was constructed in the late 1960's and further extended in the 1970’s with the inclusion of a single storey swimming pool room to the front of the property.

The original Colt House was constructed with a lightweight un-insulated timber frame and externally clad in render, cedar shingle, horizontal timber boarding and topped with a timber pantile roof.

The existing plan for the rear section of the house contained the living space, a playroom, bathroom, study, bedroom and utility area in a very convoluted arrangement and required access through interconnected rooms. This plan organisation fails to provide useful living areas and was a very irrational use of the floor space that failed to engage with the surrounding gardens.

The new owners approached us after seeing an earlier Colt House* refurbishment we completed in Suffolk. Woodpeckers had clearly been enjoyed, with some lively interior finishes and an original Poggenpohl kitchen still in functioning order to the front of the house.

The main goal for the new owners was to demolish the single storey rear extension and rebuild a new two-storey extension on the existing footprint. The proposed extension would provide a new heart to the family home, which was absent from the existing arrangement. The proposals would also bring the house up to current building standards in relation to thermal efficiency upgrades and further reductions in energy consumption through the integration of a new heating system.

At ground floor level, the new extension has at its centre a new family kitchen and adjacent dining space where all day-to-day proceedings occur. Adjacent to this area is the new family living areas with direct access to the retained mature garden. A separate ground floor guest bedroom and bathroom allows the top floor to remain as a private family area.

The front two-storey section of the existing house is to be sympathetically renovated and upgraded to a modern standard. The existing top floor of the front of the house has been renovated and connects through to the new extension to create a more free flowing circular route through the property. The top floor of the new extension contains a new main bedroom, bathroom and dressing area with framed views out to the surrounding gardens and maintaining the orientation away from the neighbours. A large double height void and breakout area allows for visual connection back down to the heart of the building below.

The proposals did not seek to alter any aspect of the existing street elevation except for minor refurbishment requirements and all existing trees and shrubs to the street side of the house were retained.

The external material finish of the extension is to be a dark grey render to the ground floor section and cedar shingle to the first floor walls and roof. The render band is to follow the current datums of the render band to the front section of the house and the cedar shingles are to match the existing gables of the front section of the house. The cedar roof finish has been incorporated to reduce the overall building weight and chosen for its long-term naturally weathering to a light grey so as to be harmonious with the pantile roof section to the front of the house. The glazing system for the new extension is a thermally efficient dark grey aluminium system.

A system of vertical timber louvres / fins create shading to the first floor void area while allowing views out to the gardens. The vertical fins and frame also accentuate the horizontality of the proposed extension. All materials have been chosen to improve and rework the original building vernacular.