Contact information
Business Description

Founded in 1992, A D Practice Ltd is a small, well-established and multidisciplinary architectural practice located in The Mill, Wheathampstead, St Albans, Hertfordshire.

We aim to work with clients and value our ability to listen and learn from them in order to create better spaces that both work for people and improve their quality of life. We work in BIM (Building Information Modelling) meaning that we can offer 3D visualisations of all our schemes, no matter how small, which can aid the understanding of the design for both clients and planners.​

Sustainability is at the heart of this philosophy and every design we produce. As members of several sustainable building associations and Certified Passivhaus designers, we design buildings that are healthy for both the planet and occupiers, using natural construction materials and renewable energy sources where possible, minimising the energy used by our buildings and setting them sensitively in nature to maximise natural daylighting and enhance local biodiversity.

We offer a full range of design services including specialised planning services and design development; initial feasibility studies; planning permission consents and appeals; building regulations; sustainable design; energy efficiency advice; site involvement and project management. We are also members of the Passivhaus Trust and Green Register.

We have a varied client base from both the public and private sectors, commissioning bespoke and developer-led schemes.Completed work includes individual residential new-builds and developments; extensions and refurbishments; commercial schemes; conservation and listed building work; primary, secondary and tertiary level education projects; restaurant and retail fit-outs; ecclesiastical; healthcare and community projects.

A D Practice Ltd

United Kingdom
Harpenden EnerPHit Plus

Deep retrofit of a 1960s detached house in Harpenden and the addition of a small rear extension.

This project meets the EnerPHit Plus (Passivhaus) retrofit criteria as well as going ‘gas free’ by using an air source heat pump and harnessing renewable energy with an entire roof pitch dedicated to solar pv.

The existing brickwork walls have been externally insulated using wood fibreboard finished with a painted render and timber cladding. The curtain walls were removed and replaced with new highly insulated timber I beam walls with cellulose insulation and clad in western red cedar or grey tiles to match the rear roof slope. The rear single storey extension was also constructed in this way and finished with either render or timber cladding. The existing ground floor was removed and replaced with a new highly insulated slab with underfloor heating.

St Albans Passive Houses

The dwellings are to be constructed from prefabricated timber frame panels which are insulated using cellulose insulation. The southern and western roof slopes will use solar panels as the roof finish. This will further reduce the energy demands of the houses and supplement the hot water requirements, the rest of which will be provided by air source heat pumps. The walls are to be finished in a mixture of lime render and locally sourced western red cedar cladding which provides a sustainable and breathable construction solution.

All three properties make the most of the natural light available on the site through the clerestory windows and having tall strip windows and voids through the floor plates, ensuring that as much light as possible reaches into the middle of the ground floor, providing an excellent internal environment for the inhabitants, which, when coupled with the MVHR ventilation system will create a very healthy living environment, free from pollutants and allergens.

Sustainable Listed Barn Conversion

We have been commissioned to provide a detailed design scheme for the conversion of Grade II Listed barns and farm buildings into five high quality environmentally sustainable dwellings.

David Parry
Heather McNeill
Director and Certified Passivhaus Designer
Nimmiya Mariam
Part 2 Architectural Designer