The Project

Located on The Portman Estate, 4 Duke Street is a Grade II listed office building with residential accommodation on the third floor.

The building also has a famous English Heritage Blue Plaque which honours notable men and women who have lived and worked in buildings across London. In the case of 4 Duke Street, the plaque commemorates politician Simón Bolívar stating “SIMÓN BOLÍVAR 1783-1830 Liberator of Latin America lodged here in 1810”.

Following vacant possession by the previous tenant, the Portman Estate appointed PBC to act as lead consultant in undertaking a comprehensive internal and external refurbishment. Given the buildings status, this involved extensive liaison with the local planning authority to ensure all works were sympathetic to the age and character of the building.

The works involved full external repairs and redecoration works, layout alterations, extensive structural repairs, window replacement works, installation of new kitchens and tea points, replacement of all WC and bathroom facilities, installation of shower and locker facilities and replacement of floor coverings. With thermal performance in mind, insulation was upgraded to external walls as well as to floor voids and roof spaces. The entire mechanical and electrical systems were replaced with a new air source heat pump providing heating and cooling to the building.

The works undertaken meant that the building achieved an EPC rating of B, a vast improvement on the previous rating of E.

PBC Scope

PBC were tasked with forming the project team, gaining listed building consent for the works and preparing tender and design documentation along with the other project consultants. We sought competitive tenders for the works and reported to the client. Once on site, we acted as project manager and contract administrator to completion.

The main challenge of this project was ensuring that we provided high quality facilities and thermally efficient building whilst undertaking works that were sympathetic to the buildings age and listed status.

This involved upgrading single glazed sash windows to double glazing whilst retaining the existing window frames and installing an air source heat pump on the roof but building a false slate roof pitch to obscure it from view at the request of the planning authority.

We also installed aerogel external wall insulation to ensure that the reduction of floor area was kept to a minimum. The insulation of floors and roof spaces were upgraded using sheep’s wool to ensure breathability of the building.

The building is now occupied by a well-known law firm who have given excellent feedback on the space.

Client: The Portman Estate

Lead Consultant / Project Managers / Contract Administrator: Project & Building Consultancy (PBC)

Main Contractor: GD Construction (St.Albans) Ltd

Interior Designers: Garnett Architecture

Mechanical and Electrical Consultant: Taylor Project Services LLP

Structural Engineers: Furness Partnership

CDM Principle Designer: BAILY GARNER (HEALTH & SAFETY) LIMITED

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