2 Willow Road, Hampstead, London
Project Overview
2 Willow Road is a Grade II* listed modernist property in Hampstead, London, designed by architect Ernő Goldfinger and completed in 1939. Now cared for by the National Trust, the building is recognised as an important example of British modernist architecture, with its flat roof forming a key part of the original design.
Grade II* is one of the highest levels of listed building protection in England. It applies to particularly important buildings of more than special interest, sitting between Grade I buildings of exceptional interest and Grade II buildings of special interest. For projects of this nature, any refurbishment work must be carefully considered to protect the building’s architectural and historic significance.
After more than 80 years, the existing roof had reached the end of its serviceable life and required sensitive refurbishment. The project involved carefully removing the original roof build-up, including concrete screed, cork insulation and domed rooflights, before rebuilding the roof with improved falls, high-performance insulation and a renewed mastic asphalt waterproofing finish.
Working with Bespoke Asphalt Ltd, the specification combined IKO Permascreed and IKO Permaphalt to deliver a refurbished roof that respected the building’s architectural character while improving drainage and long-term waterproofing performance.
Challenges
The main challenge was balancing heritage sensitivity with the practical requirements of a full roof replacement. As a Grade II* listed building, 2 Willow Road could not be altered in a way that affected its clean roof profile, geometric lines or original architectural intent.
The existing roof also had historic drainage issues, with ponding affecting long-term performance. Correcting the falls had to be achieved without changing the building’s external appearance or increasing the roof build-up beyond the constraints of the original detailing.
Thermal improvement added a further layer of complexity. Bespoke Asphalt needed to upgrade the insulation while maintaining existing upstand heights and ensuring the finished roof remained visually sympathetic to the property.
Careful removal of the original materials was also essential. More than 13 tonnes of aged roof build-up were taken off the building, with a section of the original roof retained for the on-site museum collection in recognition of the property’s heritage value.
Solutions
IKO Permascreed was used to recreate drainage falls across the roof and provide a stable base for the waterproofing system. More than 9 tonnes of IKO Permascreed were installed, helping to resolve the historic ponding issue while preserving the building’s original roof profile.
IKO Permaphalt was then installed as the waterproofing layer, providing a seamless mastic asphalt finish suited to the heritage setting. Its use helped retain the traditional appearance of the original roof while delivering a renewed waterproofing system designed to support the long-term protection of the property.
Bespoke Asphalt Ltd carried out the installation with close attention to the specification and the architectural detailing of the building. The completed roof provides improved falls, upgraded thermal performance and a visually sympathetic finish for one of London’s most distinctive modernist homes.
Project name and location:
2 Willow Road, Hampstead, London
Main IKO system:
IKO Permaphalt Mastic Asphalt Waterproofing System
Roof area:
85m²
Project sector:
IKO Guarantee:
20-year single point guarantee
Products:
Contractor:
Bespoke Asphalt Ltd