For centuries, mastic asphalt has been a trusted material for durable, waterproof roofing solutions, particularly within heritage and historic building projects. Mastic asphalt has stood the test of time with some applications providing effective waterproofing for an astounding 100 years or so, but effective installation is critical to ensure longevity and performance.
The skilled work involves heating the asphalt to the correct temperature and then spreading it using traditional techniques to carefully coat a surface. A thermoplastic material that will change shape when heated, mastic asphalt cools to form a hard, durable and waterproof coating.
Today, the Mastic Asphalt Council (MAC), the UK’s only dedicated trade organisation for mastic asphalt, is building on the legacy of mastic asphalt with a new initiative designed to give contractors the recognition they deserve – the MAC Certified Contractor status.
The scheme is aimed at providing clear differentiation for contractors who are members of MAC, recognising their time served, technical expertise, and commitment to the highest standards of quality. In doing so, it underlines mastic asphalt’s continued relevance as a trusted solution for heritage roofing.
The heritage market is a key sector for the industry and mastic asphalt is frequently specified by the National Trust and English Heritage, as well as other public and private owners of prestigious buildings for refurbishment projects.
A Heritage of Excellence
Since its formation, the Mastic Asphalt Council has championed best practice, technical guidance, and professional development in the UK mastic asphalt sector.
Membership has long been a mark of reliability and quality, signalling to customers that a contractor operates to rigorous industry standards. The new Certified Contractor status builds on this foundation, formalising a recognition framework that highlights experience, competence, and adherence to national standards.
Mastic asphalt remains particularly suited to heritage projects. Its durability, waterproof properties, and versatility make it ideal for flat roofs, terraces, and other applications on historic structures.
By aligning certification with MAC membership, the Mastic Asphalt Council is giving clients a clear assurance that their heritage roofing projects are in the hands of qualified and trustworthy installers.
What Certification Entails
The MAC Certified Contractor initiative sets out a structured approach to ensure certified installers meet the highest standards.
Key areas include:
1. Financial and Organisational Stability
Installers need to demonstrate good financial standing and provide evidence of successfully completed mastic asphalt projects. This ensures the contractor is reliable, experienced, and capable of delivering on their commitments.
2. Technical Competence and Proven Experience
Certification requires documented experience in mastic asphalt projects, compliance with relevant British Standards (such as BS 8218 and BS 6229), and adherence to industry Codes of Practice. This guarantees installers apply mastic asphalt to nationally recognised standards and best practice requirements. Contractors must also identify their asphalt distributor or supplier.
3. Compliance With Industry Regulations
Certified contractors must operate within the Working Rules and Conditions of the National Joint Council for the Mastic Asphalt Industry, confirm compliance with the Health and Safety at Work Act 2005 and associated regulations, including those related to scaffolding and safe site operations, and follow roofing sector Codes of Practice. The scheme thereby reinforces safe, responsible working practices.
4. Training, Skills and Workforce Competency
Contractors must provide evidence of employee qualifications (NVQs, City & Guilds, in-house training) and demonstrate that employees have adequate skills, competence, and continued professional development, providing a clear benchmark of workforce capability.
5. Membership of Recognised Industry Schemes
Installers are encouraged to show membership or accreditation with trade bodies such as the NFRC (National Federation of Roofing Contractors), CHAS (Contractors Health & Safety Assessment Scheme) and Constructionline, confirming commitment to professionalism, safety, and quality management.
Supporting Heritage and Craftsmanship
By introducing the Certified Contractor initiative, MAC not only recognises the skills and dedication of its members but also strengthens confidence in mastic asphalt as a heritage roofing solution. For architects, specifiers, and building owners, it provides a means of identifying installers who combine experience, technical knowledge, and a proven track record in high quality work.
Standing the Test of Time
There are many examples of heritage projects completed by MAC members where mastic asphalt has truly stood the test of time. Buckingham Palace is a prime example of its longevity. The rooftop of the Royal residence has been protected by mastic asphalt for over 80 years, successfully keeping the building dry.
Mastic asphalt was also first laid on the Stone Gallery of St Paul’s Cathedral in 1906. It delivered an impressive 111 years of weatherproof protection before refurbishment was required.
During the renewal of the Stone Gallery, approximately 20 tonnes of the original material were carefully preserved on-site for future reuse. Just nine months later, it was re-melted, sieved, and reused by MAC contractor Sussex Asphalte for another waterproofing project at St Paul’s Cathedral – this time on the North Courtyard.
In another notable heritage project, mastic asphalt was first applied to the roof of the National Museum Cardiff in 1910. It provided an outstanding 109 years of weatherproof protection before a full roof refurbishment was carried out, once again using mastic asphalt, applied by long-standing MAC member Cardiff Asphalt.
The MAC Certified Contractor status is more than a badge – it is a testament to the enduring quality, heritage, and expertise that mastic asphalt brings to the UK roofing landscape.
If you are interested in finding out more about the MAC Certified Contractor scheme, please contact Bryn Apperley at email: info@masticasphaltcouncil.co.uk.
This article featured within the 2026 Traditional Roofing supplement of Roofing Today – click here to view the article.