Mastic Asphalt Council (MAC) contractor member Sussex Asphalte has completed an impressive mastic asphalt project at Christ’s Hospital independent school in Horsham, West Sussex.
The roof refurbishment project at this heritage-rich site was so impressive that it was shortlisted for the ‘Best Heritage Project’ at the MAC Awards 2022. Established in 1552, Christ’s Hospital is one of the oldest boarding schools in England and is situated in 1,200 acres of Sussex countryside. The school has over 820 boarding pupils with an equal number of boys and girls, and takes day pupils.
Christ’s Hospital is the UK’s leading charitable school and the largest bursary charity, providing free or substantially reduced cost places to three quarters of its pupils each year. The school won the accolade of ‘Independent School of the Year’ at the Independent School of the Year Awards 2022 and is well known for its distinctive uniform which has barely changed since Tudor times. Pupils wear a long blue coat belted at the waist and white neck bands.
The school building is Grade II* listed. Its name derives from the fact that it is one of the famous Royal Hospitals of London, whose foundation marked the beginning of the social services in Tudor England. The school was the result of a foundation by Henry VIII and confirmed by Edward VI, assisted by Nicholas Ridley, Bishop of London and Sir Richard Dobbs, Lord Mayor of London.
The refurbishment was carried out by Sussex Asphalte as part of a wider school renovation and one of the key stipulations was to help Christ’s Hospital preserve its historic estate. Sussex Asphalte worked in conjunction with Kevin Bashford of MacConvilles of Brighton.
The project involved stripping the 250m² of existing defective coverings down to the flat concrete slab, and laying new mastic asphalt in two coats, finished with two coats of solar reflective paint. The stripping of the existing mastic asphalt coverings posed various challenges. Most notably, the stripping itself was made extremely difficult due to the multiple layers of varying materials used to coat and overlay the roof area over the years.
Upon removal, Sussex Asphalte’s operatives uncovered multiple layers of mastic asphalt, felt and liquid roof coverings. In addition to this, the removal of the existing waterproofing exposed electrical cabling feeding the lighting below. Additional care had to be taken when breaking out the existing build up to ensure no damage to the conduit or cables within. Operatives also had to be cautious when laying the new asphalt, ensuring the conduits were suitably protected to avoid them melting from the residual heat of the fresh mastic asphalt covering.
Though the life expectancy of mastic asphalt has been estimated at 50-60 years by the Building Research Establishment (BRE), there are many cases of asphalt roofs providing effective waterproof protection for up to 80-100 years. In terms of quality of workmanship, mastic asphalt is one of the few construction activities still regarded as a ‘craft trade’.
The skilled work involves ensuring that asphalt is at the correct temperature, and then spreading it using traditional techniques to coat the surface. A thermoplastic material that changes shape when heated, mastic asphalt cures to form a hard, durable, finished product to suit a wide range of applications.
To maintain the industry’s reputation and ensure high quality applications for every single project, only trained applicators are permitted to install mastic asphalt under the Mastic Asphalt Council’s strict rules. Being a MAC member enhances the reputation of a contractor and gives a badge of quality and assurance that they meet very highest of standards with regards to factors such as trading and credit history, insurance policies and quality of workmanship. Sussex Asphalte has trained several apprentices through the mastic asphalt apprenticeship at New City College Hackney which is the national centre for mastic asphalt education and training.
The mastic asphalt craft is taught by professional tutors at New City College Hackney and the traditional time-served apprenticeship is now incorporated into national vocational qualifications, leading to a Level 2 qualification. The craft training programme is said to be one of the most demanding in the construction industry, and includes practical and theoretical training to use mastic asphalt across a wide range of applications.
Apprentices employed by Sussex Asphalte were able to play a role in the project completed at Christ’s Hospital. The apprentices were able to assist the chargehand and skilled operatives to carry out the installation with skill, speed and accuracy.
This article featured within the February 2023 edition of RCi magazine – click here to view the article.