Roof Refurb for Historic Hurst Castle

Hurst Castle - IKO Permaphalt

Marcus Lee, Divisional Sales Director of global waterproofing and roofing leader IKO PLC, on its award-nominated project for English Heritage

Hurst Castle in Milford-on-Sea is a stunning 16th Century fortress built by Henry VIII as one of a chain of coastal strongholds. In 2017, an extensive refurbishment of the roof was scheduled by English Heritage, part of a £1 million restoration project. Water ingress through the roof was affecting the structure, fixtures and fittings below.

The castle’s strategic placement at the seaward end of a shingle spit that extends 1.5 miles into the Solent has meant that it has always been in use. It housed Charles I in 1648 before his trial and execution, it played a critical role during the Napoleonic wars and, most recently, it defended the South Coast against the Axis forces during World War II.

As a result, the castle has undergone countless additions and alterations since it was built in 1544, most significantly with two enormous armoured sections added to each side of the fort in the 1870s. These alterations, combined with the castle’s hard-to-reach location, meant added complexity for any contemporary refurbishment.

The work on the six-month project included significant asphalt repairs throughout the West Wing’s roof, while the roof on the East Wing was completely stripped, then laid with 150 tonnes of sand and cement screed under 300 tonnes of IKO Permaphalt mastic asphalt. Concrete repairs were also made to some structural cracks on the East Wing. The majority of the work was carried out on a steep fall of 20% from the gun emplacements.

All parties – including English Heritage, main contractor Heritage Building and Conservation (South) Ltd., roofing specialist Infallible Systems, and IKO PLC, which supplied the mastic asphalt – had to work closely together from initial specification to final sign-off to ensure like-for-like replacements of the original materials. Plans had to be continually adjusted at short notice as variations in the materials and details were uncovered.

A polymer-modified mastic asphalt, IKO Permaphalt offers completely seamless waterproofing with long-term durability and stability across a wide temperature range. Its ease of installation and versatility are perfectly suited to complex, hand-laid projects making it ideal for the detailing the Infallible team had to do around the castle’s upstands, downstands, vertical, capping, drips and gutters. The only part of the roof that wasn’t worked on was the original Henry VIII round tower!

IKO’s experience with high-profile heritage products, including Westminster Cathedral, St Paul’s Cathedral, the Tower of London and Dover Castle, proved to be a major benefit to the project, combined with the expertise of the contractors who specialise in historic work. IKO provided in-person technical support throughout the laying of the castle’s new roof to field questions from the roofing team, offer progress reports to Heritage Building and Conservation and English Heritage, and ultimately check that the work was to specification. IKO was able to give a comprehensive, single-point guarantee covering materials, workmanship and design.

Castle Challenges
The project had more than its fair share of challenges. Firstly, the castle remained open to visitors throughout the project adding an extra planning element to the safe execution of the works.

Secondly, the unique position of the castle meant that access was limited to ferries, and pedestrians via a 1.5 mile gravel spit. Materials and waste had to be transported by tractor along the spit and then lifted on and off the roof by telehandler – including three 2-tonne asphalt ‘cookers’ which were used to prepare the IKO Permaphalt. Everyone working onsite had to take the 20-minute ferry crossing to and from the castle, meaning work was more susceptible to delays than usual due to the often choppy conditions of the Solent.

And it wasn’t just the waters that caused a problem. Due to the exposed nature of the site, weather conditions were a constant obstacle to the progress and completion of the works.

John Chapman, Director of Infallible Systems, comments on the challenges: “Throughout the project the weather regularly fluctuated between baking hot sunshine and storms, with the team battling wind, rain and hail. But despite the weather, extremely limited access and busy site, the works were completed safely, on time and to a very high standard. Hurst Castle is back to its former glory!”

IKO and Infallible have been shortlisted for an NFRC UK Roofing Award in 2018 for their work on Hurst Castle, with winners announced on 11th May.

Zero Carbon
IKO is committed to protecting the environment and minimising the impact of its products. Its UK factories have achieved environmental standards ISO 14001 (environmental management) and BES 6001 (responsible sourcing of products).

The net carbon footprint of this project was entirely offset using internationally approved carbon credits.