The National Martime Museum, Greenwich

Project: The National Martime Museum, Greenwich

The National Maritime Museum welcomes over 1.5 m visitors a year and is part of the UNESCO Maritime Greenwich World Heritage Site.  The major new extension, named the Sammy Ofer Wing, has been made possible thanks to a massive £20m donation by shipping magnate and philanthropist Sammy Ofer, who served with the Royal Navy in WWII.

The design of the extension includes a new entrance, new exhibition spaces and new visitor and study facilities.  It is on track for opening in 2011 and is expected to achieve a BREEAM ‘Very Good’ rating for sustainable design, with Jablite insulation products playing a key role in delivering that.

The main contractor Bovis Lend Lease, responsible for designing the package that would provide the waterproofing and insulation, appointed Rock Complete Waterproofing to undertake the work.

Managing Director, John Walsh, who served with the Royal Navy for ten years, had a very personal reason for being particularly pleased to be involved in this prestigious project: “As an ex Naval Serviceman, the fact that that we will be providing watertight integrity to this building, which is to protect the display of Nelson’s uniform brings home the importance of the task.”

Rock has the technical expertise and immense experience to take on this kind of high profile project. John Walsh explains exactly what the challenges were: “The main issues for the roof were twofold.

“Firstly to provide a watertight system that was sufficiently robust to provide peace of mind to the clients and an overall build up that could accommodate drainage whilst maintaining the architect’s desire for a continuous stone slab finish.

“The only truly robust system which could meet the criteria laid down was Rock’s own Flexiphalte triple protection system and this was instantly recognised by the Client and main contractor alike.”

The next choice was the insulation to the warm roof area, which had to achieve a U value of 0.15 and to demonstrate extreme longevity when buried. This U-value, in excess of the building regulations, because of the environmental criteria of the whole scheme, has been easily achieved. In fact, an even lower U-value has been reached by Jablite Flat Roof Tapered (FRT).

Lead architect on the project, Alasdair Travers, of Purcell Miller Tritton, explains: “The Jablite FRT performed a dual role, not only as an insulator, but also as structural void filler.  The difference between the basement roof and the level we needed to reach for the terrace needed to be appropriately filled.

“The solution was to use extremely densely moulded Jablite FRT, that would have the compressive strength to withstand the weight of a fire engine ─ a key factor in the overall design of the building ─ without damage to the stone slab finish or to the structure.

“The combination of the thickness of material used to fill the space and the unusual density mean that we will exceed our own target U-value by some margin,” adds Alasdair.

The Jablite FRT supplied was moulded to a density of EPS 500, the typical density being between EPS 100 and EPS 200, depending on the performance needed. The EPS 500 density is an unusual, but extraordinarily robust option that provided the compressive strength necessary for the café terrace.

John Walsh summed up the choice of Jablite FRT for the Maritime Museum project: “Jablite were able to meet all the necessary requirements with their product.

“We found the technical support provided by Jablite to be excellent, their input was comprehensive and timely and we would have no hesitation in using their products again.

“In fact, we would very much like to see the Jablite range of insulation products increased and made readily available in order that they can provide a viable and commercial alternative to the insulation products that currently dominate the insulation market,” he concludes.