New roof the icing on the cake for revamped hospital

Haselmere Hospital undergoes refurbishment, starting with new roof structure

Haselmere Hospital now has a new roof as part of a larger revamp scheme

Refurbishment work is underway to upgrade facilities at Haselmere Hospital in Surrey.

The building was originally constructed in the 1920s and the first phase of the work has included a new roof as well as replacement gutters and fascias, new windows and the provision of new external fire escapes.

The upgrade programme we have started really enhances the long-term viability of the hospital as it will prolong the life of the building and help NHS Surrey to deliver on its carbon reduction targets

Gordon Day, estates project manager at NHS Surrey, said: “The upgrade programme we have started really enhances the long-term viability of the hospital as it will prolong the life of the building and help NHS Surrey to deliver on its carbon reduction targets.

The design has taken into account the age of building and has been sympathetic in the materials used. For example, the new fire escapes have enabled us to utilise the second floor, which had been unoccupied for several years, and the new insulation will reduce our running costs.”

The roof was replaced as part of a project led by consultant, GVA Grimley. The company opted for a combination of foam board and TLX Gold, a combined multi-foil insulation and breather membrane from Web Dynamics.

The chosen solution will not only enhance the thermal performance of the building, in line with current building regulations, but will also minimise any changes to the roofline to ensure the building remains in keeping with the rest of the hospital campus.

Significantly, the specification considered clinical factors in addition to the maintenance requirements and thermal performance benefits. After considering two other multi-foil products, the hospital opted for TLX Gold as it was the breathable option, removing any risk of condensation and thereby contributing to the hospital’s infection control regime.

Effective insulation needs to trap warmth in the building while enabling moisture to escape, otherwise there is a risk of condensation. This is particularly problematic in a hospital setting where condensation can lead to growth of mould and fungi

John Payne of Web Dynamics said: “Effective insulation needs to trap warmth in the building while enabling moisture to escape, otherwise there is a risk of condensation. This is particularly problematic in a hospital setting where condensation can lead to growth of mould and fungi.

TLX Gold has three layers: a high-performance breather membrane, a core of PET wadding interleaved with reflective layersm and a film that reflects infra-red radiation back into the building. Because all three layers are breathable, no moisture is trapped in the building.”

The original roof for the hospital’s main building was closed boarding and felt with handmade clay tiles, typical of the appearance of several of the buildings on campus. Roofing contractor, West 1 Contracts, stripped the roofs back to the rafters, painstakingly removing the clay tiles so that as many of the original tiles as possible could be salvaged for re-use.

The hospital needed to remain fully operational while the roof upgrade was carried out and, despite the significant level of stripout required outside, inside the building it was business as usual.

Tony Brookes from West 1 Contracts said: “The existing roof was original to the building but, despite its age, the rafters were in good order. This meant that the ceilings could stay in place and the building could remain open to patients. The building’s occupants could hear us working on the roof, but the noise was relatively low level so disruption was kept to a minimum.”

The contractor laid 75mm thick foam board between the rafters, cutting it to the exact shape and size required for each section of the roof so that it fitted snugly between the rafters with no requirement for any fixings. The TLX Gold, which is supplied on a roll, was then laid over the rafters, leaving a pocket of air approximately 30mm wide between the foam board insulation and the combined multi-foil/breather membrane. Each section of TLX gold was taped together to ensure a complete covering of the roof and the combined multi-foil/breather membrane was then pulled taut to ensure there were no bulges before being stapled directly onto the rafters.

Payne said: “A non-vented air gap is an inherent part of the TLX Gold system as air is a very good insulator. By using conventional insulation and TLX Gold in combination, the hospital was able to maximise improvements in U-value while ensuring that any changes to the building were almost imperceptible.”

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