Sto Ltd has provided a comprehensive insulation solution for a ground-breaking healthcare project built in Northumberland.

Innovative offsite construction techniques were used to create the new £15m extension to the Northumbria Emergency Hospital in Cramlington, with a combination of StoTherm Mineral external wall insulation system and Sto render finishes being specified to help achieve a striking appearance for the building.

The new 3-storey building is constructed from almost 300 modular units which were built offsite and then installed by The McAvoy Group of Lisburn – a strategy which reduced the anticipated construction schedule by over 50%.

“This is a very innovative approach to creating this type of advanced healthcare facility and it required very close liaison between ourselves, The McAvoy Group and Sto, to provide an insulation solution that would be effective and totally reliable,” says Stephen Hatcher of P+HS Architects.

The StoTherm Mineral system incorporates mineral fibre insulation boards and reinforcing coats and meshes to deliver an extremely durable insulation solution with unrivalled fire protection and high thermal performance.

“The Sto system could be installed once the modular units were in place,” adds Stephen. “It offered us a great combination of thermal performance, flexibility of installation and fire protection, all of which were especially important considerations on this project.”

The modular nature of the new building’s construction meant that a great deal of detailing work was required on the insulation solution, especially on areas such as the interfaces between the individual units.

The intention to align the three floors of the new building with those of the existing hospital premises also demanded considerable flexibility from the insulation. This was combined with a need for the insulation to help the buildings meet strict NHS fire performance requirements, but the Sto solution was able to satisfy each of these requirements.

“The modular units have a timber-frame construction and include cement particle sheathing boards, to which we applied the StoTherm Mineral external wall insulation system,” adds Alan Rees of Eco Rend North East who installed the Sto system.

“Using Sto-Rotofix Mini spiral fixings, this enabled the external wall insulation to be installed quickly and easily, which was important given that this was a complex project being built on a live hospital site.”

All Sto-Rotofix mechanical fixings can be viewed after installation and easily adjusted to provide a perfectly level surface ready for rendering. “This was another key benefit on this project,” adds Alan. “The fixings allowed the creation of a drained cavity, but one which could be sealed around the doors and windows. It also enabled us to accommodate the joints between the modular units and ensure effective thermal insulation, while still creating a smooth and seamless exterior surface once the job was complete.”

The design of the new building incorporates a number of areas with curved external surfaces, and Sto provided a Lamella mineral fibre insulation solution which allowed the architects to achieve their design aims without compromising the thermal performance.

Once the Sto insulation system was installed, the project was completed with the application of a reinforcing mesh to add extra strength, StoSilco and Stolit renders and StoColor Silco façade paint. These products provide high levels of resistance to the effects of the weather and the growth of algae and fungus, plus excellent CO2 and water-vapour permeability which allows the wall construction to breathe and dry out.

Operated by the Northumbria Healthcare NHS Foundation Trust, the new building houses one of the UK’s first purpose-designed Ambulatory Care units plus a host of purpose-built facilities which are dedicated to providing emergency care on a round-the-clock basis.