A StoTherm Vario K external wall insulation system has been installed on a large nursing accommodation unit at Addenbrookes Hospital, near Cambridge, where it has improved thermal performance standards and also helped the structure blend visually with the adjoining buildings. 

“Although the Harston House building has a brick construction, it was unsuitable for cavity wall insulation due to uneven cavity sizes and various cold bridging issues caused by the concrete floor slabs,” comments Sto’s Account Manager, Ian Sired. “However, our StoTherm Vario K system provided the perfect solution to help achieve the necessary degree of thermal insulation.  As it’s applied externally, it also does not infringe on the building’s internal spaces.”

“We first considered the StoTherm Vario system for this project because we were very familiar with the render systems which Sto supply,” explains Gavin Cowling of project architects Kendall Kingscott. “It was obvious that this solution would achieve the required U-value, but there was also an important aesthetic consideration too.  We wanted to update the appearance of the building and bring it more into line with the newer buildings which surround it on the site. From the huge range of colour options which Sto offers, we were able to select a combination of green, grey, blue, turquoise, ivory and white finishes and that allowed us to achieve exactly the finish we required.”

StoTherm Vario is a high performance EPS insulation system which provides excellent thermal insulation, and thanks to the mineralic reinforcing coat combined with well-designed fire stopping details, also meets stringent fire safety requirements, even on buildings such asHarston House. It is ideal for either new build or refurbishment projects, and in this instance, it was installed using Sto-Turbofix – a single component, polyurethane-based adhesive which offers a quick, clean and cost-effective method of application.

The reinforcing coat was StoLevell Duo Plus, which was primed before a finishing decorative coat of StoSilco K silicone resin render was applied. The high-performance silicone render provides additional resistance to weathering and water penetration, and reduces the likelihood of algae growth and soiling of the surface.

“The end result is excellent,” concludes Gavin Cowling. “Sto’s authorized applicator was Retrofit UK Ltd of Cambridge, and they did a first-class job. Sto themselves also made numerous site visits and provided whatever support we required, and between us we helped bring this important building back up to modern standards.”

Harston House is owned by Cambridge University Hospital Trust and operated by Sanctuary Housing.