Herefordshire Housing Association


Merriman Roofing


Housing Stock Upgrade




Recently, Herefordshire Housing Association, part of Connexus, announced plans of a five year project with the aim of improving the energy efficiency levels of its entire housing stock, which includes over 500 Cornish type houses across Herefordshire. 

Many of these homes were built between 1946 and the 1960’s as a ‘temporary’ solution to the post-war housing crisis and they are easily recognised because of their distinctive Mansard roof structure. While they were intended to be temporary, these Cornish-type homes are still inhabited by thousands of people across the country. 

Herefordshire Housing Association have invested £3.5 million over 5 years to increase energy efficiency in their existing properties. 


The contractors, Merriman Roofing and distributor Encon Insulation were given the target of improving the thermal performance of this insulation in the Mansard roofs to a u-value of 0.30 W/m²K, while minimising the disruption to residents which wouldn’t have been possible using traditional means. 

Because the houses were occupied, all improvement works needed to be carried out from the outside to minimise the impact on the occupants.

Unfortunately, due to the Mansard roof which covers the second storey of the building, it’s difficult to significantly improve the energy efficiency of the homes using traditional materials and tools, with a u-value target of 0.30 W/m2.K, traditional insulation was too thick.

In the past, efforts to improve the insulation of the Cornish-type homes have been limited by the design of the roof. Achieving a good fit within the timber frame using externally applied options has proved to be challenging due to the narrow cavity between the interior wall and the exterior roof and applying products from inside can typically be disruptive and intrusive for occupants.


To overcome this issue, the companies sought our expert advice and services to provide cost-effective insulation which could be quickly and easily applied from the outside of the property and which met their targets for thermal performance.

After visiting the houses that required new insulation, our experts came to the conclusion that our SuperFOIL SF40 multifoil insulation would be the perfect solution to the problem. Because SF40 measures to be just 65mm thick when installed, it was a suitable fit for the unusual Cornish-type properties and their distinctive roofs which only allow a narrow space for insulation. 

Working with, Herefordshire Housing, Encon and Merriman Roofing Contractors Ltd, we have supplied enough insulation to provide for over 500 houses, improving heat retention in the winter and energy efficiency throughout the year. 

SuperFOIL worked very closely with Hereford Housing Ltd and Merriman Roofing Contractors Ltd to offer a bespoke solution. SF40 was up to the challenge achieving 0.26 W/m2.K, significantly exceeding their target value. A single layer of SF40  provided maximum performance, minimal thickness, improved air-tightness, radiant barrier, huge cost savings and less disruption to the residents.

Director of Merriman Roofing, Mike Merriman, said: 

“SuperFOIL’s SF40 multifoil insulation was the only product on the market that could do the job and we’ve used it on every one of the 500 homes to great effect. Using SuperFOIL, we’ve exceeded our target and cut the u-value to just 0.26 W/m²K. 

“The SF40 insulation has been quick and easy to install, enabling us to complete the work with minimal disruption to residents. The upgraded houses should cut residents’ heating bills significantly and they’ll be much more comfortable in their homes over winter. I’m really pleased with the results.”

National Sales Director of Encon Insulation, Steve Clarke said:

‘’Encon were proud to be involved with the Herefordshire Housing contract. SuperFOIL were very helpful in providing calculations to ensure we achieved the correct specification for the contract. 

“It was great to see modern construction materials being used on the traditional Cornish type properties. The products worked well and were easy to install for our customer, Merriman Roofing.

“SuperFOIL were helpful throughout the project and the products performed well.’’