No-fines concrete housing insulation scheme (CP779)

No fines concrete houses are houses that have walls constructed from in situ cast concrete that does not contain the fine aggregate that is usually mixed within the concrete. This means that the larger aggregate (gravel of 10 20mm in size) is bound by a cement slurry coating. As such, connected voids are found throughout the walls. The result of this is that these house types do not behave like other solid wall properties in relation to heat retention, air tightness and resistance to moisture. This project seeks to address heat loss and air tightness issues in a group of such properties for The Riverside Group by testing an incremental set of retrofit measures in combination and measuring their impact on heat loss and airtightness, thereby developing a set of solutions that potentially reduces the incidence of fuel poverty. It also seeks to change the way retrofit projects are approached, delivered and monitored.

The project had the following aims:

• Secure a deeper understanding of the possible range of retrofit improvements that may be made to no fines housing (an often neglected typology for housing retrofit, due to their ‘hard to treat’ nature).
• Using a matrix of possible small measure improvements understand which difference combinations of products can be used to create a tailored retrofit approach to no fines housing.
• To increase thermal comfort for residents and reduce their energy bills.

These aims will be tangibly demonstrated by trying to achieve the following targets:

• Reduce Air Change Rate from >16 M3/(H.M2) to below 10 M3/(H.M2) 1
• Reduce Heat Loss, Damp and Cold Bridging through carful retrofit detailin
• Reduce fuel poverty and incidences of Asthma and other environment related health issues
• Increase longevity of building fabric i.e. reduce maintenance legacy particularly with respect to damage caused through damp
• Produce a pattern book of options for houses in different states of maintenance and retrofit within the typology.