The Old Chapel, Nr Bradford Peverill, Dorchester DT2

Built in 1884 and converted to a residential house in the 1950’s, The Old Chapel is constructed of solid flint, brick and lime mortar walls. Whilst having plenty of character it is poorly insulated, cold and damp and in need of refurbishment! We are embarking on a programme of improvement and retrofitting with the objective of getting, as close as reasonably practical, to net zero and would be happy to share the experience and insights we have gained to date with others.

A key challenge has been to identify a suitable form of wall insulation. To retain the original aesthetics, only internal insulation was possible. The flint and lime walls present a particular challenge, the flint being highly conductive and lime mortar very porous and, to address the risk of interstitial condensation, a breathable system has been adopted based on the use of Multipor insulation boards. Manufactured in Germany and available in the UK, this system is inert and considered particularly suitable for historic and damp masonry. We have successfully trialled it in one room and now intend to adopt it throughout the house.

Other works completed to date include:

• Fairly conventional loft insulation including boarding out above it for storage

• Woodfibre/PIR insulation and creation of void ventilation in the sloping parts of the roof in the bedrooms

• Implementation of air tightness provisions in the room we have internally insulated.

• We are about to appoint a contractor to install PV solar panels, a battery and gateway (to provide an uninterrupted power supply in the event of a mains power cut) and hope this will be operational by the end of 2026.

Envisaged future works include the following, although we currently only in the early stages of planning these:

• Replacement of the ground floor, which is currently of suspended timber construction, probably with foamed glass and limecrete and reuse of the existing floorboards above this to retain the original character.
• Installation of an air source heat pump.
• Upgrade/replacement of the central heating system, including underfloor heating downstairs.
• Installation of new double glazed timber windows

Open to visit all year - please email dorsetgreenerhomes@gmail.com to make an appointment.