This detached 1950s house in Kingsdown on the Kent coast is undergoing extension and refurbishment to EnerPHit standard.

The house was original with just one small side extension that was only 1m wide, and barely of any use.  The house suffered from cavity wall tie corrosion, picked up during the building survey undertaken by Conker pre-purchase (we are chartered building surveyors). Being a simple geometric shape we realised the house had good potential for PH retrofit owing to a good form factor.

As a large extension was proposed we did not undertake a pre-start air leakage test, but experience with other cavity wall houses that utilise concrete block inner leaf leads us to be very cautious about airtight detailing.

The loft is being adapted to form a plant room, as the rooms are actually quite small and do not leave enough space for a combined utility and plant.

The extension is designed using Conker’s favourite I joist NIPPS system, this is extended around the whole building forming the external wall insulation.

German triple glazed windows are being used in conjunction with external retractable Venetian blinds, coupled with a first floor roof canopy for additional solar shading.

Existing floors have been broken up to allow for insulation and underfloor heating, and continuity with the new extension floor. MVHR is installed covering the whole house, heating is provided by a heat pump. A large PV with battery storage is being installed due to the relatively remote location.

Air tightness has been detailed very carefully using internal plaster as the principle layer.

The property will be open to the public for the Passivhaus Trust Open Days on Saturday, 8 November 13.00 – 14.40. To book you place click here