Retrofit of 1960s Dormer Bungalow in Chepstow

Kingswood is a 1960s dormer bungalow that was suffering from problems inherent in dormer houses of this era. When the heating wasn’t on the whole house quickly chilled and without the replacement uPVC windows being left open, the house suffered from poor air quality and damp.

CRSH were appointed to to provide designs to upgrade both the accommodation and performance of the house. Working with a local carpenter and sawmill, we came up with a Larsen truss system to add 150mm of insulation to the outside of the walls. This construction system was also used to extend into the roof to create a very large new dormer on one side of the house. Completed with triple glazed timber ‘frameless’ windows, a MVHR system and thermal store, the clients can now watch the winter storms blowing in over the Bristol channel, without having to switch their heating on.

Upper floor completed 2018

Retrofit of Arts and Crafts House in Abergavenny

Located in a conservation area in Abergavenny, this is an attractive and well designed Arts and Crafts semi detached dormer bungalow with large well proportioned rooms. The clients bought the property to downsize from their new build rural eco home, but did not want to compromise the thermal comfort they had grown used to.

They approached CRSH to assist them in extending and retrofitting the property. Although they originally expected to have to build an extension to give a large family kitchen dinning living room, we found a way to alter the existing internal layout to provide this space without the need for an extension, as well as creating a new ground floor wet room.

Being in a conservation area, only subtle changes could be made to the exterior so all other opportunities for increasing thermal performance have been maximised. The existing floor slab was removed and the sub ground dug away. This allowed for 250mm of insulation and a new floor slab with under floor heating. The large upstairs rooms allow the addition of a Larsen truss to increase the roof insulation zone. The existing uninsulated dormer sides are also being rebuilt to add insulation without compromising their appearance. All the windows are being replaced with high performance timber framed triple glazed units designed to match the remaining original windows, and a MVHR system fitted.

Due for completion 2020

It is now widely recognised that to bring carbon emissions to an acceptable level, the energy performance of existing buildings is going to have to be drastically improved. We have the expertise to design energy upgrades for your building without unintended consequences, and with a respect for the balance required when working with a historic building or in a conservation area.


We were expert peer reviewers for the UK Gov Retrofit for the Future project and fellows of the Centre of Refurbishment Excellence. We have also carried out detailed reporting and monitoring projects on retrofitted homes for Housing Associations and Government bodies.

Retrofit Projects