Caol, Fort William
Client
Highland Council & Union Technical
Sector
Housing
Status
Completed
This whole house retrofit project for Highland Council implemented upgrades and energy efficiency improvement measures on 42 social housing properties and 12 private homes in Caol near Fort William. The mixed tenure project sought to reduce energy costs and make homes warmer for residents, while addressing the issue of fuel poverty.
The existing properties were two storey post war ‘Swedish Timber’ houses featuring timber-cladding on thin timber external walls.
As appointed Retrofit Assessors and Retrofit Designers, Carbon Futures was responsible for carrying out a retrofit assessment on the buildings. We developed a retrofit strategy and design to balance the challenges relating to moisture movement, thermal performance, fire regulations, budget, and occupant needs.
For the duration of the project, Carbon Futures worked closely with building standards, producing multiple warrant submissions to allow a rolling programme of works to commence on-site to suit the project’s funding deadlines.
During the construction phase, we provided technical site support to Union Technical in relation to specific detailing including thermal bridging details.
Due to the technical challenges posed by the existing construction and the specific location, thorough thermal, structural and fire-safety assessments were crucial.
Wall insulation options were also largely dictated by the requirements of the Domestic Technical Handbook and the need for occupants to stay in the properties during the work.
Initial energy modelling in SAP highlighted that the existing properties had SAP bands of D and E.
The retrofit design that was developed for most of the social housing homes includes:
Installation of External Wall Insulation (EWI) to have a significant impact on heat loss and reduce thermal bridging.
Verge roof extensions to ensure adequate protection from water ingress for the EWI.
Roof insulation top ups to 300mm in all properties with attention paid to roof ventilation.
New double windows and external doors with careful detailing to limit thermal bridging.
In line solar PV panels were installed on the roof.
Air source heat pumps were fitted to the rear of the houses that did not already have them.
High efficiency water storage cylinders and heating and hot water controls.
New dMEV ventilation with review of existing trickle vent and door undercut provision.
Removal of existing asbestos roof tiles and installation of new light weight roof tile to suit structural requirements.
New rainwater goods.
New canopies.
Properties that received the above suite of improvements now have EPC Band B rating.
Multiple funding streams, including Scottish Government EES:ABS, Energy Company Obligation (ECO) funding, SSE Renewable grant and Council Housing Capital budget were secured to enable the Council to have a wider impact and achieve economies of scale.
Highland Council
Balfour Engineering
