A three-bedroom, solid-wall, semi-detached property much in need of renovation: The house was suffering with black mould in most rooms due to the cold



We are proud to have won the award for Regional Small Scale Project of the Year at the 2018 West Midlands Regional Energy Efficiency Awards for this renovation.


A three-bedroom, solid-wall, semi-detached property much in need of renovation: The house was suffering with black mould in most rooms due to the cold surface temperatures and high humidity levels. The heating bills were also a concern to the homeowner. There was a major heat loss area where a conservatory had been added to the house in the 1950’s and absolutely no insulation.

The homeowners wanted to enlarge the home significantly and were interested in energy-efficient building materials, in particular solid wall insulation and Porotherm walling system.


The solid walls were a major factor. The leaking bay window of the snug was insulated internally and the front and side of the building were insulted with 90mm EPS graphite boards and a white render finish from Saint Gobain Weber. The new solid floors were insulated to accommodate an under floor heating system and the remaining suspended timber floors were improved with further insulation. The loft was also insulated in line with building regulations to create a cold roof and internal wall insulation systems applied to the curved parts of the ceilings to ensure no cold-bridging. New windows were fitted and were suspended outside the original frame of the building – again, to eliminate cold bridges and draft-proofing tape was used at the reveals to ensure better air permeability.

We wanted to eliminate the black mould and condensation problems. We proposed an element of heat recovery and an EnvrioVent whole-home positive input ventilation system. This would use solar gain from the loft on warm spring and autumn days and distribute it into the property, to reduce heating and keep the humidity levels under control. Single room heat recovery units were installed downstairs to extract moisture-laden air and also conserve heat.

Walling System
The old conservatory was removed to make way for a larger double-storey extension that would add an additional bathroom, bedroom, utility room and create an open living, dining and kitchen area. The extension was constructed without a cavity using 365mm Porotherm clays blocks that had an excellent R-Value. A white, render finish was applied to match the EWI at front and rear.


The energy-efficiency has been maximised, with incredible energy savings of around 40% per annum. The property now has an adequate number of air changes to ensure the air quality is best and condensation/black mould has been completely eliminated. The value of the property has increased significantly so the initial costs are well-justified.

We are extremely delighted with our new home and feel very comfortable. Our heating is on for minimal time periods as it so well conserved by the insulation. We were offered excellent, professional advice and I feel we have really benefitted from this. We would highly recommend Six Star for similar projects.

I am able to verify energy savings through utility bills.