St Nicks

Centre for nature and green living

DIY upgrade of a 1920s semi

For Lyle and Natalie, who took part in 2021 York Open Eco Homes, reducing their carbon footprint has been the primary motivation for retrofitting their house. They’re very happy to enjoy other associated benefits though, such as a healthier home and financial savings. They’ve done most of the work themselves:

Prior to moving into the home, we installed insulation in the floor, walls and loft. In our selection of insulation, we looked for a low thermal conductivity, high recycled content and low VOCs (volatile organic compounds).

We used multi-layer foil insulation in the walls, as this type of insulation takes up the least amount of space with the lowest thermal conductivity value. On the exterior walls, we installed timber battens horizontally on the old walls, stapled the insulation to the battens, then vertical counter battens were fixed through the insulation to the horizontal battens, and finally new plasterboard was fixed to the vertical battens.

Lounge floor insulation stages

Lounge floor retrofit stages – from floor boards removal to insulating and redecoration

For the lounge, after removing lots of debris from under the floor, we installed a vapour barrier on the ground and rigid foil face polystyrene insulation around the foundation wall. We used a different type of multi-layer foil insulation as the first layer at joist level, we then added rock mineral fibre batts on top of the foil insulation. In the kitchen, approximately 80% of the slab had to be removed. Then to prevent rising damp, we added a vapour barrier, rigid foil face polystyrene insulation, and repoured the slab. As a final touch for comfort, we added an electric heated flooring system.

Loft cleaning

Loft cleaning

In the loft, we removed the old fiberglass insulation since it had become wet, dusty and less effective over time due to settling. We cleaned the loft using a hepa-filtered hoover prior to installing the new insulation. We installed a layer of rock mineral fibre insulation between the joists, and then a second layer of the same insulation across the joists creating a finished depth of approximately 400 mm. In the loft where the soffit of the roof meets the ceiling, we installed 50mm rigid insulation, which maintains adequate roof ventilation while reducing the thermal bridging in that area.

To ensure adequate ventilation throughout the home and regulate humidity, we have first fixed a mechanical ventilation heat recovery unit. The unit can be up to 80% efficient at recovering heat, while exchanging the air in the house with filtered air from outside.

YOEH2021 Lyle and Natalie's water tank and boiler

Hot water tank and boiler in a custom-made insulated shed

We insulated the heating and water pipes with a high-grade lagging to reduce heat loss during supply. The heat and water pipes along with the main water supply (originally lead) were upgraded to plastic. We opted for a gas hot-water boiler and an unvented stainless steel 203L tank installed in a purpose-built boiler room placed in the back garden. This combination will ensure an ample hot water storage for heating and water supply with the added value of future proofing the systems. Our goal is to move to a heat pump within 5-10 years, but maintaining a gas supply line also allows for the possibility of one day using Hydrogen. We sourced antique cast radiators mostly to suit the period of the property. However, the larger cast radiators should also function better with a heat pump system due to the larger surface area and lower continuous flow rates.

To further reduce our energy demand, we changed the gas hob to an induction hob. Any new (or slightly used) appliances purchased for the home have an energy efficiency rating of A+ or higher. In addition to making our home more energy efficient, we opted for more sustainable purchases in the finishes as well.

Eco homes visitors inspecting the lino flooring

Eco Homes visitors inspecting the lino flooring

Fortunately, the flooring had been removed from the house prior to our purchase. While a popular choice, we did not want carpet in our home due to our issues with asthma and past problems with indoor allergens. Our house now has a mix of linoleum and cork flooring. Both types of flooring consist of natural renewable materials, maintain a healthy indoor environment, and range from carbon neutral to carbon negative. We used clay-based paints with very low (essentially zero) VOCs. We debated oak or bamboo for our kitchen worktops. Oak has the benefit of being local and from certified sources, but Bamboo as a fast-growing grass still seemed to be the more ethical option.

Upcycled arm chair

Upcycled arm chair

In our purchasing, we try to buy used as much as possible, but if we need to buy something new, we buy products with recycled content and/or made from renewable materials. We also used Facebook marketplace and free cycle to ‘recycle’ anything removed from the home. For example, some of the old kitchen cupboards are now in the Farming Museum’s volunteer kitchen. Once we have completed our home retrofit, we plan to nature-scape the front and back garden by replacing the gravel and concrete with native pollinators.

If you’ve got any questions about this home, feel free to get in touch with York Open Eco Homes organiser Ivana ( who can relay them if unable to answer directly.

This page was last updated 6 Dec 2021