Tŷ Newidiadau

About this project

Tŷ Newidiadau is a small development of affordable new homes situated in the Welsh village of Garndiffaith in Torfaen. Built by ENGIE for housing association Bron Afon, the project was set up as a pilot to evaluate alternative modern methods of construction, using early contractor involvement.

Previously known as Ty Rosser Gwyn, the project was funded by the Welsh Government’s Innovative Housing Programme which aims to increase the supply of affordable housing, support new housebuilding approaches and technologies, tackle fuel poverty with energy efficient homes and develop and support local industry.

The properties were designed for residents under the age of 35 and consist of three separate buildings each containing one one-bedroom flat and three two-bedroom flats.

Comparing three construction methods

Tŷ Newidiadau consists of three two-storey apartment blocks on one site, built using three innovative timber-based methods of construction: ModCell Tam, ModCell Core and SIPS. As a result, Bron Afon will be able to compare the strengths and weaknesses of different construction solutions and to carefully monitor each of the properties post-construction.

Straw bale technology

The first two blocks were built using two different thicknesses of straw bale technology from ModCell:

• ModCell Tam – Manufactured structural panels using carbon capturing materials including compressed straw board, straw insulation and timber. It can reduce heating bills by up to 90%.

• ModCell Core – A multi award-winning modular building system using prefabricated structural straw bale cladding panels. The system utilises thermal insulated straw bales and wood to enable high performance, low energy buildings built using sustainable materials.

 The prefabricated panels are made of straw and timber resulting in a factory finished, fully closed dry lined system. The timber panels are filled by hand with waste straw that would otherwise be burnt off.

Structural insulated timber panels

The third block was constructed using foam-filled structural insulated timber panels (SIPs) from Seven Oaks Modular. The Triso-warm timber frame panels are filled with polyurethane foam which is pumped into the casing. The system provides high levels of thermal performance and air tightness and low levels of waste. Off-site manufacturing coupled with fast onsite installation saves on costs.

Rapid and straightforward construction

Once the groundworks were complete, all three blocks were constructed within just one month. Access was challenging due to the location of the plot and with substantial timber panels to manoeuvre into place, a crane was needed to build each of the properties.

However, despite the different types of structural panel, the construction method for each block was very similar, with similar fixings for each. In addition, the same material was used to clad each of the blocks to enable a direct post-occupation comparison.

Monitoring energy usage post-occupation

The tenants moved into the properties in Spring 2019 and their water, gas and electricity usage will be monitored by the Welsh Government for a minimum of twelve months. In addition, a weather station will be installed to assess how well the homes perform over the year as the weather fluctuates.

Initial thermal efficiency tests on the buildings proved very positive and specifically, the project will monitor:

• energy efficiency and heat loss
• energy usage (electricity, water and gas)
• hot water output
• thermal imaging
• tenant lifestyle survey.

Further Information

Images: Bron Afon Housing, ModCell