Rockpanel at ground-breaking Passivhaus residences in South Wales

An enduring and pioneering team 

Holder Mathias were architects for the project. Operating throughout the UK and internationally the company has created projects of enduring value for over fifty years. About sustainability it says, ‘As a practice we strive to be good stewards of the environment, using our skills to develop designs that respond to clients’ needs, that reduce energy use and operational costs, that enhance ecology and biodiversity while improving the value of a place.’  

The council partnered with Willmott Dixon as main contractor, in part due to the company’s long and pioneering track record in delivering high-profile Passivhaus projects. These include Harris Academy in Sutton, the first Passivhaus secondary school, and the George Davies Centre of Medicine at the University of Leicester. They are also building the UK’s largest Passivhaus leisure facility, Spelthorne Leisure Centre in Surrey. The company is also a founder member of the UK non-profit Passivhaus Trust. 

A demanding and exacting construction process 

The homes are constructed to an ultra-energy efficient standard, consisting of very high levels of insulation, extremely high-performance windows with insulated frames, airtight building fabric and a mechanical heat ventilation system. There are also many checks and balances in play at every stage of the construction process in order to achieve certification overseen by the Passivhaus Institute in Germany. 

A collection of four RAL Design Colour System-matched surface designs were chosen for Rockpanel external facades across the two storey schemes, the predominate colour being a white, with vertical blocks of Atlas Red, Halite Blue and Moor Pond Green – face-fixed with colour-matched rivets. The landscape rectangular panels used with a paired back architectural palette of dark grey framed windows and matching doors under a simple, low profile ridged metal roof, achieve a sharp and unfussy contemporary aesthetic. 

Rockpanel derives its unique properties from the core of sustainable volcanic basalt stone wool used in its production. Bonded with an organic binder it delivers a highly resilient, weather, temperature and UV resistant facade, which remains virtually maintenance-free.  

The facade substrate at Trethomas and Trecenydd incorporate ROCKWOOL Duo Slab® insulation which achieves European fire class A1. This BBA approved insulation adds thermal comfort while reducing the transfer or external airborne noise and is made from the same stone wool used in the manufacture of Rockpanel.  

A commitment to sustainability 

Rockpanel’s Christine Rees Davies, “Part of the Passivhaus ethic is to maximise the energy efficiency of a building, which leads to the use of less natural resources. Rockpanel also takes its environmental responsibilities very seriously. Rockpanel is made from up to 50% recycled materials and has a verified life of at least fifty years but even when the time comes to remove the facade the panels can be fully recycled again and again to make new products with no loss of quality.” 

The breadth of surface finishes offered by Rockpanel is truly impressive. It encompasses Natural Woods, Metals, Stones, Brilliants and the phenomenon colour transforming Chameleon. The surface can also be routed to create bespoke patterns and imagery. They offer specifiers the freedom to realise their most ambitious designs knowing the completed facade will satisfy the most stringent fire safety regulations and stay looking as great as the day it is installed.