Cornish Type 1 – Caerphilly

This project, on behalf of Caerphilly County Borough Council, consists of various phases. These phases covering numerous housing estates are being rolled out over a number of years.

These particular Cornsih Type 1 PRC house types with a medium pitched, hipped roof are designated defective and are renowned for problems associated with severe horizontal and vertical cracking of the PRC columns, cracking of the horizontal PC panels and the first floor ring beams and for high rates of carbonation.

In close collaboration with the system installers, Joyner PA (Cymru) Ltd, the Wetherby Insulated Render System was used on the outside fabric of the building.  This system incorporated 60mm Phenolic insulation, in addition to 10mm EPS insulation which was used between the concrete columns and was finished using the Wetherby Brick Slips in ‘Miramar’ and ‘Estela’.

The system used not only improved the property’s U-values from 2.04 W/m²K to just 0.31 W/m²K, but more importantly will help to reduce heating bills and carbon emissions in the future.

In addition, because all Wetherby systems are designed to be strong and weatherproof, water ingress and dampness were also eradicated.

Project Type

Domestic Refurbishment – Non Traditional Housing


Caerphilly County Borough Council

System Installer

Joyner PA (Cymru) Limited



Michael Dyson Associates (Consulting Engineer)