Truro cathedral

The fundamental problem…

All old buildings require maintenance and repair, but here in Truro we have a particularly difficult problem. The Bath stone, used for decorative carved work, has not stood up well to the Cornish climate, it has crumbled and disintegrated. Because all the replacement work is at high levels it is a very expensive process.

At first our partners in funding this work, English Heritage, insisted we replace like with like, a course of action our Cathedral Architect couldn’t support. So we entered into a Research Project carried out at Hallam University in Sheffield to see if we could identify a similar stone, but one of greater durability.

The Research Project

This Project entailed building walls of various stone blocks in accelerator and simulator chambers to test the durability of stone under simulated ‘Truro micro-climate’ conditions. The results were carefully analysed by English Heritage and a panel of experts. The outcome was that our particular Bath stone (Stoke Grand Base Bed) was unsuitable for use in Truro, and that a Cotswold Stone – Syerford was identified as the best replacement stone. The Research Project cost some £20,000, and we are indebted to English Heritage for an 80% grant towards it. The photo on the right shows the type of damage done to the stonework..

The Solution

Using Syerford Stone we have begun a fifteen year programme to replace the failing Bath Stone with a material we believe will not alter the appearance of the Cathedral but will be more durable. The new Syerford stone is carefully carved and filled to replace defective and weathered Bath stone. This restores some of the finer details created by the original architect, John L Pearson.