Timber Condition Survey of the northwest transept roof of Canterbury Cathedral.

EBS Ltd recently carried out a Timber Condition Survey of the northwest transept roof of Canterbury Cathedral.

The oak roof was generally in good condition, although some water penetration had resulted in wet rot decay to a number of rafters, purlins and wall plates.  

Woodworm and Death Watch Beetle had damaged the sapwood of many of the timbers but this was generally not structurally significant as the sapwood made up a small cross section of the timbers.  

However some of the damage was found to be structurally significant in areas of historic water penetration.  These areas were tested with a RESISTOGRAPH decay detection drill to assess and quantify the full extent of decay.

Some limited repairs will be required to strengthen the timbers.  No chemical treatment was recommended as the decay was not active in most instances and any areas of active insect damage will be removed when the repairs are carried out.