Dry Rot treatment at School Chapel, Sidmouth

Background to Case Study

Our Timberwise team in Sherborne were called out to inspect a residential flat within the grounds of a school for a suspected case of dry rot. Adjacent to the flat was a chapel, a substantial period building with external walls constructed with a mix of random stone and brick. On the initial survey, our surveyor was called upon to inspect the flat where the owners suspected a dry rot outbreak. Following the survey, Timberwise were instructed to treat the property for dry rot.

Prior to Timberwises involvement

Whilst carrying out the dry remedial works within the flat the adjacent chapel was also inspected for signs of dry rot as dry rot can grow over significant distances to find a food source. Upon this further survey, our surveyor identified further signs of dry rot within the roof structure of the chapel. The opportunity was taken to erect a scaffold tower to gain access to inspect the main roof area of the chapel. A small amount of the close boarded timber was also stripped to determine if there was an outbreak behind the roof structure as well.

The survey was carried out on the chapel roof which had a barrel vaulted ceiling formed from principal timbers and then supported by stone. In addition, smaller secondary timbers between the principal curved sections were also inspected. It was evident, when stripping out a section of the close boarded timber there was evidence of a dry rot attack. This attack had affected the first two principal timbers towards the rear left corner of the chapel as well as affecting the secondary, curved timbers.

There was no evidence of a dry rot attack affecting the main frame timbers, purlins or rafters of the main roof structure of the chapel, although dry rot was present within the exposed brickwork of the external wall. Significant water ingress into these areas was evident as there was evidence on the plaster finish of deterioration and salt contamination.

Whilst carrying out the external inspection numerous defects within the roof and flashings could be seen. Also, the size of the guttering used on the main roof was a concern as from the ground inspection, it was clear that ordinary domestic capacity guttering had been used but due to the pitch and size of the roof area much bigger gutter was needed to contain the flow of water. As a result, during periods of heavy rainfall rain water was overflowing from the gutter resulting in staining on the external wall directly below the guttering and causing penetrating damp issues within the property.To ease this problem, it was suggested that larger size rainwater goods be employed that could handle increased amounts of water.

Solutions and results

To remediate the dry rot outbreak, all defective timbers were replaced with pre-treated replacement timbers that matched the European Oak timbers previously used. All exposed masonry was cleaned down and treated with fungicidal fluid, any timbers exposed were also treated with fungicidal fluid within the main roof structure. In addition, all defected plaster on the rear walls of the chapel was removed.

Timberwise are specialists in treating dry rot problems in commercial properties and have over 45 years’ experience in the successful remediation of dry rot. To arrange a dry rot survey complete our on-line survey request form or call our team on 0800 288 8660

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