Damp Proofing a Castle

Summary

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  Before the cafe conversion

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  Newton 805 Newlath was ideal for treating the damp walls as it conformed with Listed Building requirements

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  The outbuilding is now free from damp problems and has been converted into a cafe

BBA approved Newton 805 Newlath used to treat damp in an outbuilding in this stunning 19th century castle, so it could be converted into a cafe. Newton damp proof membranes meet strict criteria for waterproofing listed buildings.

The Project

Penrhyn Castle is an enormous 19th-century neo-Norman castle in Snowdonia, North Wales, and stands as one of the most admired mock castles built in the United Kingdom during the 19th century. As a National Trust property, it requires extensive facilities for visitors. Penetrating damp affected the walls in this outbuilding and caused structural degradation.

The project involved transforming a former garage—originally the Castle brewery—into a new courtyard café. Penetrating damp had severely affected the brickwork and caused structural degradation, so the team required an effective damp-proofing solution. The damp proofing system needed to be acceptable for use in this historic building and meet strict requirements.

The Solution

To bring the outbuilding into a condition suitable for plastering would have entailed a lot of messy, noisy and disruptive work (needle gun, bush hammer, scabbler or cup brush etc.). This still would have had a damp problem to deal with. Dry lining was not an option as The National Trust did not want the very straight lines of plasterboard. They wanted to retain an appearance in keeping with the original lime plasterwork.

The team installed the Newton 805 Newlath damp proof membrane to the affected castle walls. The team finished the walls with a plastered universal one-coat plaster applied in a three-coat undulating build-up. This approach ticked all the boxes, producing a strong, dry, and authentic-looking wall finish that met all of the client’s requirements.

The Result

• Guaranteed protection for the new finishes against penetrating damp
• The team retained the walls’ undulating character for aesthetic authenticity.
• Newton 805 Newlath is sympathetic to the structure which conformed to The National Trust’s strict requirements
• The treatment is reversible so the wall can be returned to its original state if required in the future.

Finally, Newton 805 Newlath is ideal for damp proofing historic buildings, and contractors have used it in many historic properties, including the Houses of Parliament and Windsor Castle.