Johnstown Castle

Although there have been castles on this estate since the 12th Century, the current Gothic Revival structure was built in the 19th Century on the skeleton of the prior Norman castle. The rebuilding was undertaken by John Knox Grogan, brother of the prior owner Cornelius Grogan – executed for his role in the 1798 Rebellion. When the Crown restored the estate to the family in 1810 he immediately began a decades-long project to redesign the entire estate. The site is now managed by the Irish Heritage Trust and is open to the public year round.

Scope

 It was decided to refurbish all areas of the roof in a comprehensive and environmentally-sustainable manner. A faulty legacy flat roof installation was entirely removed, as were areas of compromised mortar and leak-prone sheet lead coverings.

Areas formerly covered in PVC and mortar were replaced with an extremely durable multi-layered mastic asphalt (Permaphalt). Slate roofs were completely rebuilt, replacing timbers and other substrates in strict adherence to conservation guidelines.  Slates were carefully reclaimed and reused on pitched roofs as well as being bedded in traditional lime plaster on vertical walls (see photo). The removed lead was reclaimed and used for new ridges, valleys and flashings (see photo). Ventilation and drainage was installed and/or repaired throughout. The towers and turrets were also resurfaced in asphalt after repointing. 

This comprehensive and environmentally sustainable re-fit has resolved long-standing leaks and drainage problems, The uniformly high standard of work means that plans for significantly increased community usage of the building can now move forward in confidence and safety.