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Restoration of heritage roof using traditional craftsmanship

By Published On: June 25th, 2022
Heritage roof restored by PMAC

PMAC are onsite taking care of the complete restoration of a beautiful villa style Georgian house that dates back to 1820. The client is taking every step to restore the house using only original methods and materials, replicating the best of Georgian craftsmanship.

Heritage roof restoration:

Philip Edwards is a Master Craftsman specialising in Heritage roof restoration. Philip partnered with PMAC to oversee the complete restoration of the Georgian roof which was in very bad repair, was leaking and missing many slates. The initial task was to strip the roof of a layer of bituminous tar and hessian. This would have been added in later years when slates may have gone into dis-repair. It was added to waterproof the roof and to prevent the slates from slipping. Unfortunately the original Bangor Blue slates underneath couldn’t be saved however the roof structure was very well preserved.

Hemp Crete insulation:

We then saved as much of the existing timbers as possible, most were in very good condition except where the roof had been leaking for many years. These beams had to be replaced.

Hemp Crete was the insulation material chosen, thanks to its amazing thermal insulation properties but also because of its sustainability and environmental friendly credentials. Hemp Crete is a carbon negative material. Hemp Crete, which is a mixture of hemp shives mixed with lime and water is a natural insulator which keeps interior temperatures controlled, no matter the season.

The new structure was tied in to secure the original lathe and plaster ceilings

Recreating copper valleys, hatches and flashing:

Work was then moved off site to work on the copper fittings. Chimney flashings, access hatches and valleys needed to be fabricated. Copper was chosen as this was the material originally used on the roof , a very common practice in Georgian architecture. Copper was traditionally used because of its durability and resistance to corrosion, as well as its prestigious appearance and ability to form complex shapes. For century’s craftsmen and designers harnessed these attributes to create aesthetically pleasing and durable roofs. Copper develops a natural patina (green coating), which protects from corrosion, the patina layer also has the ability to self heal.

A passion for preserving heritage roofing skills and traditions:

Copper chimney flashing, access hatches and valleys were all expertly fabricated by Philip in his workshop. Philip is an ardent believer in preserving and practicing heritage skills and craftsmanship. He is passionate about Georgian traditional roofing skills which more often than not have proven to be much more durable than modern day roofing solutions.

Linseed Oil as a sealant:

Boiled linseed oil was used as the sealing material in the welted seams, again borrowed from the Georgian tradition and proven to be far more durable and reliable than modern day silicon sealers.

Installation of Copper fixings, Welsh slates and Lime Parging:

Philip and his team then moved back to site to install the first copper access hatch and the chimney flashing. New Bangor slates were sourced and fitted. Keeping with Georgian methodology, the underside of the slates were treated with lime parging. Parging comes from the French term “par jeter”, which literally means to throw all over. The underside of the slates were treated with the lime plaster, which acts as the breather membrane. The lime plaster fixes the slates in position like a second skin and absorbs any condensation that might occur. This is Heritage Georgian roofing at its finest.

The original ridge tiles, dating from 1820 were in great condition and were re-bedded using sand and lime. A 25 mm seam separation joint was installed to both neighbouring properties and the ridge.

This is one of the finest examples of the restoration of a Heritage roof you will probably find in Ireland. This roof is preserved for century’s to come and it would be wonderful to think the same methods might be used in the future to conserve this beautiful structure. That of course won’t be necessary for another 100 years or so.

Copper flashing

Copper flashing and original ridge tiles restored

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