Floors Castle Roof Restoration Project (Update)

February has seen our first tentative steps into the Castle reroofing and high-level masonry repairs move towards completion of the Porte Cochère (Porch). With joinery work completed to the roof structures of the Porch, the race has been on to make the most of the periods of drier weather to get the new roof coverings down, gutters installed, wall head capping’s in place and the final masonry repairs and pointing completed. 

The rooves as installed now are more akin to the original Playfair design with lead coverings laid to fall in accordance with up-to-date technical guidance for lead sheet.  To improve the design, with the aim of improving the longevity of the roof coverings, additional ventilation and additional rainwater goods have been added.  The ventilators installed are in the form of specialist abutment ventilators which allow a clear and continuous air path around the roof to the roof void below.  This is an important addition to the roof which will encourage drying cycles of timber elements, specifically the sarking, in order to reduce the potential impact of under-sheet corrosion to the lead.  As a belts and braces approach, the lead panels have been coated with a chalk emulsion to their reverse side.  The chalk assists with the initial passivation of the reverse side of lead sheet which is not subject to atmospheric conditions.  Additional rainwater goods and oversized outlets have increased the roof’s ability to shed rainwater quickly during increasingly common deluge conditions.  These are supplemented with failsafe overflows which act as a last resort should a pipe or outlet become blocked or overwhelmed. 

 Finally, to help protect high level masonry elements, lead capping has been introduced around the parapets and copes.  When constructed originally, the upper masonry elements were exposed on multiple faces and the parapets provided a route for water ingress into the wall heads.  This resulted in masonry elements going through periods of prolonged wetting leaving them susceptible to erosion, frost damage and limited opportunity to ever fully dry out.  Wall heads are now, insofar as is reasonably practicable, clad in lead to improve their weathering capabilities and help protect the sandstone below. 

 Saving their most skill full work till last and with a degree of nervousness, the masons installed the last two decorative stones – the shimmering stars.  These can only be described as massive!  From the quarry, these two particular stones weighed in at 1.2t each.  Once onsite, each stone block was dressed down by hand to site produced templates.  The process of dressing took around 2 weeks per stone and once completed, each stone was reduced to around 850kg in weight.  These two stones are interesting for a couple of reasons.  Firstly, the Porte Cochère is the only place on the castle where shimmering stars can be found, four in total.  Secondly, we don’t have an original Playfair drawing for these and there were no complete examples left, all four originals being severely eroded.  So many painstaking hours were spent piecing together details from elements elsewhere to get to what we believe is an authentic replica.  This only leaves us to wonder: “why are there only four shimmering stars on the entire Castle, do they hold a deeper meaning and who designed them?”