When developer Marco Williams of the Bromley based North Star 2000 Group added The Rookery mansion house to his property portfolio, it was quite a departure from his normal line of work. It was a move which lead him and his decorating contractor, Richard Payne, to become better acquainted with traditional lime render and the benefits of the Sandtex Trade mineral paint system, Integrasil.

North Star 2000 is best known for building exclusive boutique apartments in South East London, but that didn’t deter Mr Williams from purchasing The Rookery, a rambling, dilapidated eighteenth century mansion house in the ancient Kent village of Downe.

Mr Williams said: “I’d known the grand old villa since I was a child and when it came onto the market I bought it with a view to making it my family home. However, I soon realised it would make far more sense to convert it into six luxurious town houses that I could sell individually.”

In order to renovate the exterior masonry of the building, which dates back to 1724, Mr Williams insisted on using traditional lime render. He said: “At North Star we aim to use materials which are in sympathy with their surroundings and in keeping with the age and heritage of a building. Although it meant bringing in specialist contractors and incurring considerable expense, lime render also offered a high level of flexibility and a much reduced risk of cracking over time.”

Asked to specify a suitable decorative coating for the masonry, decorating contractor Richard Payne turned to Sandtex Trade and the Crown Paints specification team for advice. The Integrasil mineral paint system was recommended as it is one of very few coatings available in the UK considered suitable for application over lime render. In addition to offering long term decorative benefits, Integrasil bonds with the substrate and provides long lasting weather protection whilst allowing water vapour molecules to escape, effectively allowing the building to breathe.

A full specification was provided but it was several months before the painters could start work. Mr Williams explained: “The lime render took a very long time to cure as we were working over the winter. In fact we had to remove some of it and start again on one part of the building because the frost got to it, which made it a long drawn out job.”

When the render eventually dried, Mr Payne’s men moved in with cherry pickers to start the three-coat Integrasil application. Mr Payne said: “All the newly fitted windows were still protected with the manufacturer’s shrink-wrap, which was very convenient for us. Mineral paint is highly alkaline, which gives it great appearance retention and resistance to algae and mould growth, but it does means that surrounding areas need to be well masked and that you should also wear suitable protective gear.”

He continued: “First we applied a dilution of Integrasil Primer. This was followed by a first coat of Integrasil mineral paint, which we mixed 80:20 with the Primer. To be honest we were initially surprised and even a little concerned at the extent to which the paint was being absorbed by the render, but we were assured that this is exactly what should happen. The paint is formulated so that it penetrates deep into the substrate and creates a permanent chemical bond, rather than creating a continuous film on the surface like conventional masonry paint.”

Mr Payne said: “When we started to apply the second top coat, which was the mineral paint mixed with 10% Primer, we finally got the level of opacity and coverage we had been waiting for. The paint dried to a bright opaque matt finish and it effectively filled in all the fine hairline cracks that had appeared as the plaster dried out.”

Mr Williams confirmed that the Sandtex Trade Integrasil mineral paint system had proved to be the ideal coating for use with lime render and that he was extremely pleased with the finished results. He said: “Working with traditional materials has been quite an experience for us all, but Mr Payne’s team rose to the challenge and they’ve done an excellent job for me, as always.

“The project is now complete and I have six stunning new luxury properties to sell. The interiors of The Rookery have obviously changed beyond recognition during the conversion, as you would expect. But with a little help from Sandtex Trade we’ve restored the exteriors of this impressive property to their former glory.”