The benefits of lime plaster

The benefits of lime plaster

Professional Builder visits an Emmerson Critchley new build that’s seeing all of the advantages of an Anglia Lime solution.

“The industry is definitely moving away from sand and cement as an external render – and with good reason,” says Emmerson Critchley. He and the East Anglian building company that bears his name are well versed in the repair and renovation of period properties, but also specialise in bespoke luxury new builds with historical features and character evident throughout, That’s why this property and all other high-end projects will have all the benefits of a product supplied by Anglia Lime Company.

“The UK’s housing stock is constructed on wet earth that will inevitably move, especially in timber frame construction, but the greater elasticity of lime plaster will accommodate far more movement than sand and cement. With freeze/thaw cycles over the course of the seasons, even relatively small cracks, and the subsequent water penetration, can become problematic. Not only that, but bricks are made of clay and need to breathe, and lime will allow a healthy transport of moisture through the material. Using a sand and cement product on a timber frame property effectively means you are suffocating the walls, and that will inevitably cause damp problems.”

The use of lime plaster is typical of the approach adopted by Emmerson, and one that is exemplified in the seven-bedroom property where we caught up with him and his team. “We’re effectively taking a three-pronged approach, with sustainability, a low carbon footprint, and inherent character all working together to ultimately deliver better environments for our clients to live in. On this project no expense has been spared on any of those factors. A glulam timber frame construction with 300mm thick cavity walls filled with Rockwool already provides very high U-values, but add Anglia Lime’s Thermalime as the scratch coat and that takes it well in excess of Building Regulations.”

It is the combination of chalk, St Astier lime binder, fibres and an insulating component that provides that additional level of thermal performance, robustness and a beautiful finish. This bagged, dry ready-mix product can be used indoors as plaster and on the exterior of a building as a render. Zero shrinkage means no cracking, and it is far more durable than sand and cement, or other soft lime plasters that do not contain the fibrous element, a factor which also increases its flexibility.

Mixing animal hair or fibre into lime plaster can also be a challenge for the uninitiated, but Thermalime comes ready mixed, which means it’s simply a question of adding water. Applied by hand, or with a spray gun – if the same atmospherics are in your favour – it can be applied one day and then a top coat added the next. The perfect partner to Anglia Lime’s Thermalime as a skimcoat is the manufacturer’s FineLime, a blend of nonhydraulic lime, chalk and fibres, that’s smooth and easy to apply. FineLime also makes an excellent patch repair product to tidy up old existing lime plasters and can be used internally or externally.

One of the reasons that lime plaster originally fell out of favour was the longer drying times compared to modern gypsum, but for many builders that can actually be an advantage. Emmerson explains: “Experience will tell you what the optimum conditions for applying lime plaster are, but within those parameters it’s actually easier to apply, and a far more forgiving material than sand and cement or gypsum. A longer open time gives you more room to manoeuvre and it’s easier to repair.” On this property traditional wood laths were providing the key for the Thermalime coat but the same manufacturer also supplies alternative substrates, including its Savolit Plus. This wood wool board can be used as a carrier for renders and cladding or as internal lining for timber frame walls.

“This property will be a showcase of what our approach can achieve as a company,” concludes Emmerson, “and we’re very proud of the level of detail. The window reveals are complemented by panels designed and hand-crafted by ourselves, the roof features five different kinds of handmade clay tile, the pentice boards are all lead dressed and a tumbled multi-stock farmhouse brick provides an aged appearance with a modern material. The lime plaster offers a beautiful aesthetic of its own and, importantly, it’s one that will last.”


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