Our external lime renders predominantly incorporate a hydraulic lime, with the exception to this being when a softer render consisting of a lime putty is used on a Cob/Clom building.
External renders can be finished to achieve a multitude of effects, which can fulfill the requirements of both design and what is best for the building. The latter concept should take into consideration the buildings environment, such as its orientation, exposure, and altitude. Meaning a roughcast finish would be required to protect against heavy weathering, whereas a standard stucco finish will suffice on most buildings.
Our external renders take the form of a standard three coat work when applied to most stone based backgrounds, starting with the important pointing and dubbing-out coat, followed by two more coats. This approach will achieve the flat, stucco effect that is most popular. The two base coats will contain a form of hair to assist both the compressive and flexural strength of the plaster.
All lime renders must be finished in a breathable paint such as a limewash or silicate paint, which adds to the protection of the building as well as its character.
Its crucial that the type of render being applied and its strength is appropriate to the location and exposure of the building. For instance, an 'exposed stone' building close to the sea is likely to suffer from heavy wind driven rain, and a pointed surface offers the least amount of protection, which is why roughcast renders are so common in exposed parts of the country such as West and North Wales, Scotland etc.
Internal lime plasters incorporate a lime putty with an appropriate aggregate as well as a reinforcing fibre such as horse hair. An exception to this rule is lime hemp plaster, whereby the aggregate is both the aggregate and reinforcing fibre. Lime hemp plaster is an excellent alternative to standard lime putty and aggregate. Hemp itself is essentially a straw-like material that is cut up to various sizes and therefore suitable for a range of applications, including a finishing plaster. The nature of the material makes it very strong as its fibres interlock when applied, making it a useful material for those rounded corners of window reveals, as well as for plastering onto reed or lath
Internal plasters can be applied to a variety of internal substrates, whether that be onto the structural stone or brick walls, or onto partitioning walls consisting of laths, woodfibre, woodwool, or reed.
The breathability of lime plasters means that they need to be protected with a paint that is also breathable, such as a limewash. It is not advisable that such a surface be covered with modern plastic paint, as they can trap moisture and will simply flake off.