Lime Render & Rough Cast
Lime render is a surface coating applied to protect the substrate of a building, whether that is made of stone, brick, cob or straw bale. It is softer and more flexible than cement and allows the walls to ‘breathe’. This means moisture evaporates from the walls, preventing water from being trapped inside the building. All pre-twentieth century buildings were built using breathable materials.
Modern materials do not work in the same way and where cement render has been used in older properties this will often crack, letting water into the building which causes damp problems. Once the water is trapped inside the property it cannot get out and these damp conditions can result in the timbers rotting, including beam ends, rafter ends, joist ends and lintels.
At Lime Repair we regularly carry out lime rendering, on all kinds of background and conditions, and we are experienced in handling the structural repairs and replacements necessary to lintels and other timbers where such problems arise.
Conservation is a key part of our work and we are skilled in conserving historic renders, which are generally putty based and are found in many listed buildings. In such cases we can strengthen the historic renders by reaffixing them to the wall.
Lime render can be used in various ways, from a thin coat on flush-pointed stone to a traditional three-coat flat render finish. Typically the lime render is made from hydraulic limes mixed with sand or lime putties with the addition of pozzalan. Also known as ‘stucco’, it is usually painted and protected with limewashes, which are very soft to look at and have an innate, natural beauty that can only be found in natural materials.
As well as lime render, we also specialise in roughcast which is a traditional lime coating, applied directly to flush-pointed masonry or to one or two coats of lime render to give a textured finish. The coat is ‘thrown on’ leaving a coarse texture. It has an increased surface area, which aids evaporation and therefore helps to keep the building dry. Roughcast was used historically on a wide range of properties, from traditional Somerset farm houses to the grandest castles in Scotland.