Lime can be used in place of cement render where flexibility and breathability is called for most notably in energy efficient housing and passive home construction where moisture permeation can be an issue for other materials. Lime tends to be more labour intensive to apply than regular sand and cement and so it is mostly used for conservation work such as the work that the McErlean Plastering team carried out on the national trust property at Lissan House in our projects section.
Lime does have some advantages over cement renders:
It is more flexible
Problems are less likely to occur with
moisture getting trapped within the wall. This is a problem when cement renders are applied to old walls.
Lime also tends to look very appealing, though it does require frequent coats of limewash.
Building limes are available in different formats, from traditional lime putties to bagged hydraulic limes, which behave rather like weak cement. They need to be mixed on site with sand, and are hand trowelled in the traditional way and require specific temperature conditions for application. Suppliers such as K Rend now offer lime-based polymer renders which offer the benefits of both worlds.
McErlean Plastering continues to develop its reputation as one of the leading lime render specialists in the UK and Ireland. Recently we have expanded our range of lime products to include Keim lime and K Lime.
What factors affect render choice?
There are a number of factors that will affect your options when it comes to choosing your exterior finish. At McErlean Plastering we believe the better informed you are about the factors required for material choice then the better decisions that you can make but ultimately it comes down to personal preference and how your choice will work in the setting that your construction project is in.
Some of the most important factors include:
What is already in place? Prevalent in renovations or restorations - This is the material that will be under the finish of your choice and ultimately the layer that the top coats will bond to. This is particularly important when using a render as it will have to adhere to this surface and move with it
Age of the property – How old the property is and how it was constructed will have a bearing on the amount of preparation, repair and ongoing maintenance that you will likely have to do to the exterior of your home. A Sand and cement render to a stone-based structure would cause issues to that property regarding moisture retention if other steps are not taken in the building process.
The finished look – Unless you are in a listed property this is the one thing that should carry the most weight. You must ensure that your property is finished in a way that you find attractive and is in keeping with its environment.