Heritage properties can be some of the trickiest to work with. Often, there are lots of issues to contend with when it comes to older properties. Quite a few heritage properties have been rendered over with sand and cement, while others are solid wall buildings with very little insulating capabilities.
Today we’re going to be discussing the ideal solution for insulating a heritage property externally – from the actual insulation material itself to the decorative finish.
Heritage properties need breathable materials
Because heritage properties are typically made of porous materials such as sandstone and limestone, they rely on the breathability of these materials to allow moisture to escape from their structures.
Sticking a vapour impermeable sheet of insulation or a cement render onto the building’s walls would only serve to hinder the building’s own functionality. When it comes to external wall insulation, the insulating material needs to be suited to the building fabric – it’s imperative that the materials work in conjunction with each other.
Breathable insulating materials are able to effectively control the moisture that passes through the walls. Therefore, care must be taken when selecting the external wall insulation materials; Wood Fibre insulation is always a great choice for heritage properties as it is completely breathable.
Heritage properties are very often timber frame. Wood Fibre insulation is made from waste timber shavings and is therefore entirely suited to a timber frame property; the materials work together harmoniously to allow the building to breathe.
Thin Coat Renders on Heritage Properties
Thin coat renders are a great way to achieve a decorative, crack-resistant external facade on your home. However, with Heritage properties it’s essential that you choose the right one; although most thin coat renders are polymer modified, some do not offer breathability.
At EWI Store, we always recommend going for a Silicone render as a topcoat to your external wall insulation. This is because it is very breathable and will not hinder the breathability of the system.
If you are simply looking to render the property without insulating, then lime-based renders are definitely the way to go. Lime renders are very traditional and are therefore the ideal material for use with heritage properties.
Lime is an incredibly porous, long-lasting material – buildings made of limestone or sandstone will have typically been built using a lime mortar, so a lime render on top will work harmoniously with the rest of the building fabric.