25/07/2026
Lime render and cement render are not interchangeable.
Members of our team recently attended practical lime rendering and harling training with the Scottish Lime Centre Trust, developing their knowledge of traditional materials, preparation, application, finishing and curing.
Many older Scottish properties were built with solid stone or brick walls bedded in lime mortar. Unlike modern cavity-wall construction, these walls manage moisture by allowing it to move through the masonry and evaporate through permeable mortar and external finishes. Properly specified lime render is generally more vapour-permeable, flexible and lower in strength than dense cement render. It is designed to weather sacrificially before the stone or brick behind it.
Dense Portland cement render is harder, more rigid and less permeable. When applied to traditional lime-built walls, fine cracks can allow rainwater behind the render while restricting the wall’s ability to dry. Over time, retained moisture may contribute to dampness, salt crystallisation, frost damage and deterioration or spalling of the masonry beneath.
This does not mean that cement render is unsuitable for every building. It may be appropriate for modern blockwork or cavity-wall construction designed for a cementitious render system. The correct material should be selected only after assessing:
the original wall construction and mortar;
the strength and condition of the masonry;
exposure to wind-driven rain;
existing moisture problems;
the required finish and curing conditions.
The training also covered traditional Scottish lime harling, where lime and aggregate are cast onto the prepared background to create a weather-protective finish. Correct preparation and controlled curing are critical; fresh lime work must be protected from rapid drying, heavy rain and frost.
At A.D.I Builders Ltd, we continue investing in practical training so that traditional walls are repaired using materials compatible with the way the building was originally constructed.
For enquiries regarding lime rendering, traditional harling, lime pointing or masonry repairs, email:
[email protected]
A.D.I Builders Ltd
Aberdeen Trusted Trader | CHAS SSIP | Constructionline Gold