Exterior Cleaning for Older Properties: A Careful Approach

Older properties — particularly those pre-dating the 1960s — often have character surfaces that require care and expertise to clean without causing damage. Original stone flags, old concrete, hand-made brickwork, lime mortar pointing, and traditional clay tiles all respond differently to pressure washing and cleaning chemicals. A blanket approach that works on modern surfaces can cause real damage to historic materials.

The key principle for older surfaces is lower pressure and appropriate chemistry. Lime mortar, for example, is softer than modern cement mortar and can be eroded by high pressure. Original stone flags may be thinner than modern slabs and more fragile. Soft washing — low pressure with appropriate biocidal chemistry — is often the preferred approach for sensitive historic surfaces.

Before starting any work on an older property, a thorough assessment is essential. We look at the condition of mortar joints, the hardness of surface materials, whether any surfaces have been previously treated or painted, and whether there are any obvious areas of damage or weakness. This assessment shapes the approach to ensure we clean effectively without causing any harm to the original character of the property.