Kelleher and Associates carry out many pre-purchase surveys of older period, often protected, structures. Unfortunately, very many older brick-built properties have pointing that is in a poor state of repair or has been incorrectly pointed.
Frequently, aggressive cleaning causes permanent damage to otherwise only lightly soiled brickwork that can be brought back to life by minimal intervention.
The photographs of the red brickwork are fairly indicative of the problems we encounter during property surveys.
A fairly high percentage of the brickwork has suffered significant ‘freeze-thaw’ damage as a result of trapped moisture within the brickwork freezing and causing some of the brickwork facings to delaminate. The core of the brick is now exposed allowing moisture to be transferred from the exterior to the interior of the property.
In the case of the examples shown, the use of hard cementitious pointing is the primary cause. Dampness internally was a problem. This pointing needs to be completely removed, an expensive and laborious process, that can only be carried out by a specialist contractor. Lime-based mortar should be used as a replacement pointing material. Badly damaged bricks should be replaced. Salvage yards usually stock matching machine made bricks.
In the case of the yellow stock bricks the original pointing had deteriorated to a very friable condition to the stage that the structural integrity of the external walls was compromised.
Re-pointing will be more straightforward in that modern pointing does not have to be removed. Mortar analysis is recommended to ensure replacement mortars are the right mix.
Never sand blast old brick. Gentle cleaning is sufficient to remove surface dirt.
For any structural pre-purchase survey needs – contact us.