Case 4

Introduction

Type of Building: Residential

This case shows a interior wall affected by lime leaching when lime from mortar joints is brought to the surface as wall dries out.

This is a bad case of lime leaching. The extensive blooming was caused by long term, heavy water intrusion from bad flashing. The wall is the interior wall of a cavity wall construction. This is where two brick walls separated by an air gap serve as one structural wall. Within the air gap is a supply of water soluble salts that has lasted for years. Rainwater has been flowing into the wall gap and carrying salts out for a long time.

Lime can be distinguished from efflorescence because it is associated with mortar joints rather than bricks. Lime staining, like efflorescence is a harmless defect that is considered to be only a temporary disfigurement. This occurs when there is leaching out of calcium compounds which form patches of white carbonates.