Masonry restoration

Repointing and replacing bricks

Brick masonry consists of bricks and mortar. Natural processes as well as wear and tear impact the wall, giving it patina but also reduced strength. Bricks come in different dimensions and with different properties, varying from air-dried clay to hard-burnt dense and non-absorbing bricks.

Excessively strong mortars can cause damage to bricks and joints.

Stress due to weather and natural decay will clearly make it necessary to repoint a brick masonry wall (e.g. change the pointing mortar). The reason for the decay is a combination of products, original application method, and repair materials. Joints based on lime mortar will decay naturally under the influence of water, become sandy and lose strength. This will also happen when excessively strong repair (cement-based) mortars have been used. Water gets trapped behind the strong, low-capillary layer and pulls the joints out. In the worst cases, these high strength joints, and also often in combination with high strength renders, will damage not only the joints but also the bricks. This can lead to the collapse of the whole or parts of the façade.

Replace bricks and repoint joints

Brick wall

A rule of thumb states that bricks with more than 10% damage should be replaced. Bricks with a damaged, burnt outer layer should also be considered for replacement. Please take into consideration the building's historic importance as well as the new use of the building before considering replacing bricks. In some cases, a damaged wall or brick should only be conserved and not repaired. If replacing a brick, the joints around it should be carefully removed, and a new brick of the same size and suction should be used together with a repointing mortar of equal or less strength than the original. In the case of repointing, old joints should be scratched out to a depth equal to twice the width of the joints or to a solid background. The joints should then be cleaned and repointed with a mortar of equal strength as the original in a minimum of 2 layers, and using the same technique and design as the original.