Masonry restoration

Stabilisation with injection

Different types of injection methods are used nowadays to stabilise constructions. The method is used in brick masonry, natural stone masonry and bigger constructions. Both underground and overground.

Binders disappearing from the construction

Water has the ability to penetrate into any construction through cracks, fissures and especially through capillary suction. Capillary suction takes place in the mortar joints and in brick masonry. This can rise up to 150 cm above the water level. In normal environments, the abundance of water will reinforce the lime mortar, but in the case of excess water, the lime binder will dissolve and lose its binding effect, leaving only the aggregates as a skeleton. Both salt efflorescence and washout of lime can occur. As a result, lime will be washed out through cracks in the wall over time, especially if it is a high-lime mortar with low/no hydraulicity. Piles of sedimented carbonates on the outside of the wall is a good indication of such a process. The washout results in destabilised constructions. Sometimes, this washout is not seen until renders, paints and foundations have been removed or examined by thermographic methods.

Stabilising the construction from the inside

Rising damp

Injection with specially designed materials is a good method for stabilising and replacing the missing lime in the bedding. Often tearing down and rebuilding a construction isn't possible - especially if we are dealing with foundations. Carefully planned injection schemes can then be used. The hollow structure is identified using thermal imaging and flowing water, and a carefully planned array of holes are made in the construction. The holes are then filled manually or using a pump with an injection mortar designed for the project. Depending on the construction, cement- or lime-based mortars with a high flow rate and small particle size are used. The injection mortar is carefully designed to ensure good hardening processes since the contribution of CO2 to the carbonation process is almost non-existent inside the construction. After filling the holes, a new thermographic image is taken to ensure that all big cavities are filled. This method can also be used for damp proofing and inhibiting rising damp.