Is your brickwork looking tired and in need of a refresh?

Repointing is the practice of restoring the outer face of weathered mortar joints in brick or stone structures. Mortar is designedly softer than the masonry units and over time exposed mortar joints are subjected to gradual erosion due to rain, wind and pollution.  Deterioration of the pointing may allow excessive absorption of water resulting in dampness penetrating through the wall. Trapped water is major cause of salt and frost damage in external brickwork.

It is straightforward to visually assess whether a wall is in need of repointing. Simply inspect the wall and establish whether the mortar is worn and eroded.  If the pointing has crumbled or is missing then it is time to have the brickwork repointed.  Repointing is a slow and laborious process but a good job should ensure the mortar joint repair lasts at least 50 years in most environments.

The mortar can comprise up to 15% of the total surface area; its condition has a huge effect on the quality of a wall and its overall appearance.  There are a number of subtle finishes that can be applied to the mortar to offer the house holder a choice of effects; these include troweling the pointing flush to the brick-surface, at a sloping angle (weather struck) and a finishing with a shallow concave surface.

Great care must be used when removing existing mortar

To prepare for repointing the existing mortar should be raked-out to a depth that is at least two times the height of the joint.  For example a 10mm high joint should be cut to a depth of at least 20mm.  To mitigate the potential for damaging the masonry when raking-out, the process must be undertaken with care.

Existing mortar joints can be cut-back using either chisels, rakes or grinders.

• Soft can be removed using hammer and chisel or a mortar rake.  This is a long slow process and power tools are often utilised to accelerate removal rates.
• Cutting wheels are always used to remove hard pointing and also where joints are over-filled. This is minimizes the risk of damage to the brick edges, which are easily chipped when using chisels.  Cutting wheels are only be used in conjunction with dust extraction equipment.

Before applying new mortar, the brickwork is washed to remove loose particles or dust remnants and the joints are dampened to ensure maximum bond with the new pointing mortar.

Using the correct mortar is crucial for durability

To ensure appropriate levels of strength, permeability and longevity it is necessary that the mortar used for repointing walls is similar in composition to that of the original mortar. A golden rule of repointing is never to allow the strength of the mortar to be greater than that of the bricks.

Buildings constructed before 1920 are unlikely to have mortar with cement content and therefore, to avoid serious problems, should preferably be repointed with a lime mortar rather than a cement mortar.

More modern buildings are more likely to have been built with cement based mortar.

• Lime mortars flex and breathe, they absorb moisture but also allow it to evaporate.
• Cement mortars are rigid, strong and waterproof

When repointing cement mortar joints, there is always a case for making the mortar relatively flexible, by adding lime to the cement mix, in order that it can accommodate natural building movements and allow moisture a degree of permeability. The joint should be cleaned of dust and moistened before the replacement mortar is pushed into the joint. The new mortar is finished by running with a trowel or jointer to deliver a flush, concave or weather-struck surface.

Find the best solutions for porous brickwork

Water Repellent Brick Protection Cream otherwise known as ‘stormseal’ or ‘waterseal’ is a great way to add much needed protection against weather and penetrating damp.

1st Master Wall Ties specialises in protecting brick and masonry from damp that is caused by wind-driven rain. When water comes into contact with porous bricks and masonry some of it is absorbed. The excess moisture can take a long time to evaporate. Damp walls can contribute to structural damage such as cracks, frost damage, wall tie corrosion, algal growth and salt efflorescence.

Much of this damage can be prevented or significantly reduced by the application of a high-quality brick water-repellent treatment that impregnates brick and masonry substrates.

Our masonry protection treatments are based on an advanced silane/siloxane cream formulation, which soaks into the wall, coating capillary pores rather than blocking them. The concentrated treatment provides long term protection from capillary absorption of water yet allows the passage of water-vapour such that trapped moisture can freely evaporate..

Alternatively give us a call on our head office number & book a survey 023 9243 0183