Should I Waterproof My Brickwork?

Many people falsely believe that due to modern building methods, including the use of impermeable materials and cavity walls, that they do not need to protect the external brickwork and masonry, but this assumption can prove costly in the long run and penetrating water can cause damp, mold, timber damage and a loss of structural integrity. This blog post will explain why waterproofing brickwork is important, what you should use to achieve this, and how you should apply it.

Penetrating damp can cause major structural issues if left unchecked. External brick walls (typically garages) are exposed to driving rain, and this is absorbed into the brickwork and travels laterally to the inner walls of the garage where it causes damp patches. This penetrating water washes ‘salts’ out of the brickwork, creating crunchy deposits on the internal walls, damaging the paint and plaster. These damp patches formed on the internal walls lose heat faster than non-damp sections of wall, resulting in increased moisture in the garage, resulting in condensation which if left unchecked can cause dangerous black mold.

Another reason to waterproof your external brick wall is to prevent further structural damage. Water expands upon freezing, which increases the amount and size of cracks in the external wall. This results in more water penetrating, which in turn freezes and compounds the problem. These large cracks can then get moss and mold growing in them, damaging brickwork and timber, making the wall unstable. It is therefore imperative that you waterproof the external brickwork of your garage to save you a lot of time and money further down the line.

Firstly, before you do any waterproofing, you will need to resolve any structural issues with the external brickwork, otherwise you will be wasting your time as water will still be able to penetrate. Any damaged bricks will need to be replaced, and damaged mortar will need to be pointed.

There are many different brick waterproofers on the market, but you need to check that the one you have chosen will still allow the brickwork to breathe, and that it is absorbed deeply into the brickwork. It is important that it allows the brickwork to breathe, otherwise moisture currently in the wall will be trapped and result in damp and mold. Water repellent treatments such as siloxanes, silanes, silicates, etc. are good as they penetrate deeply and allow the brickwork to breathe. They are not a permanent solution and need to be reapplied. Please check the directions on your chosen water repellent and remember to reapply as instructions in the directions.

Once you have applied the external waterproofer to the brickwork, you can begin to deal with any internal damp patches. You should use a salt neutraliser or anti-mold cleaner if the plaster is still structurally sound. If the plaster is unsound, you will need to remove the damaged plaster, use the anti-mold treatment, replaster, and then apply a waterproof render.

If you follow the recommendations above, your garage’s external walls will be protected from damp, mold, frost damaged and pollutants.