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How to stop efflorescence on brick wall?

Good Morning,

External garage wall weep holes partially covered by side concrete works & when it rains water flowing towards the brick wall this causing efflorescence. Can I completely seal the partially weep holes and create new one bit above? if so how to create them?

what to prevent water flowing toward the wall?

Water flowing towards brick wall.jpg

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MitchellMc

Hi @kiranraob4u,

Weep holes are located at the bottom of a wall for drainage of the cavity. Their purpose is to allow moisture that accumulates behind the brickwork to escape, helping to prevent water from getting trapped inside the wall. Moving weep holes higher up the wall is not advisable, as doing so could lead to water being retained in the lower section of the wall. This would likely result in serious moisture issues, including dampness and potential damage to the structural integrity of the wall.

Another important consideration is the level of the concrete work around your garage wall. If the concrete has been poured above the damp-proof course (DPC) line of your wall, water can start creeping into the mortar joints and wicking its way up through the brickwork. This process, known as rising damp, can cause efflorescence, as you’ve already noticed, as well as more severe long-term damage such as mould growth, brick deterioration, and even structural weakening.

Ideally, the concrete should not have been raised above the damp-proof course or covered the weep holes. The DPC is a critical layer that prevents moisture from migrating upwards through capillary action. Covering it can negate its effectiveness, leading to moisture-related problems inside the garage as well.

As for how to prevent water from flowing towards the wall, the key solution is improving drainage around the concrete area. I’d suggest looking at ways to redirect water away from the garage wall, perhaps by introducing proper sloping or grading of the concrete slab, installing surface drains, or even considering a trench drain system to catch the runoff before it reaches the wall.

Because this situation involves multiple issues—concrete levels, weep holes, and drainage—I’d highly recommend enlisting the help of a professional who can assess the site and work out a comprehensive solution. They can check whether the concrete is indeed above the DPC line and suggest ways to adjust the grading or install additional drainage to keep water from collecting near the base of the wall.

One possible solution could be to cut the concrete back 100mm from the wall and install a sunken drainage grate along the wall below the weeper holes and DPC.

In the meantime, it’s essential not to seal the existing weep holes or create new ones higher up, as this would only mask the symptoms rather than address the underlying cause. Proper drainage and ensuring the DPC is above ground level are the real fixes to avoid moisture damage in the future.

Feel free to reach out if you have any further questions or need more advice.

Mitchell

kiranraob4u

Thanks Mitchell,

Until I find a professional help or a concreter to install drainage grate any temporary solutions like sand bags or any other thing?

Regards
Kiran

Dave-1

Good Evening @kiranraob4u

I would suggest against sandbags or covering them up for now. Id probarly sweep the area and not hose for the time being.

Take as look at my project where I had to get my concrete driveway cut to install drainage. You would have the same cut down the side of the driveway. It depends if they have attached the slab to the house or not as to how easy it may be to remove (bolts put into the brickwork for the concrete to attach to plus reo) I was lucky and there was no attach points)

Fixing water ingress issues in garage in particular step 3

Just think of where you could run a drain away from the house and what the grounds slope is like.

Not something you have to react to imediantly but something that does need looking into to solve I would suggest.

I had my carpenter mate cut the concrete one afternoon for me, paid him for the work as I was supper stressed to attempt to do it myself 🙂

Money well spent and even tho he "claimed" he did the size perfectly for the pavers I do think it was good fortune more then intention 🙂

Dave

kiranraob4u

Good Morning Dave,

Thanks for your input. Not to block the weep holes with sand bags place them slightly away from the wall so that water will not reach the wall/weep holes.

From the photos it looks like they have not bolted to the bricks I am not sure if they did while pouring the concrete.

Expansion foam not installed between brick wall and concrete do you suggest waterproof caulking to the rest of the area where weep holes are not submerged by concrete.

Weep holes are partially submerged at external garage wall as garage has step down rest of the house is fine.

Regards

Kiran

MitchellMc

As a temporary solution, @kiranraob4u, I think sandbags would be fine. As you mentioned, have them set out slightly from the wall so they block water flow towards it but don't inhibit drainage from the vents. There's likely very little water that will be draining from them; it's more about stopping water from running into them at this point.

Mitchell

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