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How to stop concrete flaking after grind and seal?

Hi,

Thank You for your help/guidance in advance.

We live in Victoria. In year 2023 we got rid of carpet flooring and decided to grind and seal our house foundation flooring. However, the flooring is now flaking around one side of living room due to moisture in the slab.

Any suggestions how we can fix this and if we can reseal it with something waterproof?

Thanks

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EricL

Hello @SunnyB

Welcome to the Bunnings Workshop community. it's sensational to have you join us and thanks for sharing your question about your concrete floor.

It appears that you have water coming through your concrete floor. The water that is coming through is probably flowing from outside your brick or concrete wall. The water is exerting hydrostatic pressure on the seal of your floor and is causing it to lift away. In order to fix this issue. The water from outside must be addressed. This means that the wall outside must be sealed first to prevent water from travelling into your concrete floor.

If your wall is a little bit underground, it must be dug up and a water proofing membrane like Gripset Betta 4L Bitumen Rubber Waterproofing Membrane must be applied. Once the wall has been treated your floor should start to dry out. When it is completely dry that is the time you can seal it back up again. However, if you find that it is too difficult to gain access to your outside wall, I suggest engaging the services of a trade's person to do the job for you.

If you need further assistance, please let us know.

Eric

Jason

Let me also extend a very warm welcome to the community @SunnyB.

Sorry to read of the issue with your floors. I trust you found Eric's reply helpful. Let me tag experienced renovator @Nailbag for a second opinion for you.

Jason

Nailbag

Hi @SunnyB

with those very apparent dark regions near the wall, I would have to agree with @EricL that the moisture is likely to be originating from internally within or externally from the wall. Take special note of his comments regarding: external ground level being higher than the internal. It might require a combination of external waterproofing and drainage system.

Nailbag

SunnyB

Hi @EricL @Nailbag @Jason

thank you for your time and response.

unfortunately I won’t be able to do much to the outdoor area because we have a concrete pathway along the house that pretty much is at the same level with our internal floor.

is there anything that I can spray in between to keep the moisture out or keep the floor dry?

EricL

Hello @SunnyB

Thank you for sharing that extra picture of your house. If the water is travelling under the walkway slab, spraying the outside surface will not be effective. Spraying inside is also not an option as the spray will simply lift off the moisture filled floor. In order to get access to your outside wall, the concrete walkway will have to be cut and part of it broken apart to allow you to dig to the floor level of the house. Should the dark patch on your concrete floor travel the entire length of the wall, it will be necessary to dig along that wall so that entire section can be sealed properly.

If you wish to cover the gap between the house and the walkway, I suggest using Moroday 15mm x 5m White Gap Filler Rod and pushed in at least 10mm deep. I then recommend covering the gap with Sika 310ml Grey Concrete Sikaflex Pro+ Polyurethane Sealant.

In this particular situation, I suggest engaging the services of a concrete sealing specialist in your area. They will have the knowledge and experience on how to deal with the leak inside your floor.

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you need further assistance, please let us know.

Eric

Nailbag

Morning @SunnyB

What @EricL has suggested is exactly what I would be too. The only other addition would be to consider some venting on the 2nd brick course. It could be something simple like drilling out a few of the vertical mortar courses or replace a 2-3 bricks a couple of metres apart with grills.

Nailbag

Dave-1

Morning @SunnyB

I had water entering under the house from my side path that was solid concrete, I seriously did not think water could travel under the path (squeeze down the hair thin line of concrete to brick) and then make its way through the brick work and have enough to run across the ground. How wrong was i lol I actually removed my concrete side path to fix another problem and then when I redid the pathway I gave it the ability to free drain the way I wanted it to. No more water under the house 🙂

The reason for the story is to show that sometimes the harder choice (Cut the outside pathway, seal the edge and drain the underside) may be an overall easier fix long term to stop the moisture rise on your polished concreet floor. Trying to seal the area without getting down to the subsurface may not work the best.

Dave

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