How to repair cracked concrete steps?

Question

I made a repair on some concrete steps. Filling in a cut out corner. Mostly went well. I then used turbo concrete bog to fill a bit of the crack between the old and new concrete so that things would look seamless after painting. About 2 months down the road the constant heat from the sun has caused it to bubble and start flaking off wherever the bog was. I want to grind it back repair it then repaint it. Is there a better product I can use to fill the cracks/join which will be durable enough and also not start swelling with heat exposure?

JacobZ · Answer

Hi @p8128,

Yes, the

https://www.bunnings.com.au/sika-600ml-concrete-grey-sikaflex-pro-polyurethane-sealant_p0083594

would also work just fine.

You'd want to use your grinder to V groove the area for filling, then apply your sealer and smooth it over. Make sure you wear hearing protection, eye protection and a mask to protect yourself while doing.

You can then apply your sealant along the groove, ensuring you get solid connection with the surface on each side of the join.

Once set, you can paint it, adding a little bit of sand to the paint to match the texture of the surrounding area more closely.

Let me know what you think and if you have any further questions, please don't hesitate to ask.

Jacob

p8128 · Answer

Here are some pictures

I also have some of this for some other concrete cracks. Would it be appropriate? https://www.bunnings.com.au/sika-600ml-concrete-grey-sikaflex-pro-polyurethane-sealant_p0083594

JacobZ · Answer

Hi @p8128,

Welcome to the Bunnings Workshop community, it is wonderful to have you with us.

Would you be able to share a photo of the area? That will help confirm the size and shape of the area and how much movement we might expect.

The right product really depends on the specific details, such as the size and depth of the area and whether it butts up against anything.

Without seeing things, I am guessing the issue is because there is movement in that crack and concrete bog is not a flexible product. So, there's a good chance that beneath the paint, the concrete bog has cracked and fractured, which will show up as bubbling or flaking in the paint above.

Again, without seeing things, I'd say a flexible concrete filler such as

https://www.bunnings.com.au/sika-300ml-concrete-grey-sikaflex-11fc-purform_p0628962

, which is paintable, is a better option.

Send through a photo when you can and I can be a bit more specific with product recommendations and the best method of application.

Jacob