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We have an old shed that we would like to tidy up for a bit of a hobby space. There is a significant crack in the concrete, approximately 20m wide.
Is it fixable? We will probably cover the surface of the concrete, so it doesn’t matter how the patch ends up looking.
Welcome to the Bunnings Workshop community @bekamo36. It's wonderful to have you join us, and many thanks for your question about repairing a crack.
That kind of crack isn't really fixable in the sense of preventing it from getting worse over time, especially in an old slab where movement may continue, but it’s definitely fillable, which will neaten things up and make the surface safer and more usable. Since you're planning to cover the concrete anyway, filling the crack will help provide a more even base.
I'd recommend starting by cleaning out the crack thoroughly, then pushing some foam filler rod (also called backer rod) down into the gap, about 5cm below the surface. This acts as a backing to support the repair material and stops you from using more filler than you need. From there, you can pour or trowel in a concrete repair mortar or crack filler over the top. Just make sure to use a flexible repair compound if there’s any chance the crack might continue to move.
It won’t stop the crack from eventually widening again, but it’ll make the slab much tidier and safer in the meantime—perfect for a hobby space.
Please let me know if you have any questions.
Mitchell
