How to fill hole in laundry floor after removing trough?

Question

Hi everyone,

I really need some advice on this one. When we bought our house, the previous owners had renovated and installed a new laundry sink. However the 'new' sink is smaller than the original sink and there is a large hole in the laundry floor.

We don't have the money to do a full reno on the laundry at this stage. I thought of pulling out the basin cupboard floor and trying to fill the hole with cement. But the cupboard flooring is secured with rivets not screws. Is filling the hole with cement a feasible choice? If so, how would I do it?

I just want to fill the hole. I don't need it to have tiles and look pretty. I just don't want this gaping hole in the floor anymore.

I'd love some suggestions because I have no idea how to fix this.

Thanks in advance,

Sonja

MitchellMc · Answer

Hi @sonja09,

Great question and nice work checking underneath first, that definitely helps.

Yes, you’ve got the right idea. If the hole drops away further under the cabinet, you’ll want to block that back section off so the self-levelling compound doesn’t just disappear into the void.

You can do this by pushing something into place at the back of the hole to act as a barrier. A piece of timber, rigid foam, or even tightly packed cardboard will work. The key is that it’s firm enough to hold the wet mix in place while it sets. Try to position it just beyond where you want the fill to stop (basically under the cabinet edge), so you’re only filling the visible and accessible section.

Once your barrier is in place and the base is built up a bit, you can go ahead and pour the levelling compound. Just take it slow and guide it into place with a trowel.

You’re definitely on the right track, so feel free to ask if anything comes up while you’re doing it

Mitchell

sonja09 · Answer

@MitchellMc thank you so much for the suggestion. That's really helpful. I'll give that a try.

I managed to look under the cabinet and hole deepens a more at the back. Do I insert the foam/cardboard/wood into the hole toward the back (under the cabinet) to contain the cement and prevent it from running off into the back area of the hole?

Thanks for your suggestions and your help. 😊

Sonja

MitchellMc · Answer

Welcome to the Bunnings Workshop community @sonja09. It's a pleasure to have you join us and many thanks for your question on filling a floor.

Using a self-levelling cement compound is a solid, practical option here. It’s designed for exactly this kind of situation of filling low spots or holes in concrete floors with minimal effort.

Here’s how you can approach it:

* Clean the area first: Remove any loose debris, dust, or old material from the hole so the cement bonds properly. A quick vacuum helps a lot.
* Check the edges: If there are gaps where the mix could run off (especially under the cabinet), you might want to block them temporarily with a bit of timber, foam, or even cardboard.
* Mix the self-levelling compound: Follow the bag instructions closely, as getting the water ratio right is important so it flows properly.
* Pour it in: Start at the front and let it spread. Don’t overfill all at once.
* Use a small trowel: They are perfect for guiding the mix. Push it slightly back under the cabinet.
* Smooth it off: Lightly trowel the surface so it sits level with the surrounding floor.
* Let it cure: Most products set fairly quickly, but give it the recommended time before putting weight on it.

A couple of practical notes:

* You don’t need to remove the cupboard floor if you can access the hole well enough from the front.
* Don’t go too far under the cabinet. Just under the visible edge. If you apply too much, you might find it tries to seep out the sides of the cabinet.

Please let me know if you have any questions.

Mitchell