How to build a shed base for outdoor laundry?

Question

Hello Everyone,

I’m working on my shed floor (about 1400 x 1900 mm) which currently has an existing brick base. The bricks are structurally solid, but the surface is uneven.

This shed will be used as an outdoor laundry (washing machine + dryer), and while water doesn’t usually get inside, it’s not a fully sealed indoor space either.

I’m deciding between two options:

* Using a self-levelling compound over the bricks and then installing tiles.
* Pouring a full concrete slab over the existing base

I’m trying to understand:

* Is the brick base + self-leveller strong and durable enough long-term for this use?
* Or is it better to go with a proper concrete slab for peace of mind?
* Any issues with moisture, cracking, or tile adhesion I should consider?

Would really appreciate advice from anyone who’s done something similar 🙏

Thanks in advance!

Vardhan07 · Answer

Thanks @EricL for the suggestion, I agree concrete slab will give long term support.

EricL · Answer

Hello @Vardhan07

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your shed base.

Using a self-levelling compound provides a level base but does not give any structural support. If the bricks move the surface cover will crack and if the movement is significant or continuous the surface cover will break.

Is the brick base + self-leveller strong and durable enough long-term for this use? There is a higher possibility of movement should water enter under the brick base. Whereas a solid concrete slab will retain its level and will take a large amount of water to affect its level. It may take more work but for long term stability I suggest going with a concrete slab.

If you wish to protect the items and appliances inside the shed, I suggest installing builder's plastic to prevent moisture from coming through the slab. My best advice is to make sure that the slab is fully cured before you tile over it.

Here is a handy step-by-step guide: How to pour a concrete slab by @tom_builds

If you need further assistance, please let us know.

Eric