How to install new bathtub into existing bathtub location?

JohnPaul1972

Hi there, I need some advice on what best to do here. The existing bathtub was approximately 100mm below the existing black floor tiles. Do I fill in the floor with new cement/concrete to the height of existing adhesive of existing floor tiles? Do I install reinforcement bars too?

MitchellMc

Welcome to the Bunnings Workshop community @JohnPaul1972. It's terrific to have you join us and many thanks for your question on installing a bath.

Please note that plumbing work needs to be completed by a licensed professional for safety and compliance.

You can fill that recessed area, but it’s important to do it properly rather than just pouring concrete straight in. Start by thoroughly cleaning out all loose debris, old adhesive, and any contaminated material, and treat the stained areas for mould since it looks like there’s been long-term moisture exposure. Once the base is solid, apply a bonding agent to help the new concrete adhere to the existing slab, then fill the recess with a concrete or sand/cement mix to bring it up close to the finished floor height, allowing for tile and adhesive if you’re retiling.

In most cases, you don’t need reinforcement bars for a small area like this, but using a light-gauge reo mesh can help reduce cracking. After it cures, make sure the surface is level and apply a proper waterproofing membrane if required before installing the new bathtub.

Please let me know if you have any questions.

Mitchell