Bathroom Floor Leveling: Concrete Slab Repair and Shower Crack Prevention Before Cement Bedding.
- Jax Tiling
- 7 days ago
- 2 min read
prepping-the-bathroom-floor-before-cement-bedding-repairing-a-crack-and-lowering-a-high-spot-at-the
We specialize in bathroom tiling, based in Parramatta, and we proudly serve a wide area across Sydney, including Western Sydney, Inner West, Northern Sydney, as well as suburbs like Castle Hill, Kellyville, Glenwood, Ryde, Hunters Hill, Baulkham Hills, Blacktown, Penrith, Ermington, Rydalmere, Oatlands and other surrounding suburbs.
Bathroom floor leveling, concrete slab repair and shower crack prevention.
In this blog post, I take you step by step through the process of preparing a bathroom floor before we apply cement bedding. In this particular bathroom, we faced a significant challenge: a high spot in the concrete slab. The floor was sloping toward the door, and if we applied the cement bedding without adjustment, it would create a very high step at the entrance. This could be not only unsightly, but also a serious trip hazard, particularly for elderly individuals or anyone who struggles with lifting their feet.
In the video, I show how we addressed this problem by lowering that high spot in the concrete slab. First, we pinpointed exactly where the slope was causing the problem. Then, we used a jackhammer to carefully remove the excess concrete from that high point. The slab was thick enough to withstand this, so we were able to take it down without compromising the structural integrity.
After we lowered the high spot, we turned our attention to a crack that ran between the main bathroom zone and the shower zone. This crack was a potential weak point; if we didn’t address it, it could allow movement that would transfer up through the tiles. I applied a flexible sealant directly over the crack—this acts like a bond breaker, allowing the floor to move slightly without the crack transferring upwards. On top of this, I laid a plastic sheet to create a slip plane, ensuring that the movement wouldn’t stress the tiles. Then, I added a wire mesh on top for reinforcement.
Once that was all set, before we laid the cement bedding, we waterproofed the entire bathroom. In the waterproofing phase, I made sure to apply a bandage—a flexible membrane patch—right over that crack. This bandage acts like a safety net: if the crack ever tries to move or reopen, the bandage stretches, keeping the waterproofing intact and preventing any leaks from ever reaching the substrate below. This entire process ensures that even if small movements happen, the crack won’t transfer up through the tile, giving us a durable and long-lasting finish.
I hope this detailed walkthrough helps you understand how crucial these preparatory steps are. By taking the time to correct the slope and reinforce the crack, we avoid future issues and ensure that the waterproofing stays intact for years to come.
Disclaimer: The methods shown in this video are based on my personal experience. Every project is unique, and I strongly recommend seeking professional advice for your specific situation. I am not liable for any damage or issues that arise from DIY work. Always ensure you do your research or consult a qualified professional before starting.
Disclaimer: The methods and steps I describe are how I, as a licensed professional, carry out this work. However, every project is unique. I recommend evaluating your specific circumstances and seeking additional professional advice if needed
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