Hybrid floor over tile or remove tile and re-tile?

[AntonT]

Hi. 

I have a mid-80's house on concrete stumps and the bathrooms and laundry have tile over concrete screed over floorboards.

I would like to renovate the bathrooms and for the floors, either:

1. Install a 5mm+ hybrid floor over the existing tile. I believe the tiles are already on a waterproofed floor, so the only issue I see would be the floor height which I can manage with trim at the doorway. And perhaps needing to level and waterproof an area after the vanity is removed. Would there be other issues with this? 

2. Remove the tiles and the screed back to floorboards, waterproof and tile again from scratch. This seems like it will be the more expensive option but perhaps better for drainage. 

I feel that I am missing some pros and cons to make an educated call.

Does anyone have any advice or thoughts? 

[Jason]

Welcome to the Bunnings Workshop community @AntonT. We're pleased to have you join us and look forward to seeing how you can transform your home.

Let me tag some helpful members to share their thoughts on how they would update your flooring: @MitchellMc, @TedBear, @CSParnell 

Feel free to post anytime you need a hand with your projects or have something to share with the community. 

Jason

[AntonT]

Thank you Jason. I appreciate the help. 

[MitchellMc]

Hi @AntonT,

You can install Hybrid waterproof flooring over your existing tiles, which will likely be the most straightforward solution. Hopefully, that vanity has been placed on top of the tiles, and you don't need to waterproof that area. You can't patch waterproofing; it needs to be one consistent layer over the whole floor.

If you were to remove the tiles and screed back to the floorboards, you'd need to install ceramic tile underlay and waterproof. Here's a helpful step-by-step guide: How to waterproof a bathroom floor.

Let me mention our resident waterproofing expert @Vis-á-vis to get their thoughts.

Please let me know if you have any questions.

Mitchell

[AntonT]

Thank you Mitchell. I read the hybrid flooring is waterproof. I assume that you'd still need to have a waterproof layer under it in a bathroom. 

Is waterproofing required in a laundry or separate toilet? 

[MitchellMc]

@AntonT,

Hybrid flooring is waterproof itself but doesn't remove the regulation of needing to have a waterproof membrane in a bathroom.

Typically a laundry is considered a wet area and requires floor drainage and waterproofing. Given the high chance of water leaks, not waterproofing would be a huge risk to take. It could also negatively affect your ability to sell the property, and inspections generally look for adequate waterproofing of wet areas.

For a WC which houses only a toilet, you should read through AS3740. It's my understanding that there is currently no provision to waterproof the toilet area if it is not inside a bathroom. Hopefully, @Vis-á-vis can clarify that for us. 

Mitchell

[AntonT]

Thank you Mitchell. This is all very helpful. 

[Vis-á-vis]

Hi Anton,

As far as the standard for internal wet area waterproofing is concerned, then all rooms with a water supply but excluding kitchens, bars, and kitchenettes are considered a wet area and should be waterproofed to meet the standard. So yes your laundry and WC would be included.

Bear in mind these are construction codes. For a renovation, it is really up to you whether or not you waterproof the WC. You don't often see leaks causing significant substrate damage in WCs as they are normally spotted way before it becomes an issue. Still, the best practice would be to waterproof and it is a relatively cheap part of a renovation.

You don't need a floor waste outside of shower areas but if you do install one then you will have to put in a fall with a screed. I know in some states floor wastes are more common and generally mandatory in apartment buildings. If you don't have one currently then I would not go through the hassle of installing one.

If you have a building permit and a surveyor/building inspector involved then you will need to meet standards by waterproofing laundry and WC.

Personally, I would never install a floor over existing in a bathroom. You don't know the condition of the existing membrane, or if it was installed correctly.

Flooring systems themselves can't meet standards for a waterproof membrane because the membrane has to change plane and be continuous with no seams or joins. Even vinyl flooring is not considered to be a waterproof membrane as per the standard (AS4858).

[MitchellMc]

We appreciate your expert opinion @Vis-á-vis.

Many thanks for your input.

Mitchell

[AntonT]

That is really useful information. Thank you for your input.