How to waterproof a masonite floor prior to laying vinyl tiles?

[The22vas]

I have a small bathroom which is 1.5 x1.6 m. 

It has a toilet and a shower in it. 

The toilet has been leaking through the waste pipe and leaving a significant amount of water on the floor for a number of years. 

I recently purchased this house and have uncovered this issue. 

After removing the vinyl tiles that were on the floor, I noticed there was masonite underneath which has been hammered to wooden floorboards under that. 

The masonite has damaged to it and in a couple of areas next to the shower there are signs of rotting. 

I want to remove the masonite, replace it and somehow waterproof the area so then I can put vinyl tiles on the floor. 

This is the second bathroom so it doesn't have to be more than just a fix. That is serviceable. 

Can somebody please provide being with some guidance on how to waterproof the floor and if the replacing the masonite with new masonite and then laying vinyl tiles is the correct solution. 

What is recommended to level the for where the rotting is occurred under the masonite? 

If I lay the masonite do I have to paint a waterproof membrane on top? 

Will the vinyl tiles stick to the waterproof membrane? 

I need some help and any recommendations would be appreciated. 

Please refer to images of the bathroom to show the damage and explain what I have to work with. 

    

[EricL]

Hello @The22vas 

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

I'm afraid this particular repair will take more than just replacing the Masonite. In order to properly repair your bathroom, the Masonite must be replaced with James Hardie 1800 x 1200 x 6mm 2.16m² Ceramic Tile Underlay Flooring or similar. This will involve the removal of your shower, toilet and vanity.

The entire room must be emptied out so that the water proofing can be applied properly. Please note that the application of waterproofing will need to be done by a trained professional as it will be inspected and signed off. At this point in time, I suggest speaking to a registered builder regarding the possible repair options open to you.

Here is a link to ideas and inspiration:  Top 10 most popular bathroom projects 

I also suggest having a look at this guide - How to plan a bathroom renovation by @Adam_W 

If you have any other questions we can help with, please let us know.

Eric

[The22vas]

thanks for the response... certainly not something i wanted to hear, but it all makes sense.

Does bunnings sell shower bases that are smaller than 900 x 900. 

i need something that is 800 x 800 at a max?

[EricL]

Hello @The22vas 

I'm sorry but the store currently does not have an 800-shower base. However, as an alternative, I propose thinking about building an enclosed shower using a false wall to create a shower cubicle to the size that you're after. I suggest making your cubicle slightly bigger to 840mm so that you can use the Estilo 900 x 1830mm Chrome Adjustable Framed Shower Screen which can be adjusted down to 840mm.

If you need further assistance, please let me know.

Eric