What material to use for new bathroom subfloor?

[Garen]

Hi Team,

Im replacing a subfloor in my bathroom and getting conflicting info in what i should be using. Ill list my project below

• 1950s house with floorboards and on stumps.
• Have removed the floorboards and repaired the joists etc
• Need to add new sub floor to get it ready for new floor covering, thinking vinyl, probs not going to be tiles.

Questions I have

• What subfloor am i using to begin with? Plywood, cement sheeting, yellow tongue? Have had lots of conflicting information.
• Do i need to lay another layer over the intial subfloor? Been told to use ply or cement sheeting for this, and also not needed. Been told this is for strength.
• After this theres water proofing and final covering, probs vinyl in my case. Is this correct?

Im getting trades to do some of this, but will do evrything I can myself.

I would love some help with this please! Any other information and tips would be great.

Thanks

[chriscam82]

fiber cement sheeting is your best bet for any wet area its just very very heavy so prepare to have someone help 

then you will need to

waterproof 

lay screed 

waterproof again 

then tile 

[MitchellMc]

Welcome to the Bunnings Workshop community @Garen. It's brilliant to have you join us, and many thanks for your question about bathroom subfloors.

As @chriscam82 mentioned, the standard modern approach would be to use Hardie's Secura compressed cement flooring. It will be laid directly onto the existing joists, though some changes/additions might be needed to accommodate them. Here's the installation guide.

You could use Hybrid Vinyl in non-wet areas, though vinyl sheeting is not an approved flooring for a bathroom.

Here's another useful guide: How to plan a bathroom renovation.

Please let us know if you have any questions.

Mitchell
 

[MartinM]

Hi @MitchellMc, I'm in a similar project, but I already removed all wall and subfloor. 

From your answer I understand cement flooring (Hardie's Secura) will be the recommended way to go. A few more questions:

1) is it recommended to tile directly over Secura sheet or is better to add in a tile underlay or mortar/cement mix?

2) for wall, is it better to go with Aquacheck (or similar) or Hardie's Villaboard?

Thanks!

Martin

[JacobZ]

Hi @MartinM,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

As per the Hardie Secura Flooring Installation Guide, it is possible to tile directly over Secura Sheet without a mortar bed or underlay, but you'd need to ensure that the recommendations for control joints are followed. Essentially, what this means is that your tiles cannot sit directly across the control joints; the gaps between the tiles need to follow along this control joint and be sealed with a suitable flexible sealant to ensure that the tiles move with the movement of the flooring. With a floating mortar bed, the tiles do not need to be laid out according to your control joints in the same way.

There's a little bit to it, but the installation guide has everything you'll need to understand. Have a read and let me know if there is anything you require clarification on, and if there is anything specific about your scenario that you are not sure about, please let me know so I can assist further or reach out to James Hardie for their assistance.

For your walls, either Aquachek or Villaboard can be used in a wet area, so it really comes down to personal preference and your budget. In saying this, Villaboard is the option that most bathroom renovators and builders that I have met tend to use.

Let me know if you have any further questions.

Jacob