How to seal a Hardie Secura flooring sheet?

Question

I have a Hardie Secura Flooring Sheet that I plan to use as a benchtop for an old brick barbecue. There is currently a timber benchtop which has failed even with 6 monthly oiling. It is exposed to the elements so I plan to seal the flooring sheet and then tile with 600 x 300 porcelain tiles.

What should I use to seal the Hardie Secura Flooring Sheet?

Is there anything else I need to consider?

https://www.bunnings.com.au/james-hardie-2700-x-600-x-19mm-hardie-secura-flooring-sheet_p0851522

MitchellMc · Answer

Hi @dunc,

On the rear edge, the simplest option is to seal it with a waterproofing membrane or paint it. As it’s not a visible face, that’s usually more than adequate.

For the front edge, there are two good options. The first is to cut your tiles into thin strips and tile the front face. That gives the best visual finish and protects the edge properly. The second option is to use a trim. This doesn’t have to be complicated; a tiling trim or aluminium angle fixed to the edge would work well. If the timber cladding is being brought up inline with the sheet edge, the trim can sit neatly behind or above that to keep everything protected.

There isn’t a specific proprietary edging required, it’s more about ensuring the edge is sealed and mechanically protected.

Mitchell

dunc · Answer

Hi Mitchell,

Thanks for the detailed reply.

As far as waterproofing goes, I was mainly worried about the edges. They will be exposed and I will need to cut the length down so any protection that it comes with would be lost there. The bricks on the front of the BBQ are clad with horizontal timber, so one option was to bring this up inline with the edge of the sheet. I'm not sure if there is some kind of trim or edging option? Something I'll need to look into.

Here is a picture of how it looked prior to the weather causing the top to fail.

MitchellMc · Answer

Welcome to the Bunnings Workshop community @dunc. It's terrific to have you join us and many thanks for sharing your question on Secura flooring sheets.

You don’t actually need to seal the Hardie Secura sheet itself for this application. Hardie Secura is designed to handle moisture and is perfectly suitable as a substrate for tiling, so you can tile directly over it using a quality exterior-rated tile adhesive. However, you must first prime it.

If your goal is to make the benchtop more water-proof, you could apply a waterproofing membrane before tiling, but it’s not strictly necessary for the sheet itself. The more important part is managing water penetration at the finished surface. Sealing the tiles and, more importantly, the grout will do far more to prevent moisture getting into the substrate over time.

A few other things to consider: make sure the sheet is well supported underneath, follow James Hardie’s fixing requirements, use an exterior-grade flexible tile adhesive and grout, and allow for movement where the benchtop meets the brickwork. With those steps in place, the setup should perform far better than the previous timber top in an exposed environment.

Please let me know if you have any questions.

Mitchell