How to build a base for tiling?

[jocon]

I wish to extend width of outdoor tile area (on concrete base ) by 800mm

Plan to rawl bolt subframe 150 : 50 subframe @ 400 centres to existing concrete base on one side and retaining wall on other side

What backing sheet product should I use on top of this sub frame to handle 600mm tiles

[MitchellMc]

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

For your extension, you’ll want a sheet product that’s designed to handle both outdoor conditions and the weight of tiles. A great option would be Fibre Cement 2700 x 600 x 19mm 1.62sqm Lightweight Durafloor Flooring. It’s strong, stable, moisture-resistant, and suitable for tiling over in external applications.

Since you’re planning to lay 600mm tiles, it’s important that the subframe is nice and rigid with centres kept at 400mm or less, just as you’ve planned. That way, the fibre cement sheets won’t flex under load and your tiles will be well supported.

Make sure to fix the sheets down securely according to the manufacturer’s instructions, leaving appropriate expansion gaps, and use a flexible tile adhesive and grout system designed for exterior use. That combination will give you a long-lasting tiled finish. Here's the Durafloor installation guide.

Please let me know if you have any questions.

Mitchell