Oudoor porcelain tiles

[leen...]

Hi All,

We are looking to lay porcelain tiles on a new patio. It has a concrete base so need to lay the tiles on top of that. Looking online I seem to be able to get 10mm and 20mm thick tiles which are suitable for outdoors. There are mixed messages about whether 10mm is suitable or not. Some sites say not and other say they are fine provided you use cement based adhesive. The 10mm ones seem a lot cheaper so wondering if anyone has any experience with using these?

Also, there is about 75mm from current concrete slab to where I would want the finished level. What is the best approach to make this up? E.g. should I assume say 5mm of adhesive so add a 60mm concrete slab on top of the existing one?

thanks

Lee.

[The Natural Philosopher]

Rearranged the post to deal with part II first

My personal feeling is that 50mm of cast concrete slab is probably the cheapest way out of this - chip up the base you have and build a level wooden frame about as you say tile plus 5mm, wet it thoroughly and fill it with concrete.

Think of the tiles as a skin on what is underneath. They are only as strong as the layer underneath, and that's why thin tiles with dot and dab wont be very good.

You need a very good cement based adhesive that is filling the space under the tiles as near completely as you can.

I used this to fill HUGE gaps on an uneven screed, under slate

The key to using this is to mix small quantities and take the job slow. String your areae to get lines to lay tiles too, tamp down each tile carefully to the strings and use a short level on every tile. If its below string lift and add more cement.

Lay about three at a time,. then uses a sponge and clean water to wipe off any cement on the tile surface and scrape any cement from between te tiles where you want to grout.

You cannot clean dried cement of the tiles with brick acid. You MUST use lots of fresh water on a clean sponge, and rinse after every single wipe.

The rapid set tile cements sets quickly - maybe 20 minutes and its unusable, so use the old cement to fill gaps under the edges and or as part of a new mix.

I estimate 1-2 sq meters per hour is as fast as you want to go to get top class results.

Leave overnight and grout the next day. Cement grout again. I like BAL grouts.

Or if you really want it rock sold use sand/white cement mix.