Expansion joints in opus porcelain tiles

[Artisan Ceramic]

Hi, can I please ask for some advice. I am laying 70m2 of porcelain tiles in 4 size opus pattern.

The floor is one half new extension (floor levelled about 2 months ago), the other old concrete.

I am laying electric underfloor heating.

I have patched the old floor to make it as even as possible, then I am priming the floor and laying 10mm insulation boards on flexible adhesive, then four electric UFH mats linked to 2 thermostats and then SLC.

My question is how and where do I put an expansion joint in an opus pattern. Could I use a Silicon sealant in the same colour as the grout and apply to the top edge of tiles from right to left, or do I have to end all the tiles in one place and put a straight joint accross (if this makes sense).

Any tips on how to keep on the opus design on track over such a huge area. I usually use the 30,40, 50 method, but am a bit nervous at the huge area I need to cover.

Any words of wisdom would be gratefully received.

Many thanks

Steve

 

[Ian]

Best way is to use a Silicon colour matched to the grout (mapei). Also consider a de-coupling membrane for such a large area, porcelain should be fine without, just something to consider.

 

[White Room]

If you do any controlled joints they should be straight, cracks don't follow joints on opus patterns

 

[Artisan Ceramic]

Sorry, what is a controlled joint?

 

[Scott]

Same thing, an expansion joint is sometimes called a control joint as in it controlls the movement

 

[Artisan Ceramic]

Thanks for that - are you saying that I won't need one? If so, what will give if there is any movement? Could I put a controlled joint around the edges or do I need a horizontal straight joint?