expansion joints

[bluevin123]

I am laying 50m2 of Trav floor and just want to know when to use expansion joints, I know what they do, but what are they actually made up of?
Is a bead of Silicon ok? excuse me for my ignorance but this is the first time I have came up against this. It has all been screeded on top of underfloor heating.

I am laying 600x400 in a brick style but they are going to run across the rooms meaning there wont be any straight runs in the doorways etc.
I tried to attach a picture but for some reason it wont let me upload it.
Anyway,hope you can help.
Cheers,
Vin.:smilewinkgrin:

 

[foxman]

Ho, is the floor wooden or concrete

 

[bluevin123]

Hi Foxman,
Its on concrete mate.
There is no skirting down, so I was thinking maybe a perimeter expansion joint then put the new skirting on top of the finished tiles.
Cheers,
Vin.

 

[White Room]

It's a screed floor not concrete, concrete is a base not a topping Please Please know the difference.