Expansion Joints

[alex1963]

i've done a lot of extensions where old concrete meets new and i always run a grout joint along the concrete joint with colour marched silicon,if you do it right you can barely pick it. only problem would be if the concrete isnt tied in properly,but then it would be the builders problem!!

 

[DHTiling]

Ditra will not overcome this problem mick...it is a crack isolation membrane and vapour equalisation membrane .. It will not act as an expansion substitute...
The builders should have put an expansion point where the old meets the new..no other way around it, apart from if they had laid a complete new floor throughout...You need to determine where they join at and put an expansion joint at this point be it a profile trim or Silicon joint....good luck...

 

[Turkish]

Whilst on this subject, when tiling a floor where it`s not possible to remove the skirting boards to put the tile underneath, is it correct to tile up to a few mm from the skirting then Silicon that joint instead of grouting it?:huh2:

 

[brian c]

2-3 mm Turkish m8 and Silicon as you say.

 

[Proper Job]

dhceramics is spot on Who ever says you don't need expansion joints is talking ********. Your going to get some kind of movement in the floor over time. Some really good advice has been given here. Schluter make great systems and are top quality and you pay the price. I would leave the floor for 6 weeks from when it was laided by the builder, you could if you wanted make an expansion joint your self in the floor using an angle grinder and grinding a line where the two floors meet and place some silicon in there good qaulity silcon will go up to 25 - 30 % expansion, When you come to tile the floor make sure you well prime it and place either an expansion strip over the top of the exsisitng one or use silcon as suggested mapei do silicon to match the grout and you can't tell. Best of luck mate