Do I need an expansion joint?

[Spirit]

I will soon be tiling a kitchen/diner with 330mm square glazed porcelain tiles. The floor is concrete, overlaid with Wedi board and T2Red UFCH. The floor is 6.3m x 3.8m. The tiles will be laid before the kitchen and skirting boards are fitted, so a 5mm gap will be left around all of the edges.

It is an insurance job and the insurance assessor said that there should be an expansion joint in the middle of the floor, dividing it into two squares. I have never fitted an expansion joint in a floor a small as this before, is it necessary?

[IGTiling]

An expansion joint is required every 4 to 5 metres only if underfloor heating has been installed. If there is no underfloor heating then an expansion is required every 10 metres.

[Oli]

If the assesor is going to check and sign it off before you get paid mate, then sitck one in anyway, needed or not, last thing you need is them saying there not paying out after you've done all the work because they dont agree with the way you've done it.

[grumpygrouter]

Originally Posted by Spirit

I will soon be tiling a kitchen/diner with 330mm square glazed porcelain tiles. The floor is concrete, overlaid with Wedi board and T2Red UFCH. The floor is 6.3m x 3.8m. The tiles will be laid before the kitchen and skirting boards are fitted, so a 5mm gap will be left around all of the edges.

It is an insurance job and the insurance assessor said that there should be an expansion joint in the middle of the floor, dividing it into two squares. I have never fitted an expansion joint in a floor a small as this before, is it necessary?

If you are using the centreline as your starting point, don't grout that line, use a colour matched silicone sealant instead. Otherwise you might want to invest in a "proper" joint from the likes of Schluter and pass on the additional cost. or even lay Ditra/durabase instead and decouple the lot!

[Spirit]

The insurance have already paid the customer for the claim. The total job has been changed by the customer as she wants different kitchen units, UFCH etc and the insurers were happy her the quoted amount for reinstatement. My question therefore is not about keeping the insurance happy, just about doing the job properly. (The tiling is as per quote so Ditra is off.)

[IGTiling]

Leave one grout line in the middle of the floor empty (without grout) and put a silicone bead that matches the grout into this - this will fulfil the requirements of installing an expansion joint.