large floor movment joints ?

**terry the tiler** · 22-12-2011

Hi , I ve a large floor to quote (concrete sub) kitchen running through to the hallway , and need to know the max mtrs before i would have to put an movement joint in ? i Estimate the job to be around 25 mtrs , concrete floor. tiles are going to be trav or limestone. no ufh.

**Rich** · 22-12-2011

Between 7-10m of continuous tiling if Im not mistaken. Are there any joints in the screed?

**kilty55** · 22-12-2011

every 5 metres for me

**Ajax123** · 22-12-2011

10 meters max bay length, max square meters 40m2 max aspect ratio 2:1. bear in mind these are maximums and i always say just becasue you can does not mean you should. i would personally cut this in half and go for max 5m with max 20m2. you need a joint in your doorway anyway.

is it new concrete or old?

**Rich** · 22-12-2011

I should have said max.

**Phil Hobson** · 22-12-2011

Hi Terry, most people would go with BS:5385 maximum tile field no more than 10m2 in any direction, but I would go with my own gut feeling. Perimeter expansion is a must, doorways should be broken by expansion joints, just my opinion, corridors with perimeter joints 7/8 lin m. I like to err on the side of caution. As you have no ufh, I would go with BS recommendations.

If there are no expansion joints in the concrete subfloor then you should be OK with just perimeter joints,I would still install them in any doorways, just to be sure. Hope this helps.

**Phil Hobson** · 22-12-2011

Oh sod, I must have started typing my reply minutes after Terry asked the question. My typing must be getting slower, at least I think we all agree more or less.

**terry the tiler** · 23-12-2011

Thanks for your reply's . Theres no joint in the Concrete and its been down a few years. when setting out i will dry lay from the door first and see how the cuts work out. do you alwase put a joint in the door ways? what if when setting out it looks best with a full or 3 quarters of a tile running through the door way and theres no joint in the concrete ?

**Rich** · 23-12-2011

I dont install them in the doorways unless the floor needs to have a joint (that said, it would do no harm), then it is much easier to install an expansion joint without it standing out. Are you going to be using a pre formed expansion joint profile or silicone? More often then not you can find a colour matched silicone to the tile or the grout so that you would hardly notice it. Its an option if the setting out doesnt lend itself to joints in the door ways.

**jjoc** · 23-12-2011

how does eveyone get away with using a pre formed expansion joint on a domestic job. When I've mentioned them to customers they have always been very dismissive of having an expansion joint on show in their home - a really tricky one on a domestic job as I can understand their concern in a way. Spending out on some expensive naturalstone that they want to look uniformed and continous - then being told they need expansion joints every 7m or so. What does eveybody do?

Gall.B · 23-12-2011

Silicon joint colour matche with grout.

Kmow what you mean the domestic punters dont like the idea of expansion joints and get flusterd.
I normally email them some pics if they are concerned and show possible options.

I normally go for between 5 7 metre before expansion depending on sub-floor as Phill says go with your gut.
Have been on some jobs mainly car showrooms where the spec is 4 metres.

**Billy Hunt** · 23-12-2011

You can get some good matching movement trims now days,scluter do good ones to match grout and to be honest one in a doorway isn't that noticable,especially if you can get full tile both sides,better that than cracking tiles 3 months down the line.

**Phil Hobson** · 23-12-2011

A couple of examples, some preformed, some home made.

**Ajax123** · 23-12-2011

to be fair most people dont put joints in door ways and most of the time they get aay with it. i just dont see the point in offering advice about what you might get away with so will always try to advice based on correct best practice. The reason for the joint is not so much to do with expansion as it is contraction. As your tile adhesive dries and your tile face move during the thermal cycling of the room the whole thing will move. this happens much more slowly of course if no underfloor heating is present. The door threshold represents a "restraint point" where there is an abrupt change to the aspect ratio. There should be a joint in the concrete at this point also but if there is not and t has not cracked in anyway you are likley to be reasonably safe. However this will be the weak point in the floor so if it is going to crack at all it is likley to happen here first.