Expansion joint

[chas]

Couldn’t agree more with Julian. It’s laziness and bad management that screed joints aren’t below the door. At this point of the build there are drawings that if looked at would avoid the problem.

I think the client may have changed how the door opens but its not the first time ive seen expansion not correct but id have thought the

Movement joihts in

Sorry bad day. Was a bit rude of me.

In terms of the physics putting the joint under the door depends entirely on which side of the door opening the door sits. The joint in the screed should always be placed on the side of the threshold which has the largest dimension in order to avoid a larger movement causing restraint. So if the door goes from a small corridor into a large living room the joint will be flush with the walls forming the threshold on the living room side.. if that door subsequently opens into the corridor it's likely to be on the corridor side and the joint is in the wrong place. If the door sits mid threshold the joint is still in the wrong place. Putting the screed joint mid threshold would be pointless as it would not work. It's not laziness that puts the joint there its physics. If the door sits the other side then it's always going to be wrong for the tile joint.

One solution I've seen work loads of times is to use a piece of anti fracture mat across the doorway bridging the joint. A sort if localise crack bridge. The tile stuck to that will allow the screed to move laterally without the tile itself moving sort if like a slip joint where starter bars are used in concrete. One side is stuck fast the other side slips so the concretd can move without fracturing. It's not how anticrack mat should be used as it should be across the whole floor and I doubt you would get a spec from a manufacturer for it but it has worked countless times.

It does rely on the screed being free from vertical movement.

Hi thanks for all the comments i have my own ideas of what i am going to do just was interested in having another opinions. I have done shopping centre refurbs previously where the new layout would have tiles falling short or past previous expansion and we had been advised that as long as it fell within a minimal distance that it should be fine. Similarly the ufh has been run in the house any some shrinkage/ movement has already occurred so im hoping that the width of 40mm will not cause a issue. I know it perhaps isnt what is correct but it will look betterand b4 anyone mentions i know it isnt always a good enough reason but it also important to keep the customer onside as ultimately they are the one who will pay and you have to give them what they want with a measure of advice that it can result in tile failure or not as can also be the case. Anyhow enjoy weekend lads

 

[LM]

Movement joihts in

Sorry bad day. Was a bit rude of me.

In terms of the physics putting the joint under the door depends entirely on which side of the door opening the door sits. The joint in the screed should always be placed on the side of the threshold which has the largest dimension in order to avoid a larger movement causing restraint. So if the door goes from a small corridor into a large living room the joint will be flush with the walls forming the threshold on the living room side.. if that door subsequently opens into the corridor it's likely to be on the corridor side and the joint is in the wrong place. If the door sits mid threshold the joint is still in the wrong place. Putting the screed joint mid threshold would be pointless as it would not work. It's not laziness that puts the joint there its physics. If the door sits the other side then it's always going to be wrong for the tile joint.

One solution I've seen work loads of times is to use a piece of anti fracture mat across the doorway bridging the joint. A sort if localise crack bridge. The tile stuck to that will allow the screed to move laterally without the tile itself moving sort if like a slip joint where starter bars are used in concrete. One side is stuck fast the other side slips so the concretd can move without fracturing. It's not how anticrack mat should be used as it should be across the whole floor and I doubt you would get a spec from a manufacturer for it but it has worked countless times.

It does rely on the screed being free from vertical movement.

I can see what your saying. Most of the time I encounter joints that aren’t even square to the frame, the can run out 20mm in the width of a single door. In those cases I do as you’ve said and use a strip of anti fracture mat and put a joint in the tile in the middle of the subfloor joint, what else can you do. I’ve always got away with it so far.
Mapei use this method as a selling point in Mapetex.
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