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tomo13
Hi, have I dreamt this or does using Dural / Ditra eliminate the need for expansion joints ? Customer looking at limestone but doesn't want any expansion strips. Is a concrete floor with UFH. Thanks.
Dural - Expansion joints ?
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O
On one
Wouldn't have said so.If the concrete slab has expansion joints in you need to follow that through the tiles
M
m3fitter
This is correct.. but you'll find difference of opinions, i work for chartered architects and they all say different, i'm doing a church in newbury in September, and the architect states following expansion strips in line with the ones in the screed, with an 8mm expansion abutment at the perimeters, and then i'm working for an chartered architect in Kingston on a new build, and he states that ditra alleviates the need for expansion joints, note: they are both chartered ( which should mean the same standard )
rule of thumb: If there are expansion joints in the screed, follow then on the tile surface. full stop, if not, expansion on the tile surface only, will do nothing, or play safe and use expansion every 5m linear or through doorways with ditra. in a domestic instance, expansion joints look unsightly, in a commercial instance, it is a grey purchase, ie: its what has to be because the architect spec'd it.
rule of thumb: If there are expansion joints in the screed, follow then on the tile surface. full stop, if not, expansion on the tile surface only, will do nothing, or play safe and use expansion every 5m linear or through doorways with ditra. in a domestic instance, expansion joints look unsightly, in a commercial instance, it is a grey purchase, ie: its what has to be because the architect spec'd it.
D
Diamond Pool Finishers
M3 would i be correct in thinking that if an architect designs the expansion joint layout then they take responsibility for it ?
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tomo13
So does the membrane have to have a join where the joints are or go over then a joint in the tiles where the joint was ?
M
m3fitter
correct, in theory, but in practice, you follow, what has physically been laid in the screed, photo it
M
m3fitter
No because you are creating a floating floor, in lateral movement, therefore the screed takes care of itself, and your floating floor moves independently, it decouples
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tomo13
Are we talking expansion trims or a Silicon joint or something else ? Its going to be brick bond, so would run through the tile top to bottom not along a joint, not going to look nice really. looking at the screed today, all there is are lines in the screed about a disc blade width, surely it should of been bigger than that and with something in it if it was going to do any good ? Any photos of your previous would be nice to see.
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Mr Tiler
I watched a programme online about the stone masons who built the churches in this country... they basically used the same principle as ditra matting but with sand that is how they were able to make such floors. they didn't need the expansion joints for there floors so why would we need them on ditra? real question not being sarcastic if t seems that way sorry
S
SJPurdy
Quoting from Dural Special advise leaflet; "The matting MUST be split at the movement joint"
O
On one
Do you mean the concrete has been laid,cured and someone has Stihl sawed a line/cut in the screed?
Is it possible for the expansion joint to placed under a door? ie to less intrusive
Is it possible for the expansion joint to placed under a door? ie to less intrusive
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tomo13
Yeah looks just like that, is that normal ? I'm trying to find a way to get a copy of the plans on here so I could get some opinions of where to put them ?
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tomo13
Thinking about it they would of had to go pretty steady to avoid the UHF !
T
The D
Ditra / Dura is NOT a replacement for an expansion joint it is a crack isolation mat and allows only 3mm of lateral movement. If there is an expansion joint in the sub- floor you must follow with an expansion joint in the tile.
O
On one
Out of interest over what distance? or as a %. Not trying trip you up
I don't think it's a matter of opinion. The rules are laid out in various best practice guides including, including I believe, bs5385 ...
Out of interest over what distance? or as a %. Not trying trip you up
Only recall it from a video shown on Schluters 2day workshop. Although I don't believe its published as official,
Just bumping this thread. If it's not a current topic then don't worry about it for now. Other threads like this can be found in the main tiling forum. If you do want to reply to it, please do. Your information may add value to somebody reading the forum in the future.
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