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Grout, grout and grout

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Discuss Grout, grout and grout in the Tile Adhesive / Grout Advice area at TilersForums.com.

T

Tile Shop

Not exactly. It means its stronger, but not necessarily more flexible. The way I've been told (but am open to more scientific explanations if anyone has them) is that if it takes more N per mm2 to cause it to "snap", it has a higher density and is more rigid. If the EN196 test was to be done side by side, the polymer modified cement based sample would start to flex long before the epoxy...... but the downside is it would snap sooner.

In a real world installation, if there was any movement in a floor or wall, the epoxy wouldn't "buffer" the movement because it is too rigid, it would just transfer the stress or tension to the tile.

Ok, so lets look at it this way. If we could have a sample "rod" of UCP and KP of equal length, balanced between two equally spaced supports, with an equal 8N force pulling down on it, which do you think will be bending the most? the least rigid or most rigid?

Flexural strength is all the factory can give you but its a rough guide when you know a product has a flexible polymer built in. As far as I am aware there is no test for actual flexibility as it is not a requirement.
 

Simon Dale

TF
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Polymer modified cement based grouts are more flexible than epoxy. Or at least they are in Mapei's case.

Kerapoxy vs Ultracolour Plus as an example:

Flexural Strength (N/mm2): KP = 31, UCP = 9
Compressive Strength (N/mm2): KP = 55, UCP = 35
Hi Paul. Posted this on the TT forum hope you dont mind ? No name mentioned just the facts :)
 
T

Tile Shop

It doesn't exactly. But a grout that can resist that much flexural pressure ain't gonna be that flexible is it. Its rigid, its higher density and solid as ****. Grout needs to have a lower denisity and capillaries in it to allow flex and limited movement. Epoxy doesn't have that.

Like i said, there isn't a test for actual flexibility defined by any standards, but the flexural strength is a good indicater.

Don't have to take my word for it. Ask Bal, ask Mapei, ask Ardex..... Or do your own test.

Rule of thumb i was taught and have stuck to for 20 years:
CG1 - not flexible
CG2 - flexible
Epoxy - flexible but nowhere near as flexible as CG2
 

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