Porcealin tile- floor prep questions

[Steves32]

I posted this in another thread & didn't get much input.
So- I'll cut & paste it here.
Getting ready to tile my floor in a few weeks.
I have expansion joints tooled into the slab. Very few cracks in my slab- been down for 18 months now. The cracks are in the bottom of the tooled joints.
I'd like to tile right over them. My tile guy says shouldn't be an issue but for peace of mind- recommended this stuff. Not cheap!!!

http://www.custombuildingproducts.co...ling-mat.aspx#
or this
http://www.schluter.com/6_1_ditra.aspx

Garage is 20x21 & tile size is still undecided. Looking at 3 sizes- 12x12, 8x16 & a 12x24. All PEI5

My question-
Is this mat overkill?
Is it necessary?
It will definately double the install price.



Here's pic of the floor.
Each square tooled in is about 7 ft square. Tooled joints are wide & deep. I'd say 1/2"w x 1/2"d.

Is it worth the trouble & expense?





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[210Hardtop]

I would use the Ditra, any movement will not crack the tile.

 

[Dakota00]

I went through your garage build and saw the concrete guys did a good job on prepping and pouring the concrete slab.

There's no need for Ditra on this reinforced concrete slab, all the cracking occurred in the control joints already. People fail to understand that Ditra is not guaranteed to stop cracking of tiles and grout lines. Ditra only helps on horizontal movement (which already occurred on this slab), any vertical slab movement Ditra will not stop the tiles from cracking.

Bottom line, prep the floor good, use a quality thin-set and start laying your tiles!!

 

[210Hardtop]

I went through your garage build and saw the concrete guys did a good job on prepping and pouring the concrete slab.

There's no need for Ditra on this reinforced concrete slab, all the cracking occurred in the control joints already. People fail to understand that Ditra is not guaranteed to stop cracking of tiles and grout lines. Ditra only helps on horizontal movement (which already occurred on this slab), any vertical slab movement Ditra will not stop the tiles from cracking.

Bottom line, prep the floor good, use a quality thin-set and start laying your tiles!!

So your saying there will not be any further expansion or contraction of the slab?
I'd still use the Ditra!!

 

[Dakota00]

Less likely when the OP lives in California.