Ron,
You’re confusing me, so in the USA they normally don't joint or they do joint.
Interesting, polypropylene fibres wouldn't be allowed within 100m of my slabs.
The way our system works is that generally for any class of site above A,S you require footing at regular spacing’s. This regular restraints position ensure that the cracking minor in nature. For A,S class sites I may consider a joint.
Ron,
This is one of the main brands of tile adhesive used in Australia. Recently changed its brand name from ABA to Ardex. I don't know if it is available in the US, but there would be similar products there. Per capita, Australia is a much bigger consumer of tiles than is the US, mostly because of the climate, but I would think Florida would be similar.
Ron hit many a nail on the head, and we do similar forensic work it seems... I do inspections sometimes in several homes a week all over the state, and cracks in tile are often worrisome to the homeowners, but we usually chalk it up to cracks in the slab telegraphing through the tile, and sometimes possibly due to poor workmanship in mortar coverage that causes cracks due to foot traffic.
Hokie- The further south you go in Florida and the closer you are to water, the more tile you see. I am pretty sure its a cultural thin in South Florida with the Latino majority and their Spanish architectural traditions (many more tile roofs, CMU and stucco walls, etc.) Now tile is pretty much standard in wet rooms and in many common areas, with laminate and real wood flooring making in-roads, especially with the improvement of laminate flooring quality and low price of material and installation.
I rarely see control joints in residential construction, sometimes in garages but very rarely in the house. Structural engineers have been pretty well kept out of most residential construction, and if its not required by code its not likely many contractors would do it, or know how and where to do it correctly. It would take coordination with the architect to align the joints with flooring transitions or walls but it could be done. Or you could let the slab crack where it wants during curing and then chase the cracks with a grinder and epoxy them, but NOBODY is doing that.
When I do a forensic investigation and people are having tile problems because of cracks in the slab, I give them the options and also warn them about the lack of guarantees.
I've also seen a lot of tenting and de-bonding failures, but that is its own subject. Had it happen on a rental property of mine. I did 4-5 repairs and then gave up and removed all of the tile (myself), did laminate in one room and did an epoxy coating in the rest. It serves its purpose, which is as little maintenance as possible..
Ron- For your current investigation with tile debond, slab "compression" or shrinkage due to PT stresses a possible contributing cause of the tenting tile, or is that confidential at this point? I have always thought with regular SOG that is on the low end of probably contributing causes of tile debonding. Workmanship is on the high end, and long-term tile expansion due to moisture re-absorption.
I think one statement from the Oz structural brethren is worth repeating:
"...unjointed slab with 0.3% reinforcement in a 100mm thick slab..."
This will result in fewer visible cracks, and control of crack growth.
When residential slabs are indeed reinforced in the US (probably less than 1/2 the time), it is not anywhere near 0.3%. More like 0.18%. Maybe.
a2...the PT has little to do with the debonding as it occurs in both directions; whereas the PT is one direction only. Would be interesting to be able to measure strand relaxation and correlate to overall shrinkage to see whether the chicken or the egg came first.
I agree that more often the issue is workmanship; however, there is a correlation to the amount of volumetric shrinkage of the concrete (lots of water in the mix)and the incidence of debonding.
I will be installing floor tile in our master bath this summer, so I'm going to use adhesive instead of thinset to see how it works. I anticipate it will work just fine...just don't know why it is discouraged by the tile industry in the US.
