Bad grout and mortar?

[Carrie29]

I just spent the morning helping a friend remove the bad grout in her recent ceramic tiling project. The grout was prepared and installed by the directions but it was just crumbling everywhere. The only thing we can think of is that the bags of grout and mortar sat in their greenhouse (140 degrees in summer) for a year. Now that the grout is out the most of the tiles can be popped right up. When you take one up you can still clearly see the ridges from the trowel. She said she stood on each one to set them but obviously they didn't adhere. The mortar on the backerboard seems firm. Do we need to take all the tiles up or just those that are very loose? Could the mortar and grout have been compromised by the high temperature of the greenhouse?
Thanks
Carrie

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[JTG]

Carrie
Welcome. Yes any mortar and grout over a year old is suspect. Standing on the set tile at the wrong time will release the bond right away. Go around the room and do a tap test on all the tile. If you hear a bunch with a hallow sound take them all up and start over.
Good Luck
JTG

[Carrie29]

Jerry:
Thanks. Assuming the vast majority of the tile can be picked up easily, would it be better to grind down the existing mortar and fix each tile or tear up the backerboard and start entirely over. What is the best way to remove hardened mortar? I used a plunge router to get the grout out.
Carrie

[JTG]

Carrie
It can depend on the type of CBU you have on how easy it will be to take care of the mortar. After you get the tile up see what happens with a puddy knife. If that takes the mortar off pretty good then go get a 4" razor scrapper or larger and take the mortar off that way.
If the mortar is REAL hard and stuck in place with almost all area of the floor covered the same you could fill it all level with mortar as you go along setting the tile. Skim coat with flat side of the trowel to fill it all in then use the notch side of the trowel to lay the mortar for setting tile.
If it is real hard but big areas came up with the tile you could do a thin coat of self leveler over the whole thing.
JTG

[doitright]

Hi Carrie :)

In addition to what Jerry said, it's also possible that the mix was too tight (dry), or skimmed over before the tile was set, or all of the above.

What kind of tile are they, and what is the size?