Tiling an entrance porch

I have an outside (but sheltered) entrance porch. The cement finish was badly stained by some planters and it looks pretty crappy despite considerable efforts with a pressure washer and various chemical treatments.
So I'm starting to think about covering the mess with some decent granite or slate tiles. Any general pointers (do's and don'ts) would be most welcome.
However, I do have one specific concern -- the area in question comprises of 3 concrete slabs with expansion joints. To make matters worse, one of these runs at a 45 degree angle to primary axis of the entrance. One of these joints shows some signs of past movement. I suspect the outside slab settled a little probably soon after construction (about 17 years ago). There's an 1/8th inch crack along the joint. I think it's now stable and has not visibly moved in the 3 years I have owned this house.
How should I handle these joints? Initially, I assumed that tiling over the joints would prove fatal and that I would have to tile each slab seperately. The 45 degree joint would make the effect less than wonderful. But maybe it's okay to tile over the joints if I install some kind of isolation layer?
I'm sure that plenty of folks have tried tiling over old concrete pation, pathways etc. What worked, didn't work, and how did you handle the existing joints?
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| Malcolm Hoar "The more I practice, the luckier I get". |
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Malcolm Hoar wrote:

I tiled my concrete patio slab several years ago and here's what I did. Fill the joints with the thinset mortar that you use to adhere the tile, cover the whole slab with one of the several anti-fracture membranes available these days, install the tile using latex modified thinset, and keep your fingers crossed.
I've always figured that putting a hard yet somewhat brittle finish like ceramic tile over anything that has potential for movement is a crap shoot. But the things I mentioned can certainly help towards mitigating the possibility of cracking. It's been about 2 years since I did mine and no cracks, knock on wood. Some grout came loose in a spot or two next to the wall.
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wrote:

Thanks muchly for the comments. That all makes sense.
However, I've since realized that my job is further complicated by the fact that tile plus thinset plus membrame will add significant thickness. As a minimum, I'll need to shave that amount off the siding to prevent it from wicking up any water. And the drop (or lack of it) from the door threshold to the new surface could create even worse moisture problems at the front entrance.
Beginning to think about a good quality decorative epoxy coating...
I did my garage floor 3 years ago with a cheap one part epoxy paint. It hasn't lifted, flaked or chipped at all -- I cannot see a single spec of bare cement. But water runnoff from the vehicles has stained it pretty badly and sadly it's starting to look pretty tatty. These products seem to get pretty good reviews:
http://www.armorpoxy.com /
No rush if I go with an epoxy coating -- I'll wait for the warmer weather next year and more reasonable cure times.
As you say, tile is going to be something of a crapshoot which is not good given the amount of work installing the tiles and addressing all of the potential moisture issues.
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