Tell ya what-- how about if I put em all in one place? (or atleast copy em from one place to another!)

Q) What are the different types of tiles you can use in a bathroom and what are the advantages/disadvantages of each?

A) There are several types of tile available. They fall into two general groups: ceramic and natural stone. I'll take these one at a time:

Ceramic tile-- For purposes of this discussion, there's glazed conventional, unglazed porcelain, and glazed porcelain. All three are good tiles for bathroom use, but the porcelain is a better choice only because of its density and lack of water absorbsion, which makes upkeep and cleaning easier. Also, with reference to steam showers, you DO NOT want to use natural stone, being that the steam would tend to permeate into the stone even more readily than liquid water, and could end up giving you algae problems, as well as mold and mildew problems, unless you don't mind being tied down to your bathroom.

Natural Stone-- There are several types of stone that are used in bathrooms. It doesn't necessarily mean that they're all GOOD IDEAS for bathrooms, expecially the softer (and more absorbant) stones, such as slate or limestone. Now, I know I'm going to get a world of flack about this from epople who have bathrooms finished in these materials. I know they CAN be used.... so long as you're aware of the extra upkeep involved. But if you're someone who doesn't like to keep after things, you may want to pick an easier material to maintain. Generally speaking, the softer the stone, the more the upkeep. Limestone being the softer of the stones, and that would include travertine, next would be many slates (although some would actually be harder than even most marbles, such as brazilian and british slates), then marbles, with quartzite and granite rounding off the list as the harder and more dense stones that you could use.

Q) What should I be sure to look for when choosing tile for a bathroom?

A) Short answer-- something that you like! The bathroom is the one place that just about anything the showroom has can be used. The only limitations are basically the upkeep you want to put in, and slip resistance on the floors of your bathroom and shower. Now, although ceramic tile is basically maintenence free, you don't want to use something with a texture to it that will catch all kinds of junk in the shower, making it more difficult to keep clean. At the same time, you don't want to use a polished stone or bright glazed ceramic tile for the shower floor, either. These both CAN be used, but again, it comes down to upkeep for textured wall tile, and doing something to rectify the slippery floor.

Q) Where should I use tile and where not?

A) Tile can be used on every single surface in the bathroom, if that's what you like. This is all a matter of taste... for the most part. About the only place where there's a requirement is any place there's a showerhead involved. If tile is to be used either in a shower or a tub/ shower combo, The tile MUST go up to a minimum of 72" off the floor. Past that, it's up to the disgression of the owner.

Q) What size tile and what layout patterns to use in various areas?

A) Again, this is a subjective question that can really only be answered by the owner. The ONLY place where there's a recommendation for mechaincal reasons is on a shower floor. TCNA recommends that mothing bigger than 6" be used on shower floors due to the cone shape of the floor's pitch. In addition, most installers will request no bigger than 4", and prefer a 2x2 tile to work with on the shower floor. This is also advantageous to the homeowner who'll be showering in there, because the added grout joints will add more traction to the floor.

Now, I've heard many times that you shouldn't use large format tiles in a small area like a powder room floor, and if you have a wide open bathroom, you don't want to use real small tiles. My response to both is the same-- HORSEHOCKEY. I've done bathrooms both ways-- 24x24 diagonal in a 3' wide powder room, and 1" hex ceramic mosaics in an open 100 sq. ft. bathroom floor. The rule of thumb is if you like it, it's right!

Q) How do I find/choose someone to install the tile?

A) Many people will tell you to get names from the showroom you get your tile from. This is no good, unless the showroom is willing to take responsibility for the installer by either having them on payrool, or as a subcontract. Then they have something to lose if they give you a bad installer. Many people will also tell you to get references and to actually check them out. This ALSO doesn't work. I've been in this work for just under 30 years now, and I've yet to find a single installer who ever gave the name of someone they had a problem with. They say even a blind squirrel will find a nut once in a while. The same can be said for "fly-by-nights" and good work.

So if you can't trust recommendations, and checking references is a lost cause, what do you do? REVERSE THE PROCESS!! Instead of finding an installer and getting references, get references, and thru them, find your installer!! No matter where you live, if you drive around, you'll find constructions sites and developements. Stop and ask who the GC uses. Get a name and phone number. Sooner or later, after asking around enough, you're going to find that the same names will begin to show up time and time again. THESE are the guys you want to use. But don't expect a bargain price, and be prepared to wait, because these guys will be in high demand, even in the worst of times, and they may demand a bit higher price, but they'll be worth every penny, if for no other reason, just because of the peace of mind they'll give you in knowing you're getting a good quality installation. Ask anyone who's gone through this experience, good or bad-- that alone is worth its weight in gold.

Q) What are the proper underlayments for tile?

A) There are several, and I'll take them one at a time:

CBU (cementitious Backer Units)-- This is the term that generally covers all cement boards (such as Wonderboard or Durock) or cement fiber boards (such as Hardibacker). This is the most common used tile underlayment. Generally speaking, it comes in two thicknesses-- 1/2" and 1/4"-- and each has its use. !/2" must be used for wall installations, due to the fact that the 1/4" is way too flimsy with nothing to back it up, and would flex too much to last. Besides, the 1/2" CBU will usually match up nicely to most sheetrocks. The 1/4" is used for floor installations, unless the added height of the 1/2" is needed to match up to other floorings. Being that neither has very much structural strength, so long as the subfloor is 3/4" or more, the 1/4" CBU is all that's needed. Keep in mind that even though it's basically fiberglass reinforced concrete, the only thing it adds to the floor is a stable bonding surface, so the 1/4" will do just fine. One place where alot of contractors will try and shortcut is by using greenboard instead of CBU for shower walls. This is expressly forbidden in the IRC (International Residential Code) by the following code:

IRC Greenboard Code:
The 2006 International Residential Code (IRC) states in
Section R702.4.2 that "Cement, fiber-cement or glass mat
gypsum backers in compliance with ASTM C1288, C1325
or C1178 and installed in accordance with manufacturers
recommendations shall be used as backers for wall tile in
tub and shower areas and wall panels in shower areas."

The 2006 IRC also states in Section R702.3.8.1 that
"Water-resistant gypsum backing board [Greenboard] shall
not be used where there will be direct exposure to water."

Membranes-- There are several around that work well over many different surfaces. Most of them are what's called "Crack Isolation Membranes". Just about every manufacturer has one, from trowel ons or roll ons, such as Hydroment's Ultraset or Laticrete's 9235 or Hydroban, to sheet membranes such as Noble's CIS membrane. All will give the tile a little more protection against movement than just going over CBU. However, there's another class of membranes called "uncoupling membranes" of which the most popular by far is Schluter's Ditra, that are made from bonding two layers together, usually a fabric fleece backing and a plastic sheeting with dovetailed waffling to "lock" the thinset in place ( as opposed to accepting a thinset BOND). These membranes will, as their name implies, uncouple their two layers in case of movement, to save the floor, and for thinset floors, it's the most protection you can give your tile floor.

Plywood-- This is one where I get the most flack. I'm one of a dying breed that still believes in tiling directly over plywood. However, I can very well understand the reluctance of the industry to embrace this installation method, even though the TCNA DOES approve of its use for interior installations (Those with a handbook can check Method F-149). The reason I say that is it's a very "tempermental installation method. You need to be very familiar with what you're doing, or you risk failure. There are even many pros I wouldn't trust to tile using this method. Everything you do is important, from the species of plywood used, to the direction the grain is laid with relation to the joists, to how it's gapped, and a host of other specs, as well-- many of which won't be found in the handbook, and if you miss just one of them, you're flirtin with disaster. All in all, when people ask me about it, I tell them that with the membranes available, there's no need to go directly over plywood. There are other methods that will give you just as long lasting a floor, and aren't NEARLY as sensitive.

Mudset-- This is the oldest, and still, after THOUSANDS of years of use, the strongest installation method available. In a mudset installation, a minimum of 1 1/4" of mortar called "drypack" (mixed to the consistancy of damp sand) is either bonded to a concrete slab, or laid down over tarpaper or 6 mil poly with wire reinforcement, packed, and then screaded off to flat level (or pitched) subfloor. This is what most people see when tiling a shower pan. Initially, the mud will be a somewhat soft subfloor. But over time, if mixed properly, it'll be stronger than concrete.

Q) What are the proper tile setting compounds?

A) This is one where I could write a book. It all depends on what kind of tile you're installing, and what the underlayment is that you're going over. I'll give a generalized list:

Polymer/ latex modified thinset: For all intents and purposes, this is the "cure-all". For almost any installation the modified thinset, which is basically portland cement, silica sand, and chemical polymers added for strength, will work. There are some that are specialized, such as the lightweight non-sag thinsets (such as Laticrete's 255 or Mapei's Ultralite), or the high latex content thinsets (like Latictrete's 254 Platinum or Hydroment's Reflex), but with the exception of going over some membranes, there's a modified thinset for every installation.

Unmodified thinset: This is the same as above, but with no polymers added. It's usually used in conjunction with a liquid latex additive, but will also be used mixed with water for going over some membranes. It's also used as a bedding for all CBU's.

Medium Bed Mortars-- This is a relatively new class of setting mortars, used mainly for large format tiles, where the normal notched trowels just don't put down enough material, and with thinset, it would be too much, causing too much shrinkage as it dries, causing voids under, and poor bond to, the tile, but at the same time, there's not enoough room for a mudset installation. This mortar is usually used with either a 1/2x1/2" or 1/2x3/4" notched trowel.

Mastics and Premixed Thinsets: THESE HAVE VERY LIMITED USES!! Let me say that again-- THESE HAVE VERY LIMITED USES!! They work well for vertical installations, where the tile used is 8x8 or less, and it's not a wet area. ALL THREE of those conditions must be met!! I know just about every pail of type 1 mastic says it can be used in showers except for the floor. DON'T BELIEVE IT!! Also, both mastic and premixed thinset (which is just mastic with a fine sand mixed in to give it bulk) claim they can be used for floor installations. Unfortunately, for the amount of material needed under virtually all floor tiles to bond to the subfloor, neither of these will fully harden. I had a personal experience where I helped a sister in law across country, telling her husband exactly how to do his main floor, what to use, and how to use it. Unfortunately, he went to the big box store to get his tile and materials, and they talked him into using premixed thinset. I didn't hear about it until SIX MONTHS LATER when his tile and grout joints started showing cracks all over the floor. When he called me I asked him what he used for thinset, and sure enough, this is when he told me. I told him to pull one of the tiles, and SIX MONTHS LATER, IT WAS STILL SOFT!!! DOn't let them talk you into it!! Use the proper thinset, and don't try and shortcut your installation. You're spending alot of money for it to be "just practice"!!

Q) How do you deal with different thicknesses of tile?

A) Whatever it takes. I've used membranes, built up the amount of thinset being used, I've even doubled up tiles when it worked out that way. Whatever it takes to get the two tiles to be flush toeach other.

Q) What are the typical tools required to lay tile?

A) Generally speaking, this is a list for just about all installations. Some may require specialized tools, but this would be for all:

Proper sized notched trowel
measuring tape
chalk line
margin trowel
nippers
high amp low speed drill and mixing paddle (best would be 6 amp or better and less than 400 rpm)
several buckets
score and snap cutter for straight ceramic cuts
4 1/2" grinder with a continuous rim dry diamond blade for ceramic, anything other than straight cuts
wet saw (can be used for ALL cuts, ceramic or stone)
grout float
hydra grout sponges (2-- once for grouting, one for cleaning)
24" and 48" levels (for vertical work)
heavy duty extension cords
KNEE PADS!! :-)
screwgun or nailgun (where CBU will be used)

Q) What about tile spacing and types of grout?

A) According to Dave Gobis from the Ceramic Tile Education Foundation in Pendleton, South Carolina, there will finally be a new standard for ceramic tile next year. The tolerances are shrinking. There will also be a standard for rectified tile. Along with that, there will be a revision to the installation standards that will specifically recommend a grout joint no less than 3 times the variation of the tile. For rectified tile the minimum grout joint width will be .075 or just over a 1/16".

As for grout, there's only one thing that determines whether you use sanded or unsanded grout, and that's the size of the grout joint. Anything less than 1/8" you use unsanded grout. 1/8" or larger, you need to use sanded grout. The reason is that the main ingredient in grout is porland cement, which tends to shrink as it dries. In joints 1/8" or larger, the grout will shrink way too much and end up cracking ans shrinking into the joint. The sand give the grout bulk, and the sanded grout won't shrink nearly as much and therefore, can be used in the larger joints.

What is the difference between a water based sealer and a solvent based sealer? How do you know which one to use?

There are two important differences. First, the solvent based sealer is a "breatheable" sealer, while the water based is not. What that means is that the solvent based sealer will let moisture transmit back and forth , so as not to trap moisture in the stone or grout, while the water based sealer will not. The reason this is a good thing is that you don't want moisture getting trapped inside of a surface, and growing mold or mildew INSIDE. That's actually even a tougher situation to remedy than if it just grows on the surface.Secondly, both are what's called "penetrating" sealers, meaning they do their job by penetrating into the stone, and stopping solids from getting into the pores of the stone, thereby curtailing stains taking hold. Water based sealers will not penetrate NEARLY as far into the surface as the solvent based sealers will, and as a result, have to be replaced much more often. About the only time I'll use a water based sealer is if I'm installing something like terra cotta tile, or soft limestone, where I need a pre-grouting sealer to stop the grout from adhering to the face of the tile. Any other time, I'll use solvent based.

Q) What's the difference between ceramic, porcelain, and rectified porcelain?

A) Actually all porcelain IS ceramic. The difference is that porcelain is a much denser clay, fired at a much higher temperature, which makes for a much more durable (and less absorptive) tile.

As for rectified porcelain, the main difference is that all other tile is stamped out or cut to size BEFORE it goes into the kiln, where during the firing process, the tiles will experience some extent of shrinkage. Unfortunately that shrinkage is never uniform, and results in the sizing you always hear about. This is why the larger grout joints (3/16"- 1/4") are required for most tiles. With rectified porcelain, the clay is fired in sheets, and then the tiles are cut to size AFTER they're baked, which results in much tighter tolerances, and the ability to use much smaller grout joints.

Q)I read in this forum to use unmodified thinset under the cementboard for our floors before tiling, but DH read the instructions on the board to use modified. Just wanted to confirm that we are to use unmodified and also to ask why?

A)That's kind of a controversy in the industry. Most manufacturers say modified. TCNA (Tile COunsil of NOrth America) says unmodified works best, but then they defer to the manufacturer's instructions. The way I see it, the thinset under the cement board isn't supposed to bond the two surfaces. Matter of fact, you don't WANT them to bond. That's what the screws are for. It's there only to bed the cement board to take out vibration between the two layers, so the unmodified thinset makes alot more sense to me.

Q)Why don't you want them to bond? He asks," Aren't the screws there to hold the thinset while it dries?"

A)Once you bond the two layers together, you've for all intents and purposes, formed a new, thicker, single layer, and you've lost all the benefits of double layering the floor, that being the allowance for the slightest bit of lateral slippage between the layers to allow further isolation of the tile installation from structural movement.

This is the tile FAQ I did for the Building a Home Forum. There may be a couple of places where it gets a little repetitive, but for the most part, it's different questions:

1) Can I lay tile over lino/VCT/VAT?

Answer: There are those who say you can, and in some instances this is true. The problem is in properly investigating whether or not your particular case is one of those instances. There are so many variables, and ANY ONE of them could make your floor fail-- is your vinyl cushioned or not? Is it adhered well? In the case of lino, is it perimeter glued, or fully glued? Was there an underlayment used, or was it laid directly over the subfloor (ALL underlayments used for lino are no good under tile-- any one of them will make a tile floor fail)? When it comes down to it, it's a very risky proposition, and when dealing with the time and money investment required to install a new floor, why gamble with it? You're much better off to do it right and take out the vinyl, as well as any underlayment that might be involved, and then start your installation from the subfloor. This way you KNOW it'll be done so that it lasts.

2) How good is premixed thinset?

Answer: Premixed thinset is nothing more than organic adhesive (mastic) with a fine sand mixed in to give it some bulk. For wall applications where mastic is appropriate, It's fine, although I don't see any advantage over traditional mastic. But for the use it was intended, that being replacing portland cement based latex modified thinset, it's an extremely BAD idea, for several reasons. First, ALL mastics are formulated to be used in very thin applications. The thicker it's used, the longer it takes to dry, and for some of the heavier notches that are used in flooring installations, it never completely dries. I personally know of one case where premixed thinset was used on a floor in april, and the following november, it was STILL soft. ANY kind of pliability will cause flex in the tile, which will cause the tile floor to fail, allowing either tile tile, grout, or both to crack. Seondly, even if it's used in a thickness that WILL allow it to dry, all it takes is a little moisture. All mastics are water based, and any moisture will allow the mastic (or premixed thinset) to re-emulsify, again, causing a failure in the floor.

3) Can I tile right over plywood?

Answer: Yes, you can, and it's done on a daily basis. However, you really need to KNOW what you're doing. There are additional steps you need to take care of, as well as pitfalls to watch out for that either don't exist, or aren't as important when using backerboard (CBU-- cementitious backer units) as your underlayment. The thinset you use, how you lay your plywood down, how you SCREW it down, even the species and rating of the plywood used, all make a difference. HERE is a good article that might be of interest. (hyper link the word HERE to http://www.fcimag.com/fci/cda/articleinformation/features/bnp__features__item/0,,131422,00+en-uss_01dbc.html )

4) Do I really need thinset under my backerboard?

Answer: The short answer is ABSOLUTELY. The manufacturer requires it, and if, for some reason, there's a problem with the floor afterward, you've immediately lost any kind of warranty protection. Now, there's a big controversy in the industry right now concerning the TYPE of thinset to use. The manufacturers, for the most part, recommend latex modified thinset, whereas the Tile Council of America (TCA) recommends UNmodifed, or dryset thinset. The reason is that the thinset isn't there to bond the backerboard to the subfloor. If it were, then the modified thinset would make a difference. In reality, it's actually there to fill the paper thin voids between subfloor and backerboard, thereby eliminating another source of flex, or movement, and extending the life of your floor.

5) What size trowel do I need?

Answer: This all depends on the size and thickness of the tile, as well as how smooth or rough the substrate is, and how deep the embossed pattern on the back of the tile is. For the most part, 3/16" v-notch for ceramic mosaics (1x1 and 2x2) or mastic walls, and either 1/4x1/4 square notch or 1/4x3/8 for just about everything else. There ARE some exceptions though. If there is a question as to which you should use in your particular case, your best bet would be to go to johnbridge.com and ask one of the pros there. You'll be sure to get a good concise answer.

6) Do I spread thinset on the tile, the floor, or both?

Answer. Either or both. Usually floors are gridded out, and then the thinset is spread on the floor. It's alot easier and quicker. However, for those who would rather backbutter the tile, that's fine, too, as long as you flat trowel thinset onto the floor to "burn" it into the floor. In other words, you want to make sure you get a good bond by pushing the thinset into the "grain" of the floor, be it concrete, backerboard, or plywood.

7) Can I tile right over my brick fireplace?

Answer: Yes, you can. You might want to make sure the brick is clean and free of any contaminants, such as dust or soot (TSP-- trisodium phosphate works well for this). If the brick is painted, it needs to either be sanded, or if this is a renovation, sandblasted. Do NOT use any kind of chemicals to remove the paint, as they tend to leave behind residues that will inhibit the thinset bond later. Once the brick is clean, your best bet would be to flatcoat the brick with a latex modified thinset. This will do two things for you. First, it'll give you a flat surface to tile over, and secondly, it'll show up any errant bricks that might be sticking out too much, and they can be addressed before the tile is going up. Once the flat coat dries, you can take a rubbing stone to take care of any ridges in the thinset from the trowel.

8) Can I tile over sheetrock?

Answer: So long as it's not a wet area (i.e.-- tub enclosure, shower area, tub deck), yes, you can. Even stone tile will adhere well.

9) My tile's/ grout's cracking! What's happening? Can I just replace it?

Answer: ANY time tile or grout cracks, it's a symptom, not a problem, and just repairing the tile or the grout will not take care of it. Until the REAL problem is found and rectified, the same tile or area of grout will continue to crack, no matter how many times you replace it. 99% of the time, it can be attributed to seasonal movement in the structure, either under, or surrounding the tile in question, and the tile needs to be isolated from that movement. Sometimes it can be as simple a fix as adding soft (caulk) joints. Other times, it may be necessary to either add joisting, or beef up the existing joisting to minimize the deflection of the floor. What the fix is depends on the individual problem, but in all cases, again, the problem has to be identified and resolved before the cracking will stop.

10) Do I really need to seal my grout?

Answer: There are alot of contractors who will tell you yes, and still others who will tell you no. The reason for sealer is to make cleaning and maintenence easier. There has been a trend in recent years to use light colored grouts in the main floors of the home in order to match lighter colored tiles, and a sealer is used to prevent "wear paths"-- darkening of the grout joints in areas of main traffic in the home. Unfortunately, sealers will not prevent this. You're much better off to use either a medium or darker colored grout. As for using sealer in the bathroom, sealer WILL help, but again, over time, grout will discolor somewhat, or "age", and cleaners will be, for the most part, just as effective, with or without sealer. (Obviously, I'm one of those who doesn't believe in them)

11) Should I seal my tile?

Answer: Most tiles should NOT be sealed. Most glazed tiles, as well as porcelains, will not allow the sealer to absorb into the surface, and as a result, it dries on the surface as a white haze, which is a BEAR to remove. The only tiles which should be sealed are most natural stone tiles, quarry tile, or terra cotta.

12) What is "preslope" in a shower pan, and do I really need it?

Answer: In a shower pan, the slope is the pitch from the perimeter to the drain. This allows 90% of the water to run down the surface of the floor and into the drain. Preslope is for that other 10% of the water that seeps into the floor's surface to be caught by the shower pan (floor) liner. It's a slope that goes UNDER the pan liner so as to make sure that any water that gets through the surface will seep down the liner to weep holes surrounding the drain underneath the shower floor, where again, it will be directed to the drain's pipe. Without this preslope, the water sits in the bottom of the shower pan, where it can become a major area for mold, mildew, and bacteria to fester and become a bad health problem. So, yes, you really need it.

13) Can I use mastic in my shower, or over my tub?

Answer: Although on just about every pail of mastic it says "approved for wet areas", no, you can't. Mastic is used extensively in commercial projects for these kinds of areas-- places such as hotels, apartment buildings, college dorms, all use mastic in wet areas, because it's so much faster to install the tile, thereby reducing budget costs. However, they also have maintenence staffs, not to mention that these buildings get renovated every 5- 10 years, and from the contractor's standpoint, the work only has to be warranteed for one year. After that, it's not their problem any more. A home is a different story, though. You want your tile to last for years and years. Once it's up, you want it to STAY up, and last. The problem with mastic is that it's water emulsive, and even after being up for a while, it can still reemulsify, become soft, and even wash out, causing your tile to fail. It's one of the leading causes of tile failure in wet areas.

14) Is tile or grout waterproof?

Answer: No. Even with a grout sealer, most sealers used these days are "breatheable", meaning the moisture can transmit through it, both in and out, so even sealer won't make it waterproof.

15) How long do I wait before sealing?

Answer: This depends on the sealer being used. Because of the different formulations, different sealers require different wating times, anywhere from 3- 28 days, and the best advice I could give you is to check your particular brand of sealer for its recommendation. Generally speaking, there are two types of sealer base-- water and solvent, and the solvent based sealers generally require the shorter waiting period, but they're also much more expensive.

16) Should I use an isolation membrane?

Answer: To use an isolation membrane just as a general rule, it's not necessary. If you have any question at all as to whether or not there would be too much movement in your subfloor without it, then yes, it should be used, whether it be over concrete or wood frame. NOTE-- isolation membranes will greatly decrease the chance of your tile cracking if your movement is lateral (side to side-- in the case of concrete cracks, ones that open and close). However, there's not a membrane made that will address the problem of vertical movement. If you have cracks in a slab where one side of the crack is higher than the other, or in wood frame, where an addition meets the original structure, you'd be much better off to put in an expansion joint that that point.
17) Height of TP holders, towel bars, coat hooks etc etc.

Answer: The best advice is wherever they feel comfortable to you. About the only one that would be somewhat difficult to figure out when it's time to install is the toilet paper holder, and the general rule is about 24-30" off the floor, and 18-24" forward of the toilet flange. AS for the soap dish, you'd want to locate it somewhere where it won't be in the direct line of the showerhead spray, even though the traditional location (middle of the back wall, 6" from the tub) puts it right there. Putting it in the "line of fire" just gives water a chance to work its way behind the soap dish and shorten the life of your shower wall.

18) What kinds of tile can be successfully used outdoors (ie: on porches, patios) and any needed techniques for installing.

Answer: There are two types-- Vitreous tile, which has virtually no absorbsion, and porcelain, which only has approximately .05% absorbsion. As for installation techniques, the biggest differences are:
1), you want to use a thinset that gets mixed with a liquid additive, as opposed to one that's already modified.
2) you want to make sure you use either a polymer modified or epoxy grout.
3) You need to make sure the surface to be tiled is pitched atleast 1/4" per running foot, to make sure water doesn't sit on the tile.
4) In the case of wood frame structure (for something like a deck) you want to make sure you use a good quality waterproofing membrane made for exterior applications. Noble's Nobledeck ( http://www.noblecompany.com/ ) is a good example of this.
5) In the case of slab, you want to honor all expansion and control joints, making sure that you either position your layout so that a grout joint falls over them, or cut the tile along these joints, and either way, caulk them with a good urethane caulking. Latex or silicone won't be strong enough.
6) If there are any cracks in the concrete, or in the case of slab on grade, if you have alot of sand or clay in your soil, or any other kind of ground that's prone to minor shifting, and isolation membrane designed for outdoor applications would be a real good idea.
7) You want to make sure that you do the installation at a time of year where the temp(both air and surface) stays over 50 degrees F. Otherwise problems could occur.

19) Are there different kinds of sealers for different locations, such as bath/shower, floor, kitchen counters?

Answer: When it comes to protectant type sealers, any penetrating sealer can be used in all places. The differences come in the finishing sealers. Do you want the wet or dry look? High gloss, or satin (matte) finish? Smooth or nonslip?

20) Should granite countertops be sealed? If so, how do I do this?

Answer: Some should and some shouldn't. Your best bet would be to ask your distributor (or installer) whether your particular granite should or shouldn't be sealed. As a rule, though, if you put a wet sponge on granite, and when you remove it, it leaves a wet spot, it should be sealed with a good penetrating sealer, which can be wiped on with a soft absorbant cloth.

21) What is the difference between ceramic and porcelain tile? Which is best for indoor flooring and why? How do I know when I am buying a good quality, durable tile--are there ratings I need to be aware of?

Answer: In all actuality, porcelain IS ceramic tile, just made with a much denser clay, and fired at much higher temps. As for which is best, all around porcelain is the answer. It's harder, will take much more abuse, and won't chip scratch, or stain as easily as most others. In addition, it'll stand up to much higher and lower extremes temperature wise. However, especially for residential applications, most glazed floor tiles will stand up to whatever you have in mind. There are two indicators to the quality of the tile you're interested in, when it comes to glazed tile-- first, the PEI (Porcelain Enamel Institute) rating, which rates the hardness of the glaze on a scale of 1-5 as follows:
CLASS 0 - Tiles technically unsuitable for floors
CLASS 1 - Residential and Commercial wall and bare foot traffic
CLASS 2 - Wall and Residential bath floor, soft soled traffic
CLASS 3 - All residential floors and Light Commercial
CLASS 4 - Medium Commercial, Light Industrial and Institutional, moderate soiling
CLASS 5 - Extra heavy traffic, abrasive dirt, chemically more resistant
Secondly, although some may disagree, and there ARE exceptions, price is a good indicator. For the most part, you get what you pay for, and although two tiles may look exactly alike, there may be a big difference in the hardness of the glaze, as well as the density of the bisque, or body of the tile.

Q) We are having porcelain tile installed in our foyer (13"x13" tiles) and in our powder room (6'x6" tiles). Both are heavy traffic areas. Is there one grout that is better for these areas than another grout? New to my vocabulary - "sanded grout" and "unsanded grout"; "Portland grout"; "epoxy grout".

A) Although there are others, for all intents and purposes, there are two kinds of grout-- portland cement based, and epoxy. The portland cement based grouts are the conventional grouts that have been around for millenniums. Although in the last few decades, they've been modified with latex and other polymers to make them stronger and more resistant to mold and mildew, they're basically the very same grouts that have been used since Greek and Roman days. There are two kinds of portland cement based grouts. One is sanded, and the other unsanded. The only difference between the two is, as their names imply, the sand. The ONLY thing that determines which grout should be used is the joint size. NOT the glaze, NOT aesthetics, NOT the material (ceramic vs. glass or polished marble), NONE of those. I'll repeat-- the ONLY thing that determines which is used, is the joint size. Anything under an 1/8" takes unsanded grout. Anything 1/8" or bigger, you use sanded grout. If you use unsanded grout in larger joints, the cement in the grout will shrink way too much as the water evaporates out of it, and the joints will end up shrinking and cracking bigtime. If you try using sanded grout in smaller joints, the grains of sand will literally clog the top of the joint, and not allow the grout to get down INTO the joint, and the grout will flake off in a matter of days.

As for the Epoxy, most epoxy grouts use a much finer "sand", and therefore can be used in any size grout joint. Further, epoxy grouts are everything people say they are. They're much easier to clean, practically stainproof, and also extremely expensive. Most epoxies will cost atleast 4 times the cost of conventional grouts, and the installer will also usually charge a premium of between 1.50- 2.50 a foot for the use of epoxy grout. There are alot of people who will disagree with me, but my own opinion is that for most residential installations, epoxy grout is bigtime overkill. The ONLY times I'll recommend epoxy grout is first, if you're installing a tile countertop, and two, if you have animals in the house that either aren't housebroken, or are prone to accidents. In either of those cases, epoxy might be worth the money. For anything else, though, conventional grout is more than good enough.