
When you can grout glazed cracked tile with razor sharp
edges flush, you are a grout master. This is nearly impossible with a sponge;
sawdust and burlap were used on this polymer modified sanded grout.

Both glass tile and swimming pools need special attention
for the proper selection and application of grout. One of the biggest issues
with any grout in a wet or exterior area is that of curing. The grout must be
cured prior to the introduction of any moisture.
Let’s start out by looking some of the common sense aspects of grout and grout joints. I mentioned sales personnel early as a problem and in my view, it is an ever-increasing area of concern. Big tile and patterns are the rage these days and the source of an increasing amount of complaints. Most end users desire very small grout joints; indeed, many would prefer no joint at all. Some are quick to point out that many old installations have tight joints and are a hundred or more years old. That is true, but the secret of very small grout joints used in days past is because the installation method, wet set mortar, allowed for such demanding tolerances of flatness in the substrate. In the old mud method, tile is beat into a level plane over a fresh plastic mortar bed. That is a rare luxury in today’s installations due to both structural and skill considerations. Using direct bond methods such as thinset, it is nearly impossible to affix an 18” tile dead flat where small grout joints would be satisfactory. Generally speaking, the industry referred to floor flatness standard of a ¼” in 10’, no more than a 1/16” variation in 12” works with 8x8 tile; you may even get lucky with a 12”x12” tile now and then. But, you should not expect regular success with a larger size tile unless additional floor preparation is done prior to the installation. Then there is the tile size variation to consider. Years ago we had 4x4, 6x6, and some 8x8 tiles. Given their small size, some minor percentage of variation was not a big issue, literally. Size variation is a fact of life in the tile manufacturing process as is warpage. A certain degree of each should be expected in all ceramic tile products, even rectified tile. On large size tile even while the percentage remains small, .075% under the new standards, that can add up as the size increases.
We thoroughly explained tile size variation allowances for both normal calibrated tile and rectified tile in last month’s Floor Covering Installer magazine. If you missed that issue, you may want to get a copy. And, keep in mind, rectified tile will have a specific allowable variation for the first time; there is no current requirement. Along with the new size variation limits there will also be a specific grout joint width recommendation coming in the new industry installation recommendations. That will call for a grout joint width three times the anticipated variation in the tile. Even with the new rectified tile standards that would result in a minimum joint recommendation of just over a 1/16” and roughly 3/16” for normal calibrated tile. From a practical point of view, to be a true Grout Master, you must understand the limits of the substrate and tile product on the grout joints well before the installation commences. If your boss, store, or retailer does not understand these limitations, you must educate them in the interest of remaining profitable while having happy customers.

On many types of grout, a grout bucket will do a superior
job to a sponge and pail. Don’t give up mastering the technique too early. Once
you do learn all the little nuances of this system you will never go back to a
five-gallon pail again.
While smaller grout joints is an increasing concern with the large tile preferred by customers, the largest concern remains the actual grouting process. Ideally, grout has two functions: to protect the edges of each tile by providing support and to provide a contrasting or complementary framework surrounding the tiles. Both are very important and the aesthetics and performance are dependent on the skill of the installer. Unfortunately, many contractors, installers, distributors, retailers and homeowners think that grout is also a miracle material that can absorb any movement, is stain-proof and probably the most common misperception; it will completely eliminate water or moisture penetration. To add to the confusion, the market is bursting at the seams with all kinds of grout products such as ready-to-use, plain, sanded, latex modified, acrylic modified, polymer-added, epoxy emulsion, and 100% solids epoxy. What does it all mean, and which type should you use? I don’t think there is a set answer to what is best; it really varies with application. The old standbys have always been unsanded grout for joints less than 1/8” and sanded grout for joints over 1/8”. While that holds true today, many new products have a wide range of joint size abilities, some from a 1/16” to ½”. There are also some “stainproof” grouts; a few additionally offer that there is no shade variation. These come in both cement and epoxy types. Mixing, application, and clean-up recommendations vary widely based on the formulation of the grout. When using hi-performance grout, strict adherence to instructions must be followed. In our training classes we consistently have demonstrated that old methods and techniques do not necessarily work on modern products. We have much less trouble teaching those new to the trade with no prior experience than seasoned veterans when it comes to new products. Sometimes it is almost comical how the newbie who read and followed the instructions with no preconceived notion outshined the “veteran” installer. We also demonstrate regularly that we can mix, install, and clean epoxy grout in less time than the most experience installer can do with cement products. We have done that demonstration a number of years and while it has been close a few times, the epoxy always wins! Any bettors?

Towel dragging is another technique that works well with
many sanded and epoxy grouts. By not forcing the sponge into the joints for
clean up, full joints are easily executed. On larger jobs, blankets are
occasionally used.
All grouts do share some basic similarities:
- Dye lots: Manufacturers use multiple locations and blend numerous different colors during the normal course of production. Always check the dye lot. On larger jobs you should blend bags dry to achieve the greatest consistency in color.
- Clean buckets and good potable water: The need for clean buckets should be self explanatory. Clean water can be hard to come by on construction sites with new wells. High amounts of chemicals good or bad can cause problems.
- Use of a low-speed mixing drill: Too much air results in weak grout. If you’re using a 3/8 drill, you are mixing too fast. 100 to 300 RPM is the range depending on manufacturer. Yes, recommendations vary.
With sanded cement grouts typically in use, there are a few added considerations that may affect shading:
- Overglazed edges on the tile: This is a common practice done intentionally by some European manufactures where the expose edge is used as trim.
- Glaze on self-spacing lugs in wall tile
- Porosity of the tile body. Impervious tile will prevents the rapid absorption of water versus a wall tile that will rapidly absorb it. There WILL BE a color difference.
Some other basic recommendations include but are not limited to:
- If a light colored grout is to be used, hopefully we installed the tile with white thinset.
- The thinset in the joints should be of uniform thickness. Troweling parallel to the tile and positioning your next piece directly next to the previously installed tile makes this much simpler to achieve.
- The tile should be wiped down with a damp mop or sponge. Moistening the surface prior to installation goes a long way towards easier cleanup. Otherwise the tile surfaces first exposure to moisture will be the moisture in the pigmented grout, not a good idea.
- Tile setters do not own fans. Grout must cure at its own pace. Fans cause rapid loss of water resulting in lighter color and weaker grout joints.
- Caulk all movement joints and inside corners prior to grouting. In wet and exterior applications a sealant should be used.

Stiff grout firmly compacted by three passes over the joint
followed by the driest method of residue cleaning possible will result in a
grout job of good color and high strength. Excess water in application and
clean up will leave the joint lighter in color and soft and powdery.
This is a subject that could no doubt fill a small book given all the products available and cleaning variations in use today. This article is not meant to be a definitive look at the rights, wrongs, and how-to’s of a somewhat complicated subject with so many product variables. However, it does cover the largest areas of concern based on the calls we receive. Sales people need to provide more realistic expectations on tile size variation and grout joint width recommendations based on typical substrates. Customers wanting very small joints with large tile should be aware of the premium price for such work. They also should better prepare their customers for the inevitable variation from the samples they use in selecting the grout. Installers need follow instructions set by the manufacturers to minimize grout complaints. It is much easier and faster to install grout correctly than incorrectly. This may sound strange, but it is true; it just takes a little planning.
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