Problems associated with cement grouts are efflorescence, rough joints, inconsistent (mottled) color, cracked joints, stains, soft joints and latex migration.

Many of these problems are caused by having to mix grout at the jobsite. The proper ratio of water or latex is crucial, as are proper mixing and slaking.

Mottled grout in particular can be caused by:

• Grout being mixed too wet.
• Grout drying too fast (lack of curing time).
• Overglaze in tile edges causing a variation in absorption.
• Tile setting materials being too high in the joint.
• Excessive cleanup water washing pigments out.
• Not allowing the grout to slake before commencing the grouting.

Cracked grout joints can occur from:

• Mixing with too much liquid, which results in shrinkage.
• Too much cleanup water.
• Thin grout lines which are not deep enough
• High tile absorption shutting down proper curing.
• Using a hard grout instead of a flexible caulking in dissimilar planes of tile.

Everyone expects a hard, firm grout joint. If you have a soft grout joint, it may be the result of using old material that has lost its ability to hydrate and harden. Cleaning with concentrated acidic cleaner may also be the culprit. Sometimes damp curing a soft joint will initiate hydration again and produce a hard, dense grout joint.

Don't Take Short Cuts

Most problems can be avoided by following the manufacturers' directions, dampening the joint prior to placing grotto and damp curing. TCA and ANSI guidelines ask for 72 hours of damp curing.

With the variety of grout colors available and the need to provide an installation acceptable to a critical audience, I would suggest that you do not take short cuts- which is very easy to do when grouting. This is the last part of the job, and time and money constraints may be pressing. Resist those pressures. As Malcolm B. says, "Do it right the first time."