How to Fix Grouting Mishaps

Wrong Consistency

• Properly mixed grout has the consistency of slightly runny creamy peanut butter. When scooped onto the end of a grout float, it should stay put, not drip or run back into the bucket. Grout is rarely mixed up too dry; when it is too dry it is difficult to stir and crumbles. Grout is frequently mixed up too wet, however. Grout that is too wet or runny does not cure properly, leaving the finished joints weak and prone to cracking or crumbling, as well as to efflorescence, a chalky, white appearance. If your grout is runny or too wet, add additional dry grout to the mixture until it reaches the proper consistency for use.

Weak, Cracked or Insufficient Grout

• Too much water in the grout, or too much water in the sponge as you clean the grout, may result in a partially-filled or weak grout joint. There may be holes, cracks or gaps in the grout lines, which can weaken the integrity of the joint and allow moisture to penetrate beneath the tiles. While it is tempting to simply apply more grout, new grout will not bond properly to grout that has already cured. To fix this problem, dig the old grout out with a utility knife or a grout saw. Clean the joint well with denatured alcohol to remove any remaining grout residue, then regrout the joint.

Excess Grout

• Grout begins to cure within 10 minutes of application. It dries to a hard finish within 24 hours, but does not completely cure, or harden to its final strength, for up to three weeks. If you have applied too much grout to the tiles or were interrupted in your grout job, leaving the grout to dry on the tiles, it can still be removed within a few days of drying. Scrape as much of the excess grout off the tiles as possible using the sharp end of a paint stick or other piece of wood with a sharp edge or angle. Soak the remaining grout in a mixture of one part sugar to six parts water until the grout softens enough to be cleaned up.

Haze

• No matter how successful your tile job went, you may discover a film of dried grout on your tiles the day after grouting them. This is known as grout haze. It is made up of tiny particles of the Portland cement left behind during the cleaning job. If attended to within a day or two of installation, grout haze can be removed with a dry towel. Crumple a paper or microfiber towel in your hand and work it in circles over the tile; the haze should wipe right away.

Sealing

• If you have used a cement-based grout rather than a presealed or epoxy-based grout, prevent another kind of problem before it occurs by sealing the grout. Grout can be sealed at any time once it has fully cured, or at least three weeks after application. Not sealing your grout could lead to staining or mildew buildup. Clean your grout well to remove any surface stains or mildew, then apply an impregnating sealer to the grout once yearly to protect it from stains.