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Reinforcing Soft and Crumbling Surfacing

Dealing With Cracking Grout and/or Surfacing!

( After reviewing each section below, see page bottom for general repair tips. )

Cracking due to movement:
(For cracking due to softness of grout, or lack of good bond to tile edge - see below)

Cracking through a grout joint and/or tile is most often caused by movement of the structure. This is seen most frequently at the juncture of wall and floor because the movement is along two planes. These surfaces move because of expansion and contraction throughout the day as temperatures fluctuate.

clean, protect, seal tile - stone - pavers - brick

The best answer is to plan for this in construction. Allow gaps at edges that are hidden by molding or cabinetry. If that is not possible (as in the picture above), there are flexible caulkings that are made to be used on exposed perimeters and match the grout color. Check with your tile dealer for "colored caulk".

If an existing installation, here are options to consider:

  • Fill the cracks with a non-sanded grout. This is much finer than sanded and may work better for small cracks and smoother textures.
    Use the same manufacturer and color as needed to match the grout. Use any that matches the tile or stone.
  • For large cracks in grout - patch with the same grout. Sand lightly when dry to blend texture differences.
  • Usually, there is no way to keep the structure from moving or flexing, so cracking is expected to occur again.
Soft or Flaking Surfacing - Cracking Due To Lack of Good Bond To Tile Edge:

In each of the cases discussed below, the answer is one of these sealers. In this sealer class,

  • "S-B-S Sealer" is lowest solids - little or no gloss
  • "Porous Stone Sealer" is higher - low to high gloss
  • "Mexiglaze" is the highest solids - medium to high gloss

Slates and other materials that flake and powder from foot traffic:

Notice the cleft into the slate that is at risk to flake off under foot traffic. The following also applies to any materials that have soft areas prone to turning to loose particles.

Indian slate showing a potential flake off
If applied per directions and chosen for the ability to penetrate down, any of Aldon's "solvent based" - "penetrating" class sealers will penetrate into these weak areas and tend to glue them down. If the surface is soft and tends to powder from traffic, these sealers can also prevent that from happening. Be sure to chose one that is not too high in solids content and will carry the solids down below the surface.

Some materials have soft areas that go so far down that the sealer cannot get down far enough to strengthen at that level. It is difficult to know this, so all you can do is the best possible to achieve good penetration. It might be a good idea to use (or start with) S-B-S Sealer even if a higher solids sealer would normally be your choice.

Grout or Mortar that is soft, cracking, crumbling
Brick, Tile, Stone that is soft and can erode away over time.
Cracking in floors and walls.

Any of Aldon's "solvent based" - "penetrating" class sealers will penetrate into weak areas and make them stronger. A soft material is made stronger and its bond to the adjacent material is also made stronger. Erosion is prevented because the material is made "hard" by the sealer.

Cracks in grout/mortar

If the crack is small so that the sealer can bridge it, use the highest solids Aldon sealer within the "solvent based" - "penetrating" class that is appropriate for your surface type.

Sealers are not heavy bodied enough to bridge and fill cracks unless the cracks are quite small and the sealer is one of our "solvent based - penetating" types. Cracks over 1/32" wide should be patched with mortar or grout. For small cracks an "undsanded" grout mix available at tile stores will be able to enter and fill them where the particle size of a "sanded" grout might be too large.

Using caulking is less desirable for patching cracks as it might interfere with the sealer penetration and bond, and you will want to seal after patching. One of our "solvent based - penetrating" type sealers will enhance the bonding of new grout to old grout and to the tile edges.

Some ideas for repairing and hiding severe cracking, pits, holes, etc.:

Sometimes you are dealing with a situation where the cracking is so bad that it seems the only alternative is tearing it out. Since you have nothing to lose, consider the following concepts:

  • The Aldon sealers listed as "densifying" ( see Surface Type ) will "glue together" loose grains and particles of "filler" material.
  • Your existing surfacing itself can provide "filler" material that matches in color and texture.
  • When patching with a filler material, use cement (or grout mix) and water as the binder. Do not use glue or caulk type materials as they can interfere with the sealer penetration that is done after patching.
  • If your surface type is a soft one (Mexican Tile, plaster, sandstone, etc.) - filler material can be generated by sanding. This should be done by hand so the surface contours are not flattened by a machine.
  • If your surface type is a hard one ( slate, concrete, dense stones, etc.) - filler material can be generated from another piece of the same material and smashing it into fine powder with a hammer (using all necessary protection equipment for eyes, etc.)
  • If the cracks are wide and deep, a caulking can fill them short of the final surface height. Then the filler material can be packed on top.
  • After the filler material has been packed and smoothed into the cracks, then the whole surface can be sealed at one time.
  • Test a small area. If the final finish is acceptable, you may not need to replace the whole thing.
  • Keep in mind that the original reason for cracking (earth or structure movement) is still unchanged and there may be more cracking in the future.