Ceramic tile that are severely cracked, spalled, or otherwise damaged are commonly replaced rather than repaired in situ. It’s best to find tile that matches the existing tile aesthetically and has similar compatible material properties. Tile can be replaced with new stock, old stock, salvaged, vintage, or historic replica tile made by specialty manufacturers. Care should be given to preventing damage to tile surrounding those being removed and replaced.
New tile should generally be replaced to mimic the existing system. Prior to the advent of thinset mortar in the mid-20th century, tile was installed in a thick bed of fresh mortar. Wall tiles would be adhered in a bed of mortar directly to a masonry substrate or over expanded metal lathe. Floor tile would be set in a thick bed of fresh mortar over a cementitious setting bed or screed. Grout was then installed between the set tiles.
Rare and distinctive ceramic tile that have shallow, superficial damage can be repaired in situ. Cementitious repair mortars or epoxies can be used to fill voids after proper surface preparation, which is necessary for durable bond. Glaze can also become damaged independently from the clay body. Repairing damaged glaze helps protecting softer, more porous historic tile from greater water absorption and damage from cleaning and use. Specialty coatings designed for ceramic substrates are available to fill areas of glaze loss.
Grout deterioration and loss is normal over time. Being the sacrificial material in the tile assembly, it’s best if cracking and damage occur in the joint rather than the tile. Joints should be maintained regularly to prevent water infiltration (during cleaning) or destabilization of tile. If grout removal is necessary, joints should be removed carefully with hand tools or appropriate power tools so tile aren’t damaged.
Coatings aren’t necessary for tile floor maintenance. However, waxes or penetrating sealers are used to protect floor tile depending on the type and condition, foot traffic, slip-resistance requirements, and maintenance regimen.
Regular sweeping and vacuuming reduce grit that can act as an abrasive, helping preserve the tile or glaze surface. Regular damp mopping and wiping down tile with warm water prevents deep staining over time. When deeper cleaning is necessary, it’s best to begin with the least aggressive cleaning material and method and work toward a more aggressive cleaner only when necessary. It’s important to test cleaning materials and methods in a small and inconspicuous place before cleaning. Abrasive and chemical treatments can damage the glaze or tile surface, as well as weaken grout joints leading to tile destabilization. Tile can also be routinely disinfected when desired.
With repair and restoration projects, it’s important to understand the properties of the existing tile prior to selecting replacement materials and repair strategies. The following field and laboratory testing may be needed for tile evaluation.
FIELD TESTING:
LABORATORY TESTING:
- Compressive Strength, Density, Porosity
| - Breaking Strength, Modulus of Rupture
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