Although the best way to repair holes in tile is to replace the tile with one that was saved from the original batch doing so is often not possible.
In this case you have two options you can either replace the tile with a similar one that you find elsewhere or you can patch the tile. In this HowTo we will cover the proper way to make a patch with mortar to an existing damaged Terracotta Tile.
Choosing to make the repair will extend the life of the tile and allow you time to search for a good matching tile that can be used as a permanent replacement.
Inspecting the Tiles
Damage to a tile could occur from imperfections in the clay that do not show themselves for some years or it could be from impacts and installing accessories in kitchen and bathroom walls.
To test if a tile is sound you should tap it with a wooden mallet. A good tile will sound back with a sharp pitch and a bad one will sound hollow or produce a thud.
If the damage is visible and not a bubble or spall then you should clear the loose pieces and decide if it is worth saving. Holes over about 6 square inches in size may not last over time.
For the patch to hold well in the hole it should be at least half an inch thick.
If you have light surface problems a colorized crack sealer may be a better bet then mortar.
Preparing the Mortar
You will need to have a colorized mason sand that matches the color of the tile. Although stains will help the sand particles will not pickup the stain in the same way the portland cement will.
Color samples should be available at a good local supplier. Sands of this type are used for patching brick and matching grout.
Additives and Accelerators such as calcium chloride should not be used.
A bonding Agent can be used with care.
Making the Repair
If your tile is showing signs of efflorescence from water behind the wall damaging the tile you should address this problem before work begins.
- For Glazed tile cut around the damaged area with a glass cutter to provide a good seam between the repair and good portions of the tile.
- After you have removed the broken pieces of tile you should roughen the surface to provide a good bond. When possible try to backcut the area so it will create a key to lock the mortar in place.
- Clean the area to be repaired with a Wire Brush and then wash with clean water.
- If available blow out any remaining debris with compressed air.
- Fill the repair area with your prepared colored mortar allowing for shrinkage during the cure slightly overfill.
- Once the mortar has set you can finish the surface with a trawl before it cures.
After the repair has cured you can then apply a coating that will help approximate the texture and color of the surrounding tile.
If the tile is unglazed then you can treat the completed patch with micorcrystiline wax.
If the tile is glazed then you will need to choose a paint that can seal the surface along with a clear finish to match the shine of the glaze.
If there are no underlying problems that caused the damage in the first place your patch should last for many years.
It is important to save extra tile when you make an install. If you hire a contractor make sure that any overage is available for you and that they don’t charge you for it and then take it with them.
There are a variety of different specialty tools that will help you with the removal of damaged tile pieces and preparing the area for patching. Diamond tipped saws work well but in most cases a sharp chisels is all that is needed.
Repairing tile will never match the same quality of replacing it and even then a replaced tile will often stick out among others even if it came from the original batch.
Making a repair of this type is only meant to save you the hassle of replacing large sections of tile. And depending on the time and skill you provide a very respectable repair can be had with only a little work.
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