Yes, you can tile on top of existing tiles.
While technically possible, tiling over old tiles comes with significant considerations and potential downsides. The provided information highlights the core issue: "why would you?" The primary concerns revolve around the integrity of the original layer and the added bulk of the new tiles.
Why Tiling Over Old Tiles is Possible (But Often Not Recommended)
Putting new tiles directly onto existing ones is sometimes considered a shortcut to avoid the mess and labor of removing the old tiling. However, the ease of installation is often overshadowed by the potential problems that can arise down the line.
The reference points out two critical drawbacks:
- Inheriting Existing Problems: If the original tiles have issues such as being loose, cracked, or poorly adhered to the substrate, tiling on top of old tiles means that any problems with the originals, such as becoming loose, will still be an issue with the new layer. The new tiles will only be as stable as the old layer underneath.
- Increased Thickness: Adding a new layer of tiles plus adhesive significantly increases the floor or wall thickness. This extra depth can also make it more difficult to accurately install fixtures and fittings, such as toilets, sinks, shower valves, or door frames, requiring adjustments or extensions that add complexity and cost.
Potential Issues Summarized
Here's a quick look at the main points:
- Pro: Saves time and effort on removal.
- Cons:
- Weak Foundation: Any instability or damage in the underlying tiles is transferred to the new surface.
- Bulk: Adds thickness, affecting adjacent surfaces, transitions, and fixture placement.
- Weight: Adds considerable weight, which could be a structural concern on upper floors.
- Preparation: The old tiles must be perfectly clean, flat, and sound, which isn't always easy to guarantee without removal.
It is generally considered best practice to remove old tiles, prepare the substrate properly, and then install the new tiles directly onto a clean, stable surface. This approach ensures a durable and problem-free installation.
