One of the most frequently asked questions when it comes to tiling is - "Can you tile over existing tiles?". There are two sides to this question. Technically - it can be done but in practice it is avoided. This method of tiling depends on the condition of tiles which are already installed. Since these tiles are already worn-out and damaged by humidity or have uneven areas, the tiling over existing tiles is not advisable. There are other factors such as weight and moist absorption which can also make you re-think your plan.

Before You Start:

First - inspect the current state of the tiles which you already have. This is important as they are going to be the foundation of your tiling. Your tiling needs to be well-sealed and bond with the base. If your current tiles are well-laid and there are no cavities between them and the base flooring you can lay the new tiles. To check for cavities you can just tap and for a search for hollow sounds. These cavities are usually caused by the lack of adhesive between the tiles and the sub-flooring but can also be a result of an earthquake or a construction site nearby.

Also consider:

If the base is plasterboard, consider the additional weight of the two layers of tiles. Plasterboard has a maximum weight limit per square centimeter and exceeding this limit may cause structural damage.

Not every type of adhesive is right for tiling over tiles. Since a tile is made to endure humidity and to absorb the least amount of water possible most adhesives won't work.

When laying the tiles, bear in mind that your floor will be raised between one and three centimeters. This means that any door frames, kitchen appliances, and furniture and bathroom storage units should be fitted accordingly. You can use a door threshold to level or transition between two types of flooring. If you have to tile only half of the room it is more aesthetically pleasing to remove the old tiles first.

Before You Start Tiling Over Tiles

If you have put these requirements into consideration and there are no hollow sounds you can proceed to lay the tiles. Before you do that, you should clean spotless your existing ceramic tiles. This step is very necessary and often overlooked. In fact, it is done not because it will look good but because any grease or dust will make it harder for the tile adhesive to bond. So make sure you degrease everything and the grout is perfect too.

Removing The Tiles

If your existing tiles don't meet the requirements and it has cavities or uneven parts, or are too heavy, then removing them is the better option. Depending on the sub-flooring there are different methods of doing so. Generally, the easiest way is to remove the backer board, if one is used. Of course, removing the tiles is more expensive, that's why many people decide to choose this method in the first place.

In Conclusion

Can you tile over tiles? Yes.

Should You? Most of the times - no.

When can you do it?