Can You Tile Over Existing Tiles
Yes, you can tile over existing tiles, provided the tiles underneath are firmly stuck down, flat, clean and sound. It is a common and perfectly legitimate way to update a wall without the mess, dust and potential damage of hacking the old tiles off first. The key word is sound. Tiling over a solid, well-bonded surface works well, while tiling over loose or hollow tiles simply means your new tiles come away when the old ones do.
Before you commit, there are a few things to check, because tiling over tiles is not always the right choice. The condition of the existing tiles, the weight the wall can carry, and the extra thickness the new layer adds all decide whether it is a good idea or a false economy. Our team has been decorating across Kent for over 30 years, and the tiling jobs that go wrong are almost always the ones where nobody checked what was underneath before starting.
When You Can Tile Over Existing Tiles
The existing tiles have to meet a few conditions for tiling over them to work.
They must be firmly bonded to the wall, which you check by tapping across them and listening. A solid, sharp sound means the tile is stuck fast, while a hollow or drummy sound means it has come away from the wall behind and is no longer reliable. We’ve found the tap test is the single most useful thing you can do before deciding, because a wall that sounds solid all over is a good candidate, while one with hollow patches is telling you to think again. The surface also needs to be flat and even, with no lipping between tiles, and it must be clean and free of grease, soap scum and mould.
When You Should Not
There are situations where tiling over tiles is the wrong call, and forcing it only stores up problems.
If more than the odd tile sounds hollow or is cracked, or if any are actively loose, the existing surface is not stable enough to build on. If there is any sign of damp behind the tiles, that needs solving first, because sealing it in under another layer makes it worse. And weight is a genuine consideration, particularly on plasterboard or stud walls, because tiles and adhesive are heavy and there are limits to how much a plasterboard wall can safely carry. Adding a second layer of tiles on top of the first can take the wall past that limit, so on anything other than a solid masonry wall the weight has to be thought about rather than assumed.
The Thickness It Adds
Tiling over tiles raises the finished surface, and that has knock-on effects worth planning for before you start.
From working with clients, the thickness the new layer adds is the part most people overlook, and it is usually the sockets and the window reveals that catch them out rather than the tiling itself. The extra layer pushes the wall out by the depth of the tile and adhesive, which affects where sockets and switches sit, how window reveals and sills look, and how the tiles meet worktops, baths and trims. Sockets may need packing out or refitting, and edges and trims need to account for the new depth. None of this is a reason not to tile over tiles, but it is a reason to plan the edges and junctions properly rather than discovering the problem partway through.
Preparing The Existing Tiles
Because a glazed tile is smooth and non-porous, the surface has to be prepared so the new adhesive can grip it.
That means cleaning and degreasing thoroughly, then keying the glaze by sanding or abrading it, or using a proper priming or bonding product designed to let tile adhesive stick to an existing glazed surface. Any gaps, cracks or missing tiles should be filled and levelled first so you are building on a flat, continuous base. Cutting tiles to fit creates fine dust, and cutting ceramic and porcelain in particular releases silica dust that is harmful to breathe, so it is worth following the guidance on controlling construction dust and keeping the dust down with water or extraction rather than cutting dry.
In our experience, tiling over sound, firmly bonded tiles works better than stripping them off first because removing old wall tiles very often pulls chunks of plaster off with them, leaving you with a re-plastering job and a drying-out period before you can even begin tiling, whereas tiling over a solid existing surface avoids that damage completely. The exception is when the existing tiles are not sound, in which case stripping back and making good is the only reliable route, however much more work it is.
What About Floor Tiles
The same principle applies to floors, with a couple of extra considerations. The existing floor tiles must be solidly bonded and the substrate beneath sound, and the added height has to work with doors that open over the floor and with the thresholds into other rooms. On a floor, any movement or hollowness in the existing tiles is even more likely to crack the new ones, so the base needs to be genuinely solid.
Getting It Right
Tiling over existing tiles can save a great deal of time and mess when the surface underneath is sound, flat and clean, and it is often the sensible choice. When the existing tiles are loose, damp or on a wall that cannot take the weight, removing them first is the more reliable path even though it is more work. The judgement call is really about what is underneath, and it is worth getting that right before any new tile goes up.
If you would like the job assessed and done properly, our team at A-Z Decorators offers tiling as part of our interior decorating work throughout Kent, with over 30 years behind us and a warranty on completed work. You can see finished work in our gallery, or get in touch for a free, no obligation quotation.