Domakihub Tile Over Existing Tiles Without a Full Strip-Out
Save days of demolition by laying new tiles directly onto sound old ones — if you know the right checks first.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 5 min read
Ripping out old tiles is dusty, noisy, and can take a whole weekend in a Greek holiday villa or Athens apartment. Tiling over existing tiles is a legitimate alternative — but only when the substrate passes a few non-negotiable tests. The video above walks through the practical process; this article gives you the full checklist, step-by-step method, and the warning signs that mean you should call a licensed tiler instead.
When Tiling Over Is Acceptable
Overlay tiling is permitted under most Greek building codes for internal floors and walls — it does not require a building permit as long as you are not altering the structure, the damp-proof course, or load-bearing elements. For hotel rooms and short-term rental kitchens or bathrooms, overlay tiling is a practical way to refresh surfaces between seasons with minimal downtime.
The ceiling height in the room must accommodate the extra tile thickness (typically 10–14 mm with adhesive). In bathrooms with waterproofing membranes already correctly installed behind the old tiles, overlaying is acceptable; if you suspect failed waterproofing — rising damp, dark staining, or hollow tiles near shower trays — the old tiles must come off and a licensed waterproofing contractor must re-treat the substrate before any new tiling starts.
When You Must Strip Back Instead
Never overlay if: more than 20 % of the existing tiles are hollow when you tap them (a coin-tap test reveals a dull thud instead of a solid ring); the existing adhesive layer is unstable or the tiles are ceramic over a timber subfloor with significant flex; the room has a history of damp ingress; or floor thresholds and door clearances cannot accept the extra height.
Any work involving structural walls, load-bearing slabs, underfloor heating re-commissioning, or drainage re-routing must be carried out by a licensed civil engineer or registered contractor (diploma-level technikós) in Greece. Permit requirements also apply to balconies and exterior terraces.
How to Tile Over Existing Tiles: 5 Steps
- 1
Inspect and prepare the existing surface
Tap every tile systematically with a small mallet or coin. Mark hollow tiles with a pencil; if more than one in five sounds hollow, do a full strip-out. Re-bond any isolated loose tiles with flexible tile adhesive and allow 24 hours to cure. Grind down any lips or high edges with an angle grinder fitted with a diamond cup wheel so the entire surface is flat within 3 mm over a 2 m straightedge. Clean thoroughly with a degreaser to remove soap scum, wax, or grease — adhesion depends on it.
- 2
Apply a bonding primer or key coat
Standard cement-based adhesives bond poorly to glazed ceramic. Apply a specialist bonding primer (epoxy-based or an acrylic bonding slurry such as those sold under brands like Mapei Eco Prim Grip, Ardex P 51, or equivalent products available at Greek building merchants) across the entire tiled surface with a roller. Allow to dry to a tacky state — typically 30–60 minutes depending on temperature and humidity. In summer on a Greek island, work in the cooler morning hours as high heat accelerates drying and can cause the primer to skin over before you tile.
- 3
Set out your tile layout
Find the centre of the floor or wall and snap chalk lines to create four equal quadrants. Dry-lay a row of new tiles with spacers from the centre outward to confirm the cut sizes at the perimeter — avoid thin slivers of less than half a tile width at edges, especially around doorways and shower trays. Account for the new grout joints, which may not align with the joints of the existing tiles beneath; deliberate offset layouts (a brick-bond or 45-degree diagonal) help disguise this and prevent weak stacked-joint lines.
- 4
Spread adhesive and bed the new tiles
Use a flexible, polymer-modified tile adhesive rated for tile-on-tile applications (check the data sheet for 'tile-on-tile' suitability). Apply with a notched trowel — typically a 6 mm V-notch for wall tiles up to 300 x 300 mm, or a 10–12 mm square-notch for larger format floor tiles. Back-butter each new tile as well for full coverage, which is essential over non-porous glazed surfaces. Press each tile firmly, twist slightly, and check with a level. Work in manageable sections of about 1 m² at a time; do not let the adhesive skin over before placing tiles.
- 5
Grout, seal, and finish edges
Allow the adhesive to cure fully — a minimum of 24 hours for walls, 48 hours for floors before foot traffic, and always follow the manufacturer's data sheet. Remove spacers and apply grout with a rubber float, working diagonally across joints. Sponge off excess grout before it hazes. At movement joints (corners, perimeter edges, where new tile meets a different surface), do not use grout — fill these with a flexible silicone sealant in a matching colour. Silicone joints are mandatory at internal corners in wet areas; skipping them is the single most common cause of tile cracking and grout failure in bathrooms.
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FAQ
- Will the floor level difference cause a trip hazard at doorways?
- It can. Adding a tile-on-tile layer typically raises the floor by 10–14 mm. At doorways you will need a threshold or transition strip to bridge the height change neatly. If the new floor level would sit higher than an existing shower tray lip or drain surround, the drainage fittings must be raised or the tray replaced — consult a licensed plumber before proceeding.
- Can I tile over tiles in a wet shower enclosure?
- Yes, provided the existing waterproofing layer behind the original tiles is intact and there is no evidence of water ingress or efflorescence. Use a flexible, waterproof tile adhesive and apply flexible silicone at all internal corners and transitions. If you have any doubt about the waterproofing, strip back to the substrate, apply a new tanking membrane (applied waterproofing), and then re-tile — cutting corners on wet-area waterproofing leads to structural damp damage that costs far more to repair later.
- What size new tiles work best over existing tiles?
- Smaller-format tiles (up to 300 x 300 mm) are more forgiving because they bridge minor undulations in the old surface more easily. Large-format tiles (600 mm and above) require a very flat substrate — any deviation greater than 3 mm under a 2 m straightedge will need to be corrected with a self-levelling compound compatible with tile-on-tile applications before laying. Heavy large-format stone or porcelain slabs on a second adhesive layer can also add significant dead load; on upper floors of older buildings, consult a structural engineer if in doubt.