Reusing old tiles is a great way to save money and reduce waste — but only if you can get them properly clean. The good news is that with the right approach, most tiles can be cleaned up well enough to relay, though the effort involved depends heavily on what type of adhesive was used and how long it's been there.
Identify the Type of Adhesive First
Before you reach for a chisel, it pays to know what you're dealing with. The two most common tile adhesives in NZ homes are:
- Cement-based adhesive (thin-set mortar): Grey or white, hard, and chalky when dry. Very common in wet areas and floor tiles. This is the trickier one to remove.
- Mastic or acrylic adhesive: Usually tan or off-white, slightly flexible when cured. More common in older wall tile installations. Generally easier to remove.
If your home was built before the 1980s, there's a chance the adhesive (or the tiles themselves) could contain asbestos. Do not sand, grind, or aggressively chip old adhesive without checking first. If you're unsure, have a sample tested by a licensed asbestos assessor before proceeding. WorkSafe NZ has guidance on managing asbestos in DIY situations.
Tools and Materials You'll Need
- Stiff putty knife or wide scraper
- Rubber or wooden mallet
- Cold chisel (for stubborn cement-based adhesive)
- Angle grinder with a diamond cup wheel (for large batches — use with care)
- Bucket of warm water and a sponge
- White vinegar or a proprietary adhesive remover
- Safety glasses, gloves, and a dust mask (P2 rated minimum)
- Flat, stable work surface
Step-by-Step: Removing Cement-Based Adhesive
This is the most common scenario for floor tiles and wet-area wall tiles.
- Lay the tile face-down on a flat, padded surface (an old towel works well) to avoid scratching the face.
- Soak the back with warm water for 10–15 minutes. This can soften the bond slightly and reduce dust.
- Use a cold chisel and mallet at a low angle to chip away the bulk of the adhesive. Work in short, controlled strikes — tiles can crack if you're too aggressive.
- Scrape off the remainder with a stiff putty knife or scraper, working at a shallow angle.
- For stubborn residue, apply a cement dissolver or tile adhesive remover — products containing phosphoric or hydrochloric acid can be effective. Always follow the manufacturer's instructions, wear gloves and eye protection, and work in a well-ventilated area.
- Rinse thoroughly with clean water and allow tiles to dry completely before assessing the back surface.
Using an Angle Grinder
For a large batch of tiles, an angle grinder fitted with a diamond cup wheel speeds things up considerably. However, this creates significant dust — always wear a P2 dust mask, eye protection, and hearing protection. Work outdoors or in a very well-ventilated space. This method is not recommended if asbestos contamination is a possibility.
Step-by-Step: Removing Mastic or Acrylic Adhesive
This type is generally more forgiving.
- Warm the adhesive with a heat gun on a low setting — this softens mastic and makes it much easier to peel away. Keep the heat gun moving to avoid cracking the tile.
- Peel or scrape the softened adhesive off with a putty knife.
- Clean residue with a cloth dampened in white vinegar or a citrus-based adhesive remover. Avoid harsh solvents on glazed tiles as they can dull the surface.
- Wash and rinse the tile back and face, then dry.
Checking Tiles Are Suitable for Reuse
Once clean, inspect each tile carefully:
| Check | What to look for |
|---|---|
| Cracks | Hold the tile up to light; hairline cracks may not be obvious flat on |
| Chips | Especially on edges and corners — these affect both appearance and grout lines |
| Back surface | Should be reasonably flat; deep pitting can affect adhesion when relaying |
| Glaze condition | Scratches or etching on the face may be cosmetically unacceptable |
Tiles with significantly uneven backs may need a thicker bed of adhesive when relaying — discuss this with your tiler if you're unsure.
Relaying Cleaned Tiles
When you're ready to relay, use a quality tile adhesive suited to the substrate and location. For wet areas like bathrooms and kitchens, make sure the adhesive and grout meet the requirements of the relevant NZ Building Code clauses covering internal moisture and wet areas. Products from Ardex and Mapei are widely used by NZ tilers and are available at trade suppliers and Bunnings or Mitre 10.
Always check with your local council whether your tiling project requires a building consent — most like-for-like tile replacements are exempt under Schedule 1 of the Building Act, but confirm this before starting, particularly if waterproofing membranes are involved.
When to Call a Professional
Consider bringing in a qualified tiler if:
- You have a large volume of tiles to clean and relay
- The substrate (floor or wall) has been damaged during tile removal
- The area involves waterproofing (shower liners, wet rooms) — incorrect waterproofing can lead to serious moisture damage and may not comply with the Building Code
- You suspect asbestos in the old adhesive
- The tiles are large-format, natural stone, or otherwise high-value
A skilled tiler will also be able to advise whether your salvaged tiles are genuinely worth the effort to reuse. You can find qualified local tilers on tradedirectory.co.nz.
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