Blown tiles refer to tiles that lift, bulge, or “pop up” from the floor or wall surface. This usually happens when the bond between the tile and the substrate fails, causing the tile to detach or crack. It’s common in hot, humid tropical climates due to environmental factors.

Causes of Blown Tiles

Here are the main reasons tiles may “blow”:

a) Moisture and Humidity

Moisture seeps beneath tiles, often from leaks, ground dampness, or insufficient waterproofing.
Over time, moisture weakens the adhesive and causes tiles to lift.

b) Thermal Expansion

In the tropics, temperature swings cause tiles and substrates to expand and contract.
If expansion joints aren’t installed, pressure builds and tiles can lift or crack.

c) Poor Installation

Using the wrong adhesive or not applying enough.
Tiles laid without leaving adequate spacing.
Skipping proper substrate preparation.

d) Substrate Movement

Concrete shifting or settling creates uneven pressure under tiles.

e) Efflorescence or Salt Crystals

In coastal or humid areas, salt deposits can build up under the tiles, causing lifting.

How to Prevent Blown Tiles

a) Use the Right Adhesive and Grout

Choose flexible, high-quality adhesives like polymer-modified thinset, designed for tropical or exterior use.
Use water-resistant grout with additives to resist moisture and salt.

b) Proper Substrate Preparation

Ensure the surface is clean, dry, and levelled before tiling.
Apply a primer if needed to enhance bonding.

c) Install Expansion Joints

Leave adequate space around room edges and between large sections of tile.
Use silicone or flexible sealant in these joints to allow for expansion and contraction.

d) Ensure Good Drainage

Avoid water pooling under tiles, especially in patios, pool decks, and bathrooms.
Use a waterproof membrane in wet areas.

e) Control Temperature and Humidity

For outdoor installations, choose light-coloured tiles that stay cooler.
For interiors, maintain good ventilation to reduce moisture buildup.

f) Regular Maintenance

Check for early signs of hollow sounds, cracks, or slight lifting.
Regrout or reseal tiles regularly in high-moisture areas.

Repairing Blown Tiles

If tiles have already blown:

Remove affected tiles carefully.
Clean and level the substrate thoroughly.
Apply a flexible adhesive and re-lay the tiles, ensuring proper spacing and bonding.
Consider replacing broken tiles with spares to match the original design.

TIP: When tiling your floors always keep extra tiles in case you need to replace cracked or broken tiles. In many cases the Tile supplier will NOT continue to carry the exact same times from year to year, so replacements are hard to find.