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Tiles for Central Otago frost: what to look for
Winter nights in Central Otago regularly drop below zero. Outside, a tile has to cope with water getting in and freezing — and with people walking on it when it is wet.
Why tiles crack in frost
Water that soaks into a tile, or sits in gaps under it, expands when it freezes. Night after night, that pressure can crack the tile or lift the surface off. Low-absorption tiles and a solid, well-drained bed are the two defences.
What to check on the tile
- Water absorption of 0.5% or less (porcelain).
- Frost resistance tested to ISO 10545-12 — it is listed on the technical sheet when the tile has passed.
- A slip rating for outdoor use, such as R11 (DIN 51130) or P4–P5 (AS 4586). Wet, sloping or shaded areas need the higher ratings.
- Thickness: 20 mm outdoor pavers can also be laid on gravel or pedestals in some situations; standard tiles need a solid bed.
What matters in the installation
A fall so water runs off instead of sitting on the surface, an adhesive made for outdoor use and temperature changes, full adhesive coverage with no hollow spots, and movement joints where the design calls for them.
Frost also affects the work itself: adhesives and grout need to cure above the temperature on their bag, so check the forecast before laying outside in winter.