Outdoor tiling: falls, movement joints and the right adhesive
Outdoor tiles in Dubai face 50 °C sun, sudden rain and garden water. Tiles that lift or crack after one summer usually had no movement joints or the wrong adhesive.
- 3–5 mbetween movement joints, plus at edgesPublished standard
- Fallsaway from the house, to drains or the gardenGood practice
- Full coveradhesive under each tile, outdoor-ratedGood practice
- Water testbefore grouting: no poolingGood practice
Good outdoor tiling sits on a sound base laid to falls so water runs off, with waterproofing where there is a room below. It uses an adhesive rated for outdoor use with full cover under each tile, and movement joints across the area, typically every 3 to 5 metres and at every edge and change of surface. Check the falls with water before grouting.
Why check before it is covered. Lifted or hollow outdoor tiles have to come up and be relaid, often with the base under them.
The checklist
0 of 9 checked · 0 issuesEach check shows its basis: Manufacturer Published standard Good practice. Hold points, in coral, are the moments to see the work before it is covered.
The base
Before tiling- The base falls away from the house to a drain or the garden Water against the house walls causes damp inside. Good practice
- Where there is a room below (roof terrace, balcony), it is waterproofed and flood-tested See the waterproofing checklist. Good practice
- The base is solid and cured, with no cracks or loose areas Tiles follow every movement of the base. Good practice
Laying
While tiling- Adhesive rated for outdoor use, with full cover under each tile Voids under outdoor tiles fill with water and heat, and tiles lift. Good practice
- Tiles rated for outdoor use, with slip resistance for wet areas Polished indoor tiles are dangerous wet. Good practice
- Movement joints across the area and at every edge, step and change of surface3–5 m Heat makes tiles expand. Without joints, they push up and crack. Published standard[1]
Before grouting
After laying- Pour water on the area: it runs off, with no pooling The quickest test of the falls. Good practice
- Tap the tiles: no hollow sound Hollow outdoor tiles lift in the first summer. Good practice
- No raised edges or steps between tiles Trip hazard, and water collects behind them. Good practice
All 9 checks, including the hold point. Tick them on site, add notes and photos, and download a PDF to send your contractor. Free with a SoukLocal account.
Sign in freeQuestions to ask your contractor
- Which way does the terrace fall, and to where?
- Is the adhesive rated for outdoor use?
- Where will the movement joints be?
- If there is a room below, when is the flood test?
Questions
Why are my outdoor tiles lifting?
Usually because there are no movement joints, so the tiles push against each other as they heat up, or because there are voids under them. Movement joints are typically placed every 3 to 5 metres and at every edge.
Do outdoor tiles need movement joints?
Yes. Guidance from The Tile Association puts intermediate movement joints at intervals of 3 to 5 metres, depending on the conditions, the tile and the base, plus joints at edges and changes of surface.
Sources
Written from the working method statements of a Dubai design-and-build contractor, then checked against manufacturer data sheets and published guidance. Each check says which. Manufacturer figures are examples from one product or system: follow the data sheet for the product used on your job. This page helps you ask the right questions; it is not a certificate that work is sound.
Related
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