20mm outdoor porcelain tiles are a premium choice for patios, pathways, balconies, and commercial outdoor areas. Their high resistance to stress, frost-proof construction, slip resistance, and resistance to chemicals and atmospheric agents make them exceptionally durable. Many 20mm ranges also colour-match indoor tiles, making seamless indoor–outdoor transitions easy and stylish.
One major advantage of 20mm porcelain is installation versatility. You now have four proven fixing methods for outdoor spaces, meaning there’s a solution for every project and site condition.
1. Installation on Type 1 MOT / GSB (Full-Bed Mortar System)
This method is ideal for domestic patios and landscaped garden areas where a stable base is required.
How It Works
- Install and compact a Type 1 MOT or GSB sub-base.
- Create a full-bed mortar mix using:
- 4 parts sharp sand
- 1 part cement
- SBR additive for improved bonding
- The mortar should be firm—not wet or runny.
- Because porcelain is non-porous, prime the underside of every slab with porcelain priming slurry immediately before laying.
- Lay tiles into the full mortar bed and tap down with a rubber mallet for complete contact.
Tip: Avoid spot bedding. Porcelain requires 100% full coverage to prevent voids or cracking.
2. Conventional Installation on Adhesive (Concrete / Screed Base)
This is the strongest and most permanent method, ideal for areas exposed to heavy loads or high traffic.
How It Works
- Ensure the screed or concrete base is fully cured and perfectly level.
- Apply a high-quality exterior tile adhesive (S1 or S2).
- Use a 10–12mm notched trowel for even coverage.
- Back-butter each tile to ensure complete bonding.
- Prime tile backs with porcelain slurry for improved adhesion.
- Finish with outdoor-grade porcelain grout.
3. Raised Installation on Supports (Pedestal System)
A modern solution perfect for balconies, terraces, and locations requiring hidden drainage or services.
Benefits
- No mortar or adhesive needed.
- Tiles are immediately usable after installation.
- Creates space beneath for drainage, electrical cables, and plumbing.
- Pedestals allow precise height and level adjustment.
How It Works
- Ensure the substrate is stable (e.g., concrete or screed).
- Place pedestals at tile corners (and mid-points if required).
- Adjust pedestal height to achieve perfect levels.
- Lay the tiles directly onto the pedestal heads.
4. Dry Installation on Grass or Gravel
This method is perfect for pathways, stepping stones, and informal garden features.
Grass Installation Steps
- Cut out shallow sections of turf.
- Level the soil and add a thin layer of sand.
- Lay the porcelain slabs and level by tapping gently.
- Leave small gaps to allow grass to grow between the slabs if desired.
Gravel Installation Steps
- Spread a layer of fine gravel.
- Compact and level it.
- Lay the tiles directly onto the surface.
Watch our dry-lay pathway installation video for a step-by-step guide.
Cutting 20mm Porcelain Tiles
20mm porcelain is extremely dense and requires high-quality cutting tools.
Recommended Tools
- Professional bench-top wet saws with a continuous-rim porcelain blade
Important Notes
- Use only a high-grade continuous-rim porcelain diamond blade.
- Clean the blade regularly with a dressing stone.
- Avoid handheld disc cutters due to instability and gyroscopic blade effects.
Do Porcelain Tiles Need Sealing?
No — porcelain tiles do not require sealing. They are UV-resistant, stain-resistant, scratch-resistant, and 100% non-porous.
However, cement-based grout joints are porous and can stain. We recommend sealing all grout joints using a dedicated grout sealer.
Cleaning and Maintenance
Post-Installation Cleaning
Thorough cleaning after grouting is essential. Leftover grout can form a cement film that traps dirt.
- Use a specialist cleaner designed for removing grout residue and construction deposits.
- Always follow the manufacturer’s instructions.
General Ongoing Cleaning
- Regular sweeping.
- Light mopping with warm water.
- Use porcelain-safe cleaners for tougher stains.
For deeper maintenance, see our Pre & Post Maintenance Guide.
Final Thoughts
With four installation methods, strong performance characteristics, easy cleaning, and decades-long durability, 20mm porcelain paving is one of the most reliable outdoor surfacing choices available. Whether you're designing a low-maintenance garden path or a premium roof terrace, there’s an installation system suited to your project.