20mm outdoor porcelain paving: a buying guide
A new patio is one of the few home improvements you get to enjoy from a deckchair. Porcelain paving is a strong choice for it, and this guide covers the decisions that matter: thickness, colour, slab size, how many boxes, and what to agree with your installer before the first slab goes down.
Why 20mm porcelain for outside?
Most of our indoor porcelain tiles are 9 to 10.5mm thick. Our outdoor slabs are 20mm, roughly double, so they are made for the garden from the start rather than being an indoor tile taken outside.
Porcelain is dense and absorbs very little water, and every outdoor slab we stock is listed as frost resistant. The face is matt, with a stone, concrete or terrazzo look. Rectified edges help your installer keep the lines straight and the joints neat.
Choosing a colour and effect
Pick the paving against what it will sit beside, the house, the fence and the planting, rather than on its own.
Light colours
Whites and pearls bounce light around and make a small or shaded garden feel larger. Ground Arena is a white stone effect at 60 x 90 cm, and Materia Perla a pale pearl concrete effect in a big 76 x 76 cm square.
Mid grey
Mid grey goes with most houses and furniture, which makes it a good fit for a family patio. Hazel Gris is a plain mid grey concrete effect, and Nord Stone Ice a lighter grey with soft stone veining.
Dark greys and black
Charcoal gives a modern, designed look and makes every green look richer. Milky Way Graphite, Volcanic Grey and Meribel Graphite cover three sizes in this family.
Something with pattern
If plain paving feels too quiet, Urbex Marengo is a dark terrazzo effect flecked with lighter chips, and Imperial Concrete a warm speckled brown that sits well with red brick.
Screens only get you so far. You can view any of these slabs at our Uxbridge showroom, open seven days a week, and it pays to bring a brick or a piece of fence to set beside them.
Which size?
Our outdoor range runs in three main sizes, and the choice changes the look more than people expect.
- 60 x 60 cm (600 x 600mm): the classic square. A tidy grid that suits smaller patios and paths.
- 60 x 90 cm (900 x 600mm): a rectangle for a straight grid or a staggered bond. It gives the patio a gentle direction with fewer joints than a square.
- 60 x 120 cm (1200 x 600mm): the long plank. Fewer joints again, and running the long side down the garden can make it feel longer. Your installer can advise on the layout.
We also carry 76 x 76 cm (760 x 760mm) squares for anyone who wants an oversized grid.
Working out how many boxes
Multiply the length and width of the area in metres to get the square metres, divide by the square metres in a box, and round up. Add around 10 per cent for cuts and spares, more for curves and lots of edges.
Boxes vary by product, so use the figure on the product page. Real examples from our range, for a 20 m² patio with 10 per cent added:
| Slab | Per box | Boxes |
|---|---|---|
| Meribel Graphite 60 x 60 cm | 2 slabs, 0.72 m² | 31 |
| Milky Way Graphite 60 x 90 cm | 2 slabs, 1.08 m² | 21 |
| Nord Stone Ice 60 x 90 cm | 1 slab, 0.54 m² | 41 |
| Volcanic Grey 60 x 120 cm | 1 slab, 0.72 m² | 31 |
Every product page has a box calculator, and if you send us your measurements we'll check them.
What to agree with your installer
20mm porcelain can be laid in more than one way, and the right one depends on your garden.
The base
Ask what the slabs will be bedded on. A full mortar bed over a compacted sub-base is the usual method for a ground-level patio; raised terraces and balconies are often laid on adjustable pedestals, one of the advantages of a flat, rectified slab. Your installer should also set a slight fall so rain runs away from the house.
Priming and joints
Porcelain takes in so little water that installers normally prime the back of each slab before laying; ask how they plan to do this. Rectified edges allow neat, narrow joints, though outdoor joints are usually a touch wider than indoors to allow for movement. Agree the joint width and the jointing compound, and see its colour next to your slab.
Steps, edges and slopes
If the design includes steps, a ramp or a raised edge, tell us and your installer early, as the cuts and step edges need planning before the paving is ordered.
Slip rating
All our outdoor porcelain is rated R11. The R scale comes from a standard ramp test, running from R9 to R13, and R11 is a common specification for outdoor floors. It is a rating of the surface rather than a promise, so for steps and sloping paths, ask us which slab and layout suit your garden.
See it before you buy
Browse the whole range at outdoor tiles, or visit our Uxbridge showroom, an easy drive from Hayes, Slough and Harrow and open seven days a week, where you can see any slab in person.
Frequently asked questions
What does the "2" in 60x90x2 mean?
The thickness: 2 cm, or 20mm, roughly twice an indoor tile.
Can 20mm porcelain go on a balcony or roof terrace?
Often yes, on pedestals. Your installer or a structural engineer should confirm what your balcony can take.
How much extra should I order?
Around 10 per cent over the measured area, a little more for curves and corners. Keep a box back after the job so a future repair matches.