How to lay porcelain tile outdoor

How to install outdoor tiles successfully is dependent on a few different factors, the key ones being the tiles you use, the substrate you lay them on, and the essentials used to fit them. In this article we take you through how to lay porcelain tiles outside and recommend the right fitting products to be used with our outdoor suitable tiles.

So, what tiles can I use outside? We’ve answered that very question in a dedicated tile guide. But to make choosing simple, just shop our designated outdoor tiles section on our website.

How thick should outdoor tiles be? This is largely dependent on the substrate, the tile, and the use of the space however we’d always recommend a 1cm thick tile for outdoors made from porcelain that is frost proof and preferably slip resistant.

If you don’t have or want to invest in a concrete screed, then take a look at specialist outdoor tiles like our Everscape range. The 2cm depth means you can lay them on grass, gravel, pedestals, or cement providing excellent versatility.

The next step in how to lay outdoor tiles lies in the substrate and its preparation.

It’s recommended that the substrate for exterior tiles is a concrete or cement sand screed with a minimum thickness of 50mm. You must ensure that the substrate is able to support the chosen finish and any static or dynamic loads applied (this could be a garden shed or a driveway for example).

There must be falls in the sub-floor which should be between 1:35 and 1:80 with the water encouraged away from the building. To convert gradient into a fall of cm, first convert the gradient ratio into a number

1/35 = 0.0285

1/80 = 0.0125

Multiply the gradient number by the distance, this will equal the fall

0.0125 x 4 metres = 0.05 metres

0.0285 x 4 metres = 0.114 metres

This example shows that if the fall away from the building of a 4m substrate is between 5-11.4cm it will provide adequate water run-off.

Check if there is a Damp Proof Membrane incorporated within the existing substrate, if this is not the case then a BAL DPM should be applied in a two-coat application. The second coat should be blended with a suitable aggregate to provide a mechanical key prior to applying the screed or tiling.

For direct fixing, the floor should have a surface tolerance of SR1, for example when a 2m long straightedge is placed on any part of the floor, the gap between the straight edge should not exceed 3mm. For small repairs in limited areas of the screed, use BAL PTB Fibre Plus, applied to a maximum of 25mm as a separate step.

Do not carry out this work unless the temperature is above 5°^C and before tiling, the screen should be fully cured.

For newly laid concrete; allow concrete to dry for a minimum of 6 weeks (a longer period will be required in poor drying conditions and colder temperatures).

For concrete sub-floors without a fall, create a fall with a cement sand screed.

Unbonded cement sand screeds should be laid to falls i.e. minimum 50mm up to a maximum of 70mm. Bonded cement sand screed may be considered, but only if there is a DPM incorporated within the concrete substrate.

BAL Quickset Cement, when used as a replacement for Portland cement, will allow tiling to commence on an unbonded cement sand screed after a minimum of 48hrs. For bonded screeds a minimum of 4 hours.

For a new cement sand screed; cover the screed and allow to cure for 7 days then uncover for a further 14 days of continual air drying (a longer period will be required in poor drying conditions and colder temperatures).

Unbonded cement sand screeds should be laid to falls i.e. minimum 50mm up to a maximum of 70mm. A bonded cement sand screed may be considered, but only if there is a DPM incorporated with the concrete substrate.

BAL Quickset Cement, when used as a replacement for Portland cement, will allow tiling to commence on an unbonded cement sand screed after a minimum of 48hrs. For bonded screeds a minimum of 4 hours.

If you’ve got an existing outdoor patio that you wish to replace with new tiles, the quickest way of removing the tiles is to hire a cordless rotary chipping hammer. Depending on how the old patio tiles were laid, it should be relatively easy to pop each tile off by using a ¾-inch flat chipping chisel.

The key is to go slow and carefully and ensure you wear safety goggles and thick gloves.

Whether you’re removing porcelain, clay patio tiles, quarry tiles or terracotta slabs from a concrete patio (aka a concrete screed), you will also need to remove any leftover thinset or adhesive residue from the substrate. The fastest way to remove it is with a wide chisel, tapping towards the product.

Before installing your new tiles, ensure the area is completely smooth and all dust and debris has been cleared.

Ensure the sub-floor is dry and clean with all efflorescence, laitance, dirt and any other barriers removed using suitable mechanical methods.

Apply the chosen adhesive to the dry base in areas up to 1m², for porous bases apply a skim coat of adhesive before combing a tiling layer.

For larger tiles, back butter the reverse side of the tile before place onto the adhesive bed, firmly press the tile into position with a twisting and sliding action.

What grout to use outside? Pretty much any grout, however you need to think of the long term quality of the grout. Something specifically formulated to work outdoors will be better for the job,

Ultra Tilefix Grout and Azpects Easy Joint Grout are designed to work with our outdoor specific tile ranges Everscape and Spaces. For other tiles that are suitable for outdoors, BAL Micromax3 will work well.

Before grouting all adhesive must be fully dried. Thicker beds of adhesives and lower temperatures will increase drying times. Ensure your grouts lines are a minimum of 3mm.

Place some grout on the tiles, hold the grout float at a 45° angle and apply the grout ensuring all the joints are filled. Once all the joints between the tiles are grouted (working in small areas), leave to dry for approx. 10-15 minutes then wipe the tile surface with a damp sponge, but don’t put too much pressure on the grout joints and don’t over wash. The face of the tiles may require a second wash down to get rid of the grout residue.

After approx. another 60 minutes, when the grout has hardened a little use a grout profiler at a 45° angle and press down on the grout joints and drag across to take off any excess grout and smooth it off. Using a clean cloth polish down the tiles until completely clean.

Movement joints will be required as per British Standard BS 5385-3. Perimeter joints should be installed and intermediate joints should be incorporated at 3m intervals. The joints should be a minimum of 6mm cross section and filled with BAL Micromax2 Sealant.

If a tile is suitable for outdoor use then it shouldn't need sealing to protect it from the elements. However, if you're using natural stone which hasn't been specifically manufactured for outdoor use, it will need sealing to protect it from water marks and staining.

The type of sealant required will be dependent on the tile used, for further advice please ask our in store specialists.