Which Adhesive & Grout To Use With Outdoor Tiles

Selecting the correct adhesive and grout products is essential for a successful outdoor tile installation but for the uninitiated, choosing the right products for your project can be a minefield. If that sounds like you then don’t worry as we’re here with our comprehensive Outdoor Tiles & Adhesive Guide to answer some common questions relating to which type of adhesive and grout is best deployed in exterior settings.

How Do I Prepare Exterior Walls For Tiling?

If you’re tiling an exterior wall you’ll first want to ensure that the substrate you’re attaching the tiles to is suitable. Brick walls are fine, as are plastered ones, but you must make sure that they’re level and will bear the load of the tiles you’re fixing to them first. Priming is essential where absorption needs to be reduced on surfaces such as render, plywood, plaster, plasterboard and sand:cement screeds.

Anhydrite screeds and gypsum plaster must be sealed before application of any cement based adhesives or failure may occur. You can can prime your substrate using Mapei Primer G, but be aware that primers of this type prevent the adhesive from drying as quickly (and given the British weather, this isn’t ideal as your tiles could quickly get rained on and compromise the setting of the adhesive).

Which Adhesive Should I Use For Exterior Walls?

Whilst tiles fixed to exterior walls are unlikely to be subjected to as much direct water as say those installed in a shower cubicle, you still need to ensure they’re installed using a water resistant adhesive if you want to keep them secured and looking good for years to come. We recommend Mapei Keraquick – it’s suitable for all weather types and is perfect for porcelain tiles (it’s not advisable to install ceramic outdoors).

This particular adhesive can be grouted in just 2 hours and you can use it for an adhesive bed of up to 10mm, making it perfect for 10mm porcelain tiles. Keraquick is available in both white and grey, meaning you can match to the shading of the tiles and prevent the adhesive being visible through tiles. If installing lighter coloured natural stone such as Travertine, always use the lighter coloured adhesive to avoid staining.

Do I Need To Lay A Screed Before Applying Adhesive For Outdoor Floor Tiles?

Ideally, yes. Laying a sturdy screed will provide the best possible foundation on to which your tiles can be fixed and will prevent flexing and slippage. It’s especially important to have a fully cured (we advise leaving a concrete screed to cure for at least 6 weeks prior to applying an adhesive bed) if you’re installing 20cm thick porcelain slab tiles as these heavier, sturdy tiles require a thick bed of around 20mm to ensure the tiles fix properly.

A level, fully cured screed will not only provide a solid base on which to build on but it will also help with the installation’s weather resistance as it’ll provide a foundation from which you can create ‘falls’ – slight gradients in the in adhesive bed that will aide water run-off. For full step-by-step instructions on how to easily fix outdoor tiles to a screed base and info on which products you should use, download our extensive Large Format Porcelain Outdoor Tile Installation Guide

Alternatively, if you don’t want to permanently secure the tiles using adhesive, you can use a ‘suspended system’ such as Adjustable Support Pedestals. You can find out more about these useful products by reading our handy Installing Outdoor Slab Tiles Using Adjustable Support Pedestals guide.

Which Adhesive Should I Use For Exterior Floors?

As mentioned, 18-20mm thick porcelain slab tiles are really rather hefty and require a thicker bed of adhesive to ensure they’re properly fixed. The best product to use for creating such a thing (in our opinion at least) is Mapei Adesilex P4 – it’s a an ideal choice for bonding large format tiles and particularly apt for outdoor slab tiles. Mapei Adesilex P4 offers a full contact, cement-based adhesive in an easily pourable form and is suitable for bonding of all types of medium to large ceramic/porcelain tiles, natural stone (if not sensitive to moisture or subject to surface efflorescence), terracotta, and terrazzo in interiors and exteriors. Best of all though, it can also be used as a levelling compound, meaning you won’t have to shell out on a separate leveller once your screed is down.

When it comes to actually creating your adhesive bed, the general rule is the larger the the adhesive bed, the bigger the trowel required. So for example, you might use an 8mm trowel if you aim to achieve a 4-6mm bed, whereas a 10mm trowel would be the best option to create a 5-7mm bed.

Which Grout Should I Use For Outdoor Wall Tiles?

Now you’ve got your exterior adhesive options sorted you’re most likely thinking about what the best grout to use in your exterior wall tile installation. Mapei Ultracolor Flexible Grout is our recommendation as it is suitable for all weather types and is available in all manner of colours, meaning you can match it to the shade of tiles being installed so as to make grout joints less visually intrusive.

As with interior tile installation, you should only begin to apply grout once your adhesive is fully set (see manufacturers instructions if you’re not sure). It’s also a good idea to ensure you’ve got the right tools for the task in hand before you start – grout float, two buckets, sponge – and to be prepared to clean up as you go along. You can find out more about how to apply grout by watching our handy Top Down Tiling Tips: How To Grout video.

Which Grout Should I Use For Outdoor Floor Tiles?

Mapei Ultracolor really is a hardy beast and can withstand everything the British climate can throw at it, and it’s resistant to organic staining and mould too, making it perfect to use on exterior floors as well as floors. As most exterior floor tiles are quite large, you’ll likely less grout as you’ll use fewer tiles to cover an area, resulting in fewer grout joints. Please bear in mind quantities required before ordering.

Do I Need To Seal The Grout Used In Outdoor Tile Installations?

Whilst sealing grout used in outdoor tile installations is not essential doing so will obviously prolong the life of the grout. We’d recommend using Fila Fugaproof Grout Protector – it’s an odourless, easily applied spray that impregnates grout and gives it excellent stain repellent properties. Simply allow your grout to fully cure, spray a healthy dose of this stuff on it et voila! Your grout is now much easier to clean and will stay looking great for years to come.

So there you have it, a comprehensive guide to outdoor grout and adhesive. Follow our advice and your exterior tiling project should run smoothly and stand the test of time. Don’t forget – if you have completed an outdoor project using Tile Mountain tiles, send in your photos and if we use them on our website you could receive an Amazon voucher up to the value of £20! For further information on how to submit your photos, click here.

To download this guide in a handy PDF format, click the image below:

Download our handy Outdoor Grout & Adhesive Guide now, you rapscallions!

Dean heads up the content team here at Tile Mountain, commissioning, editing and sometimes even writing some of the incredibly useful and entertaining content we bring to you on a regular basis. With a background in consumer journalism and a raft of content marketing experience gained from working with huge brands spanning mobile tech and automotive, right through to professional sports and lifestyle sectors, he knows a thing or two about creating content that people love to engage with. Dean also holds the mantle of being our resident grammar pedant, but when he’s not getting angry about dangling participles he spends his spare time going to gigs, watching his beloved Stoke City FC, and adding to his collection of deadstock adidas trainers.