A Guide to Lay Porcelain Tiles Outside

Image: tile patio.

Picture of an elegant tile patio.  George Gutenberg/Getty Images

How to Laying Tile Outside

Instructions for Building Tile Patios

Laying tile outdoors to build a new patio may seem like a daunting task. Indeed, it’s a project that entails many steps, and you’ll be challenged to make the right decisions along the way. Make the wrong decision (e.g., in selecting product X over product Y, when shopping) at any juncture, and the whole project could be jeopardized! That’s why Joe Norton, mason and tile setter, breaks the project down into nine easily-understandable steps. Learn how to lay tile outside a step at a time — and receive expert help on all those tricky decisions.

How to Prepare Concrete Slabs for Laying Tile Outside 

Your first task in laying tile outdoors to build a patio will be to provide a solid base. The following article deals with preparing an existing concrete base, but it also links to a resource devoted to pouring a new concrete slab.

Choosing the Right Flooring Product 

Novices will have to acquaint themselves with the pros and cons of the different materials available for this patio project. Your success in laying tile outside depends on, among other things, selecting a flooring material that will stand up to the elements. Consult the following resource for advice on this critical decision:

Selecting and Mixing Adhesive for Laying Tile Outside

Similarly, you’ll need to buy a proper adhesive, with which you can lay tile outside and have it hold tight! Consult the following resource for help with this aspect of the patio project, including how to mix the adhesive and how much of it you’ll need:

Laying Tile Begins With the Layout

OK, you have a solid base in place, plus the materials needed to build on that base. What now? Well, I don’t know about you, but I wouldn’t trust myself to just start laying tile “by eye,” hoping that the placement of each square ends up being right. In the following resource, Joe discusses how to create a grid that will serve as your visual guide in this project:

Mark Expansion Joints As Part of Your Layout

While many joints in your new patio will be grouted (see below), others will be treated differently: namely, as “expansion joints.” Expansion joints will be marked as such during the layout (see above). In the following resource, Joe explains the concept behind expansion joints and instructs us on how to handle them:

How to Lay Tile Outside

Now the process of laying tile, proper begins. If you’ve followed all the steps above, this step should go rather smoothly. Here’s how to set your flooring onto the concrete slab, using the adhesive discussed earlier:

Making the Cut: It’s Easier Than You Think

The aspect of this patio project that probably troubles novices the most is making cuts. Power saws can be scary for those not used to handling such equipment, and I would be the last one to make light of someone’s healthy fear of dangerous tools: Garden safety is no joke. But I think you’ll be pleasantly surprised by what Joe has to say about using a wet saw in this article:

Making the Cut: It’s Easier Than You Think

Penultimate Step: Grouting

You’re almost home now! But first you have to apply the grout (and fill in those expansion joints I mentioned earlier). How to grout between the cracks is the subject of this resource, which takes you from buying to buffing:

Last Step: Using a Grout Sealer

We’ve come a long way since preparing that concrete slab! Your flooring is now bonded to the slab (using the adhesive), and the cracks between have been filled in. But after you apply the grout, you must use a grout sealer on it. Learn why this is necessary — along with how to choose a grout sealer — in the following article:

How to Use Outdoor Tile Sealants

Products to Use When Tiling Outside

Grouting ceramic tiles.

yunava1 / Getty Images

The final step in tiling your outdoor patio is to seal the tile grout. There are many sealers (or “sealants”) on the market used to seal tile grout, protecting it from stains and prohibiting moisture absorption, which can be a problem in freezing conditions.

Most home improvement stores carry a variety of tile grout sealers. The most common are penetrating sealers and topical sealers. Topical sealers only seal the top layer of the tile grout. They’re very effective at keeping tile grout clean, but only until foot traffic works the sealer off the surface. Penetrating sealer seals all of the tile grout. While a bit more expensive, it will keep your tile grout looking good longer.

How to Grout Tile

List of Supplies, Instructions

Outdoor patio with plants

penguenstok/Getty Images

Grouting tile is one of the final and most important steps of a successful outdoor patio installation. Grout is a cement product used to fill the joints between tiles. Let’s begin with a list of the tools and materials that you will need for the task:

Supplies List

    • Electric drill
    • Paint mixer/paddle
    • 5 gallon bucket and clean water
    • Tile sponge
    • Rags
    • Grout and grout float

There are three common types of grout from which to choose:

    • Sanded grout is a Portland cement product mixed with fine sand. It is generally used to grout tile when the joints are larger than 1/8 inch thick.
    • Unsanded grout is also a Portland cement product, but, since it lacks sand, is a finer product. It is generally used when the joints are 1/8 inch and smaller.
    • Epoxy grout contains no cement at all. It is made with epoxy resins and powder. This product is often harder and more durable than cement based equivalents, and it is practically stain proof. It is also much more expensive and can be more difficult to use than cement based grouts.

Step by Step Instructions

Follow these steps to grout tile for your outdoor patio:

  1. Clean first: Make sure all the tiles are clean. Using a utility knife, carefully scrape out any thin-set mortar (the tile adhesive that you used to bond the tiles to the concrete slab) that may have squeezed out between the tiles when you set them. This will be a different colour than the grout and will show through. Give all the tiles a wipe with a damp sponge.
  2. Choose a product: Choose one of the three grouts above, taking into account the size of your grout joints and the size of your budget. Grout comes in a variety of colours. Use the colour charts available at most home improvement stores to find one that works well with your tiles. Use the coverage chart on the back of the grout bag to determine how much you need for your project.
  3. Mix it: Follow the directions on the bag of grout powder carefully. Most grouts are mixed with water, but some are mixed with a liquid latex additive instead. This is recommended for outdoor applications as the latex can improve resistance to the elements.
  4. Spread it: Start with a small area. 3 feet by 3 feet is a good size. With your grout float, spread the grout, filling all the voids between the tiles. Do not worry about making a mess. It is all right to get grout all over the tiles.
  5. Remove excess: Use your float to wipe excess grout off the tiles. Cleaning up later will be easier if you do a thorough job here.
  6. Sponge it: Allow the grout to start drying before wiping it with a sponge. Make sure your sponge is almost dry. It should be moist, not wet. While being careful not to remove grout from the joints, gently wipe the tiles clean. Don’t worry about getting them perfect at this point. You will be wiping them again soon.
  7. Continue to grout the tile and remove the excess: Repeat steps 3,4, and 5 until all the tile has been grouted and wiped.
  8. Wipe it clean: With clean water, give all the tiles another wipe-down with a moist sponge. Rinse the sponge after every swipe to get them really clean.
  9. Buff it out: After the tiles have dried, some grout residue will remain. Buff the tiles with a clean towel or rag to remove the haze.

Now that you have learned all about grouting between tiles, you possess one of the most important pieces of information that you will need for successfully laying a tile patio in your garden.

Outdoor Tile Adhesives

When you are ready to begin setting tiles for your new patio, that is, bonding them to the concrete slab, you need to use the appropriate outdoor tile adhesive. There are many types to choose from. It is important to pick the right one. For an outdoor patio, you will almost always use a modified thin-set mortar for an adhesive.

Buying and Using Outdoor Tile Adhesives

Many homeowners are afraid to take on a DIY landscaping project of this sort, because buying the right products — and then using them properly — seems like a daunting task. Let’s set your mind at ease by posing — and answering — four questions:

  1. What is a modified thin-set mortar? It is mortar made with Portland cement, fine sand, water, and latex additives. Unmodified thin-set does not have the latex additives. We want the additives for our outdoor patio because they help reduce water absorption, improve the strength of the bond, and minimize movement due to changes in temperature.
  2. Where would you buy this type of tile adhesive? Modified thin-set mortar can be purchased at most home improvement stores (Home Depot, Lowes, etc.) and tiling shops. Be sure to tell the sales representative that you are undertaking an outdoor project so he or she can recommend the proper tile adhesive product. I do not recommend mastics and other premixed tile adhesives for use outdoors.
  3. How much tile adhesive do you need to buy? Thin-set mortar comes as a dry mix, usually in 50-pound bags. Smaller bags are sometimes available, as well. Check the coverage chart on the back of your bag to determine how much tile adhesive you need. On average, a 50-pound bag covers 60 to 100 square feet.
  4. How do you mix thin-set mortar? You will need an electric drill and a paint paddle/mixer. Most modified thin-set mortar products are mixed with water. Some are mixed with a latex liquid instead. Always check the directions on your bag. To mix with water:
    • Pour about 2 inches of clean water into a 5-gallon bucket.
    • Dump a small amount of the thin-set powder into the bucket.
    • Thoroughly mix the water and powder. Add more water or powder as necessary to create a paste with the consistency of the frosting you would find on a cake.

Each type of tile adhesive can have a different mixing procedure. Some of them need to be mixed, allowed to sit for ten minutes or so, and then mixed again. Your bag of modified thin-set mortar should have mixing instructions on it. Follow them explicitly for the best results.

How to Use a Grout Float

“Grout” is a thin, coarse mortar that is spread and pressed into cracks (also called “joints”) between tiles or other hardscape units to fill them (thus helping to keep water out) and consolidate the adjoining tiles into a solid mass. “Grouting” is the process of this spreading and pressing. A grout float is the tool used in this operation.

Not all grout is exactly the same, even if we limit the discussion to traditional grouts. One difference is in how ready it is to use when you buy at the home improvement store. Usually you buy it in powder form and then mix it when you get home. But you can also buy containers of premixed grout. If you have the kind that does not come premixed, you will mix it with water (the ratio of water to grout powder will appear on the back of the container) when you are ready to begin your project.

You also have to pick between sanded and un-sanded grout, and the deciding factor will be the size of the space between the tiles. If the cracks between the tiles measure 1/8 inch or less, buy un-sanded grout. When you will be grouting bigger cracks, shrinkage becomes more of a concern, and the solution is to use a sanded grout.

Grout comes in different colours, so you will want to choose a colour that complements your project. Finally, some grouts come with a latex polymer additive, which improves hardening of the grout. A strong bond is important for a patio that has to withstand the elements outdoors, making a grout with a polymer additive a good choice for such projects.

What a Grout Float Looks Like, How to Use One

The bottom of the grout float, the part that is used to actually spread the grout, is usually made from rubber. The handle can be wood or plastic.

Using a grout float is messy business but basically straightforward. You dab some grout onto your tool and start spreading it across the tiles, holding the tool at a 45-degree angle. The principle is the same whether you are grouting indoors, for a bathroom, or in patio work in the garden, when laying tile for an outdoor patio.

Although the idea is to work grout into the cracks, you will inevitably get a lot of it on the tiles, too. That is perfectly all right when grouting tile, so do not panic: You have not done any real harm, because the grout can be wiped off later easily enough. While you are grouting, keep a tile sponge and bucket of water close by for this purpose.

While on the subject of cleanliness, remember, too to keep your grout float clean. Periodically rinse off your grout float. It will be easier to spread the grout if the tool is clean.

If you are undertaking a large DIY project, choose a grout float that feels comfortable in your hand. Try out different models at the hardware store before buying. If you have a big job in front of you, a little bit of extra comfort makes a huge difference.

Grout floats can be found at most home improvement stores. Beginners will be surprised to learn that there are various types of grout floats. If you are using epoxy grout (a non-traditional type of grout), choose a grout float made to be used with epoxy grout.

Floats for Working with Concrete Are Different

In fact, when we employ the term more generally, there is an even greater variety of different kinds of floats, so you have to be careful when shopping. Hand floats meant for concrete work can be made from aluminium, steel, magnesium, resin, or wood on the bottom. Resin and wood types will make marks on the surface of concrete; this may be desirable if you are seeking to create a more slip-resistant surface. Metal types are preferred if you are not looking to create such “texture” and prefer, instead, a completely smooth surface.

Despite all of these different materials used to make concrete floats, the concept is the same: A concrete float is a spreading tool used in masonry, having a handle fastened to a flat piece. Such floats are used, for example, to finish the surface of a concrete patio or walkway. Employing an arc-shaped, sweeping motion, you smooth over bumps in the concrete surface with the float.

Then there is the “bull” float (also used for working with concrete), a large tool equipped with a long pole for a handle, so that you can reach out over the surface of a concrete patio to smooth it out, without stepping on it.

By David Beaulieu