A Practical Guide to Choosing Patio Materials
by Traven Pelletier (originally published in Michigan Gardener Magazine April 2014)
Paving an outdoor space is an age-old human activity—even a superficial look into the architecture of ancient civilizations yields stone pavement in almost every case. If you are interested in creating, renovating, or just researching what your options are for an outdoor patio, you are engaging in a wonderful, rich and historic human tradition.
With lots of local and national suppliers for paving materials it can also be a bit daunting to look at all the options. Here is a simple guide and approach to a patio project for your property.
The patio base
A patio is built from the ground up, and just like in a garden bed, the soil matters. What you put under your patio is as important as what you pave it with. If you have a heavy, compacted clay soil, making sure you have proper base that is drained well will help mitigate heaving problems down the road. If you have a sandy soil, you might not need to worry about drainage, but you will still need a strong, compacted aggregate base so that the patio doesn’t erode or shift due to the malleability of a sandy base. With that in mind, I always use 4 to 6 inches of compacted aggregate base—limestone or crushed concrete with “fines” in it (i.e., not washed out). Plus, I add an additional 2 inches of leveling layer of either sand (for a flagstone patio) or slag sand (pulverized limestone chips, for a paver patio). How smooth and uniform your patio looks and how long it stays even mostly depends on your base, so make sure its thick enough, well compacted, and even.
Now on to the fun stuff. The excitement in a patio is choosing the material itself—how it looks, the texture, color and design. There are three basic options, with a lot of variation. From the cheapest to most expensive: concrete, pavers, and natural stone.
Concrete patios are the simplest and most affordable. Generally, they are poured on a compacted sand base 6 to 12 inches thick to help prevent heaving and cracking. There are a lot of staining and stamping options available now, but I find that they tend to look somewhat fake unless it is just a simple texture. Stamped and stained concrete also tend to wear over time (5 to 10 years, depending on the quality of the installation). All concrete in our climate is going to heave and crack eventually, so don’t expect perfection in the long-term (10 years or more) with a poured patio. The advantages of concrete patios are cost, simplicity, and speed of installation.
Paver and brick patios are by far the most common patio options and there are countless products and variations. The difference between pavers and brick are the material and process: pavers are a concrete cast product, and brick is a natural clay product. Brick tends to be slightly more expensive. The advantage of pavers is long-term durability combined with the fact that since they are small units, they can be relatively easily repaired and re-laid (as opposed to a concrete patio which cracks and heaves and is difficult to patch, re-level, or repair).
There are now quite a few “natural stone” style pavers. Some are better than others, but the best ones tend to cost as much as natural stone. In my opinion their only advantage is that they are easier to lay than natural stone. My favorite pavers are “tumbled,” which means they are run through a drum and “softened,” resulting in a texture reminiscent of a traditional cobble.
Natural stone is my favorite material—its beauty is unmatched and like pavers it is easier to re-lay and re-use than concrete. If you can afford the extra expense of the material and additional labor to lay natural stone properly, it is worth it. Like the cobblestone streets and plazas of pre-industrial and ancient cities, natural stone patios evoke a connection with the elements and landscape. There are a wide range of options for patterns and design.
Natural stone varieties
Here in Michigan we have a variety of sandstone and limestone. Regionally, Pennsylvania and New York supply us with “bluestone,” which is a harder sandstone product. Generally, I do not recommend our local sandstone (which is a light tan, beige, or rust color) for patios because it is so soft. It weathers quite quickly (in the 5- to 10-year range) and will show significant flaking and cracking. On the positive side, it is quite affordable.
Limestone is expensive and a bit more difficult to work with because it is quite hard. It generally comes in smaller pieces out of the quarry, thus requiring more work piecing and fitting it together. Bluestone is probably our most optimal product regionally and my personal favorite. It has good strength and hardness for longevity and quarries well in big pieces, making it easier and more cost effective to lay.
Design and pattern
These matter just as much as the material and help determine the general feel and function of your space. The average back patio is around 300 square feet, which will give you enough room to cook and entertain for family and a few friends. Large families or outdoor spaces for gatherings over 8 to 10 people require more square footage. I often recommend looking at 500 to 600 square feet for an outdoor “entertainment” space.
Square-cut natural stone or pavers will yield a more formal or modern-looking patio. Incorporating curves or natural style stone shapes can give you a more informal feeling. Often a “border” course of stone or pavers laid in a repeating pattern is used to set off or divide the space (this is often referred to as a “soldier course”). Arches or strong circular radius shapes can also create a more formal-feeling patio. Creating levels or sections of a patio is common, but more expensive, since it involves building retaining walls to separate or raise the sections. Incorporating short bench walls and gathering spaces around firepits is currently popular and often a worthwhile addition for making the space feel cozy.
My favorite projects often incorporate a “tension” of some sort between materials or in the design itself. For example, a natural stone patio with a square cut rectangular stone forming the patio’s outer border, while a natural style, jigsaw-fit interior stone creates an interesting textural contrast. Similarly, a bordered paver patio with natural stone accents and vice versa.
I always recommend putting pen to paper or working with a good designer first. It is easy to get samples from suppliers and contractors, so playing with color and texture next to the house before deciding on a material is a good idea. Most of all, have fun creating the concept and playing with a number of products and designs before finalizing your choices. Done well, your patio will be something you enjoy for as long as you are in your home.