Landscaping with slate offers many attractive options and design ideas for homeowners. Slate is a versatile natural stone that can be used for building pathways, patios, and backyard hardscapes in general, creating charming and sophisticated outdoor living spaces. Let’s take a look at slate properties, pros and cons, and also explore some landscaping ideas.
What is Slate
Slate is a type of metamorphic rock that was derived from shale or mudstone which underwent metamorphism, a process by which one rock transforms into a rock with a different mineral composition. You could say, slate is a side effect of the creation of mountains, and that is why it’s typically found around the base of mountains. It has a sedimentary, flakey appearance, and is mainly composed of quartz, muscovite, or illite.
Can Slate Be Used Outdoors – Pros and Cons
Slate is well known for its extremely low water absorption, for this reason, it is commonly used as shingles on a roof. Its low absorption index makes slate stain and weather resistant, whereas the highest-quality slate is almost impermeable. If you live in a location with a frequent freezing/thawing cycle then I would strongly suggest using slate as a medium as it will resist cracking due to frost.
Many of the minerals that slate is composed of, including quartz and muscovite, imbue slate with extremely high resistance to chipping and scratching. Slate also boasts high flexibility and compressive strength, and won’t etch or erode over time.
Much like other natural stone pavers, slate can end up costing you a lot more than simple bricks or concrete. You may want to pay for sealant on your slate pavers as well, both to preserve the finish and to reduce slippage.
Slate Landscaping Ideas
The experts at Adrosia Slate said, “Slate has been used as one of the most popular natural stones for patios for a long time.” and I tend to agree with them. When I think of backyard design the look of dark grey slate accenting your garden walkway or sitting proudly on your terrace pops naturally into my mind. Thanks to the neutrality of the slate’s color, its durability, and its curb appeal, slate is one of the more versatile stones. When you begin walking down a pathway, approaching a patio, or lounging around the pool deck, your choice of stone will get noticed.
Walkways
I think of walkways as the opening presentation to your backyards. They’re the pipeline to the rest of your outdoor decor, and first impressions are the most important. The use of slate as your walkway, be it a monotone black or a multicolored canvas, adds a level of appreciation to your backyard. Its durability and resistance to moisture mean you can plant the pavers square in the ground without worry.
As natural stone is almost always associated with high class, going with a slate walkway is an excellent option to ferry your guests throughout your backyard.
Patio and Terrace
Image credit: Rochester Concrete Products
Whether you’re designing a patio or a terrace, slate is an excellent choice. The array of options between texture, finish, and color should allow even the most discerning of designers to find an option they like. Once again, slate is extremely durable which means high foot traffic won’t be a concern. If you intend to barbecue or install a kitchenette on your patio then I would consider going for a higher-quality slate due to its low absorption index. This means oil spills or food stains won’t leave you on your knees scrubbing them out with baking soda. If you don’t intend to do much cooking (or eating) on your patio, then a more cost-effective paver could work.
Pool Deck
Image credit: Rochester Concrete Products
Slate is an excellent choice of stone when designing your pool deck. Its textured, non-slip surface, and the interesting shift in color as it gets wet lends itself as one of the better stones. If you live in an area with excessively high temperatures, then you may want to consider a different option, as slates non-porous nature can lead to it heating up during hot summer days.
Backyard Staircases
Once again, the non-porous and near hydrophobic qualities of slate make them excellent for staircases. Whether you’re leading up to your 2nd level patio, your terrace, or even the steps leading into your pool, slate makes excellent stair treads. The splash of black or dark green against hardwood evokes a beautiful and timeless.
Types of Slate Pavers
Slate varies greatly depending on not just the location where it was quarried, but the minerals present during its composition and the way in which its mined. The most common color when we think of slate is dark grey, but beyond ranges of grey, we can rarer colors such as purples, greens, golds, reds, and blue. This will depend on the mineral content of the slate.
Some types of pavers, such as the Chinese slate, will come in a wide variety as the name denotes a large region with multiple quarries, whereas slate such as Vermont is typically mined in few locations and maintains visual uniformity in appearance.
Let’s discuss some common slate materials that you’ll encounter when landscaping your backyard.
Image credit: Stone Paving Direct
There is a gradient of quality when it comes to slates from the same region, and the Chinese slate is no different. While some of it can be extremely high quality, comparing it with the best Spanish or Brazilian slate you can find, a lot of it is considered low quality. Chinese slate can have high contents of lime, iron pyrite, and salt making it less inert and prone to erosion. Eventually, the salt content will cause a white bloom to show, or the iron pyrite will rust and cause patches of bleeding rust. While Chinese slate can be affordable, the quality can vary, and it’s best to get it from a reputable source.
Indian Slate
Image credit: Primethorpe Paving
Indian slate pavers are extracted from quarries in India and are known for their wide range of colors and durability. Interestingly, the black and dark blue slate from India is considered to be harder and more durable, while the lighter colors can be softer and may delaminate. Much like the Chinese slate, Indian slate may contain iron pyrite, but to a lesser degree. These pavers would be an excellent economical option if you’re thinking of buying some slate.
Brazilian Slate
Brazilian slate pavers are considered premium quality, most of them being mined in Minas Gerais. Brazilian slate is well known for its durability that can withstand heavy foot traffic if used as walkways or pavers for your patio. Brazil has made a huge impact on the slate market in the last decade, and its quality explains why. Overall this is considered to be one of the best slates to use outdoors.
Vermont Slate
Image credit: Sita Tile
Vermont slate is quarried from the Taconic Allochthon, a large block of rock that has been moved from its original site and wound up in Vermont. This slate is typically used in roofing and landscaping and contains high color variations and texture. According to the Department of Environmental Conservation, Vermont slate is produced through “drilling and blasting, followed by manual splitting”. This tells us that the slate is of a more brittle nature compared to some of the more durable cuts like Brazilian or Welsh slate.
African Slate
Image credit: Surfaces Reporter
When we talk about African slate, it covers a large variety of kinds due to the size of the continent and the number of quarries found. Found in Zimbabwe, Mozambique, and other regions, slate found in each quarry will have a distinct appearance and quality.
Welsh Slate
Image credit: Higher Ground
Considered by many to be the finest natural slate without equal. Coming in colors ranging from purple to blue-grey, and has been a favorite amongst designers and homeowners. Using Welsh slate in your backyard would bring a lot of class and value to your property.
Select your Finish
There are a few types of finishes that are suited to outdoor usage.
Tumbled
Slate is cut into pieces and then tumbled in a rotating container to give a surface a weathered, aging look. This is closest to your natural appearance and is well-suited for the backyard.
Honed Slate
Honed slate is more refined, with a smoother surface that more closely resembles a granite or travertine feel. Honed slate is matte and less slippery when wet than polished, but slicker than tumbled. This is a good option if you’re looking for something in between polished and tumbled.
Clefted
Clefted slate is slate in its most natural form with uneven surfaces resulting in an organic and textured appearance. If you’re looking to maintain a rustic look, then naturally clefted slate will represent that perfectly. The uneven surface will also act as a form of grip, so if barefoot walks along your pathway are in mind, then this finish could be for you.
Installing Slate Pavers
If you’re looking for how to install slate pavers, the method used is identical to installing travertine pavers.
Maintaining Slate
One of the great things about most natural stones is that it’s relatively easy to clean, but that doesn’t mean you don’t have to maintain them throughout their life cycle. I would strongly suggest that you begin your maintenance routine by sealing your slate pavers. You’ll want to begin by planning a few days without any rain, this will ensure your sealant isn’t washed away and your work ruined.
Brush your pavers off of debris, wash them, and let them dry. When ready, take your sealer, preferably acrylic as this will bond better with your stone, and begin applying a layer with a flat microfibre mop or a roller. Keep your coats thin, you don’t have to layer it on heavily, and allow at least 24 hours to dry.
I would typically avoid using any heavy-duty or astringent cleaners as they can cause damage and even erode your natural stones. Simple dish soap is completely adequate to return your pavers to their previous sheen and remove any sticky dirt or grime.
If you plan to do any cooking atop your slate pavers, then chances are you’re going to eventually get an oil stain. Don’t panic, there’s an easy solution: pour a layer of baking soda over the affected area and cover it with plastic wrap. The baking soda should pull the oil straight out of the stone within an hour.
The experts at StoneHardscapes advise that if you “wash and sweep the pavers regularly, there will be less need for a deep cleaning”, and they couldn’t be more right. Prevention is the best medicine.
Cost of Slate
The cost of slate is dependent on your style, color, and quality, but the fact that it’s a natural paver means it generally costs more upfront. Slate often ranges between 5.00$ and 20.00$ per square foot, and the accumulated cost can begin to add up depending on whether you’re doing a mud-set installation or a dry-set. When choosing slate as your backyard medium, expect 1/3rd of your total cost to go towards it.
Starting small, an average-sized walkway (45 sq. ft) made from clefted slate could cost roughly $350.00 in material and $150.00 in labor costs. This project should be comparatively easy to do yourself if you wanted to save some money and spend it elsewhere in your backyard.
Moving up in size, a patio can vary in dimensions, but an average-sized one will be roughly 160 sq ft. Now if you’re doing a mud-set method and getting a concrete substructure poured that will cost you roughly $900 including labor. Then we get to the slate itself, which will be around $1800 including labor. That’s $2700 for a medium-sized patio, but that cost can potentially be recouped by the increase in home value.
One of the biggest projects you can install is a pool and the accompanying pool deck which can get up to 900 sq. ft in area. Pool decks can be difficult to design as they tend to have unique shapes and angles which can increase the labor costs. A 900 sq. ft pool deck after material and labor can run you up to $12’000 if you’re using higher quality slate.
After the installation, you’ll need to seal your stone pavers to help preserve your investment and keep them looking fresh. You should ideally double-seal them with an acrylic sealant that can cost up to $130.00 to cover approximately 500 sq. ft.
References
– Paving and Patios. (n.d.). Welsh Slate. Retrieved May 10, 2023, from https://www.welshslate.com/hard-landscaping/paving-and-patios/
– Slate | Department of Environmental Conservation. (n.d.). Vermont Department of Environmental Conservation. Retrieved May 10, 2023, from https://dec.vermont.gov/geological-survey/resources-energy/minres/slate
– Natural slate production process. (n.d.). Cupa Pizarras. Retrieved May 10, 2023, from https://www.cupapizarras.com/usa/natural-slate-company/production-process/
– Gabrielsen, K., & McEvoy, S. (n.d.). Slate Patios. HGTV. Retrieved May 10, 2023, from https://www.hgtv.com/outdoors/outdoor-remodel/slate-patios
– Zakes, E. (2023, April 26). Why Businesses Use Slate In Outdoor Landscaping and Great Ideas to Consider. Earth Development. Retrieved May 10, 2023, from https://earthdevelopmentinc.com/blog/why-businesses-use-slate-in-outdoor-landscaping
– Nicolaides, P. (2022, March 28). How to lay slate paving the correct way. Buckinghamshire Landscape Gardeners. Retrieved May 10, 2023, from https://www.buckinghamshirelandscapegardeners.com/news/how-to-lay-slate-paving-the-correct-way
