Build a Slate Patio
Build a beautiful slate patio in hours—not days
DRAG A screed across the 2x4 frame to level out the sand and create a 2-in.-deep recess for the patio panels.
If your back muscles ache at the mere thought of building a slate patio, you're in for a pleasant surprise. A new panelized product from Vermont Natural Stoneworks offers a fast, foolproof way to build a beautiful slate patio or walkway - even if you've never done masonry work.
Called the Instant Patio System, it consists of 1/4-in.-thick slate tiles permanently adhered to 2-in.-thick polystyrene-foam panels. The tiles are laid onto a sand bed and the spaces between them are filled with traffic-grade sealant. No concrete to mix, mortar to spread or individual stones to set and grout. And because the panels are 2x2 ft. and 2x3 ft., you cover lots of ground in little time. Sound too good to be true? That's what we thought until we completed a 6x14-ft. entry patio in less than one day. This same project would have taken at least two weekends at the very least if we had poured a slab, waited for it to cure and then set each stone in a mortar bed. We also escaped without a single sore muscle or scraped knee.
Vermont slate comes in six earth tones: black, green, gray, red, purple and mottle (a greenish-purple shade). All six colors are used in the prefab patio panels, though you can also order specific color combinations. Square and rectangular slate tiles are adhered to the polystyrene with a flexible waterproof adhesive. The 3/8-in. spaces between each tile are filled with high-strength masonry grout. Durability is also part of the package. This system has been lab-tested to -40°F with no sign of failure or popped tiles. What's more, the 2-in.-thick Styrofoam base has an R-value of 10 for solid protection against frost heaving - crucial for areas where freeze/thaw cycles are common. Its thickness also provides a cushioning effect beneath the hard slate. The prepackaged patio kit comes in five popular sizes: 8x10 ft. ($600), 10x12 ft. ($900), 10x15 ft. ($1,125), 12x15 ft. ($1,350) and 14x15 ft. ($1,575). Or, you can order enough panels to build any size patio or walkway (about $7.50 per square foot). Either way, panels are shipped directly to your home along with all the necessary supplies, including rubber spacers, foam backer rod, tubes of sealant and installation instructions.
SET each panel onto the sand bed. The 2x2- and 2x3-ft. panels each weigh only 20 and 29 lbs., respectively.
Your first step is to build a perimeter border to establish the size and shape of the patio. We used pressure-treated 2x4s set on edge, but 4x4s, plastic edging or brick pavers will work too. As you're laying out the border, remember that you can avoid cutting any slate if you make the length and width of the patio roughly divisible by either two or three (the panels are 2x2 ft. and 2x3 ft.). Then remember to allow for 3/8-in.-wide spaces between the panels, except where they abut the perimeter. To build a 2x4 border, start by screwing together the four boards to form a perimeter frame. Set the frame right onto the ground and be sure the corners are square. While the frame need not be perfectly level, it should be close. Check it with a level, and dig out any high spots. Pound a 1x3 stake into the ground at least every 6 ft. around the outside of the frame. Drive the stakes just below the top of the 2x4s. Temporarily screw or nail each stake to the frame. Next, use a shovel and dig out about 1 in. of soil from inside the frame. Save the dirt for backfilling later. Spread about 3 in. of sand inside the frame, then compact it by pounding the ground with a hand tamper, which is basically a flat metal plate attached to the bottom of a long handle (you can rent one for about $8 per day). Compacting the sand helps prevent the patio panels from sinking. Then scrape the sand level using a couple of straight boards screwed together - known as a screed. To make one, cut a 2x4 at least 6 in. longer than the width of the patio frame. Then cut a 2x6 to fit within the frame. Screw the 2x6 to the 2x4 with the top edges flush. That will create a 2-in. overhang at the bottom where the wider 2x6 extends past the 2x4. Set the screed onto the frame with the 2x6 extending down into the sand. Then drag the screed across the frame with a helper. The 2x6 will screed off excess sand and create the uniform, 2-in.-deep recess needed to accommodate the patio panels. If you encounter any low spots while screeding, fill them in with sand and screed the area again.
An alternative to building a border: Dig out the patio area about 5 in. deep and toss in 3 in. of sand. Compact the sand, screed it off, then set the patio panels. The ground and grass around the recess will contain the panels. This borderless technique requires more excavation, but it creates a smoother transition because the patio is flush with the grass. It's also easier to mow around a flush patio.
CUT THROUGH the slate and its foam base using a circular saw fitted with a silicon-carbide abrasive blade.
Setting the Slate
Once the groundwork is complete, start setting the panels (photo 1). Use the rubber spacers provided to maintain a consistent 3/8-in. space between panels. If a panel must be trimmed, you can cut it to size using a circular saw fitted with a silicon-carbide abrasive blade. Slowly advance the saw across the panel, cutting through both the slate and polystyrene (photo 2). After setting all the panels, pull out the spacers and use a putty knife to push 1/2-in.-dia. foam backer rod between the panels (photo 3). The rod should be 1/4 in. down from the surface of the slate. Then use a caulk gun to fill the joints with the traffic-grade sealant (photo 4). The sealant is self-leveling, so there's no need to smooth it out. Let the sealant cure overnight. Finish off by removing the 1x3 stakes and backfill around the frame with soil and bark mulch. Then enjoy your new patio as you impress your friends with all the "backbreaking" work you put into it.
Where To Find It:
Depot St., Box 275, Dept. TH698, Fair Haven, VT 05743