Though water gets the bulk of attention, it’s the deck that often occupies much of the backyard vista.
As a result, deck specialists may be called upon to apply several types of products. They must serve as generalists, possessing wide-ranging skill and knowledge.
Easier said than done in some cases.
“A lot of people have had one job where they’re a carpenter, say, and all they did was hammer nails,” says Ed Sixberry, owner of Florida Concrete & Coatings Inc. in Satellite Beach, Fla. “But we cover the field: We’re pressure cleaning, prepping, doing concrete. Sometimes we’re forming or painting. In one week we could be doing five different things.”
Over time, and with the proper training, a decking professional can become a master of the craft. Here, deck experts share tips for setting paver and stone decks.
For years, paver decks were installed either on a sand bed or placed on a sturdier concrete deck.
But in the past 10 years, a new option has emerged. Polymetric, or stabilizer, sand comes in several colors and is treated with a polymer additive.
“Wetting [the material] activates the polymer [in the sand],” says Bill Renter, owner of The Deck & Patio Co. in Huntington Station, N.Y. “It gets sticky at first. Then, when it dries, it gets hard. It adheres to the bottom and sides of the stones. It’s a lifetime installation, so you can hose it down. The polymer doesn’t wash away, [and] the sand doesn’t wash away because it’s gotten firm.”
The crew uses it just like traditional sand, first setting layers of crushed stone, then placing the sand. Next, they lay down the pavers and fill the joints with more sand. These sands come in various grits, with larger ones more suitable for larger joints.
Afterward, the crew breaks out the hose.
Only a light mist is required to activate the polymer on top of the deck; ground moisture does the job underneath.
Additionally, grass and weed seeds can’t germinate in the hardened substance, so nothing will grow between the joints.
Over time, if pavers crack or move, they can be pried out and replaced. New sand is added, and then watered. And because the sand doesn’t discolor, the new material should match the original
- When building on a sand bed, secure the base.
Sand has distinct benefits over a concrete sub-deck. For one thing, it can move without cracking. But it must be carefully secured in place.
Each layer — the soil, a minimum 8-inch layer of crushed stone, and 3/4-inch to 1 inch of sand — must reflect the desired slope on the finished deck.
This ensures consistently thick gravel and sand layers, which in turn promote equal movement throughout the deck. Do not wait for the sand bed itself to receive proper grading.
To keep the sand in place, consider building a cement footing around the paver deck.
“You don’t want rainstorms to wash the sand out,” says Irv Chazen, president of Custom Pools in Miami. “This keeps the pavers in place as they were at the time of installation.”
The footing can be made of concrete or block, and is set under the outer rows of pavers. It should be elevated enough so the pavers placed on top of it are the same height as the others.
But Renter uses a different method to contain the sand. His crew places 1-inch steel pipes around the perimeter, then at 8-foot intervals in between. This holds the sand in place while the crew screeds it flat.
After polymmetric sand is “activated” with water, the pipes are removed. The crew then hand-fills any gaps left by the pipes in the bed.
The pipes also help determine whether the gravel bed underneath is level. If any gravel dips more than 1/4-inch below the top of the pipe, adjustments will have to be made.
- Know when to use a plate compactor, and when not to.
Once in place, the pavers may need a little help burrowing into the sand. For concrete pavers, Renter uses a plate compactor, which vibrates the pieces down in the sand while forcing sand up into the joints, thus interlocking the pavers and the sand bed.
“You do it in more than one direction,” he says.
“It’s almost like a lawnmower: You’d run it across the pavers one way, then do it perpendicular so they’re fully compacted in.”
When building the deck with natural stone, however, avoid this step. It can crack the stone.
- Work with the sub-deck joints.
If working with a concrete sub-deck, you will need joints to allow for movement and control cracking. Yet full pieces of stone must sit on top of the deck.
If you’re working with rectangular pieces, you may be able to set and cut the stones to expose the joints underneath.
But don’t use this technique on random-patterned stone — it ruins the look, interrupting the curving joints with large, straight ones.
Instead, you need to create separation between the joint below and the mud bed you’ll use to attach the stone.
Place a crack-control fabric measuring 12- to 24 inches wide directly over each joint. This will allow the deck underneath to move while the stone on top stays put.
“Some of it comes self-sticking; some of it is just a fabric that you embed in a little bit of thinset,” notes Thom Blumenkamp, sales and design specialist at Texas Pools in The Woodlands, Texas.
Next, place the mud or thinset, and proceed as usual. This allows the concrete to move normally.
“So the stone veneer that sits over the crack has someplace to move, and the crack doesn’t come through to the surface,” Blumenkamp says.
Setting stone in a random pattern requires planning as well as improvisation. You can’t predict where every piece will go, but you must retain some control over the final product.
“I’ll see people start it at one end of the deck and then work to the other end,” Blumenkamp says. “They wind up with full pieces on the side they started, and on the side they end with, just a little sliver.”
Choose a good starting point — somewhere in the middle of the deck. Begin by laying out full stones, and working out toward the sides. This relegates any cuts or tiny pieces, which you may need to ensure uniform coverage, to the deck’s perimeter.
And closely monitor the placement of each stone.
“All stones have what I call a face and a back,” Blumenkamp says. “It’s very obvious if you put the wrong side up, so make sure that the good side is always up.”
- Ensure each stone is level.
Stone is a natural material that varies in thickness. One piece might be 1/16-inch higher than another. In the case of flagstone, there’s even more variation.
This can create practical, as well as aesthetic, problems.
“If you don’t get it level on the top, you’ll have little sharp edges that stick up,” Blumenkamp says. “It won’t bother you when you’re in shoes, but when you’re in bare feet, it becomes obvious.”
Each piece must be set level with the rest. If it is thinner than most, lay down a thicker mud bed, tamp it down for a good bond, then check the elevation relative to the others.
- Wait a day for colored grouts.
When applying a simple gray grout, you may use the mud mixture that adheres the stone to the sub-deck. Apply a coat thick enough to allow some to ooze out between the stones. If it’s still uneven, add more in the joint to create a monolithic layer.
If you plan to return with a colored grout, however, be sure to allow the newly veneered stone deck to sit for at least 24 hours.
Then simply apply the mixture between the joints, scrape off any excess, and sponge clean.