Often, a deck is the most visible part of the backyard, so you don’t want to neglect it with a finish that looks like a sidewalk
But there’s no need to go to stone or exposed pebble to get a nice concrete deck. It’s easy to add flair just by using color. For a subtle touch of sophistication, you can give the concrete a sand finish by exposing the granules that already come in the mix
Regardless of which technique is used, a few guidelines should be followed in order to make the product look as consistent and attractive as possible. Here, experts offer tips on doing just that
A sand washed finish can upgrade a deck without the added cost of exposed aggregate. By applying the concrete, then washing off the top cream to expose the sand, applicators add a subtle texture and softness to the surface
“The colorant in the cement sort of takes a back seat to the color that’s in the sand,” says David Peterson, president of Watershape Consulting in San Diego, Calif. “But you still get the color.”
The process may help make the color of the concrete more consistent, especially if you’re cleaning off the top layer with an acid solution. “Even if you burned it, you’re basically taking the cement away and only leaving the sand there,” Peterson says
Follow these tips for a beautiful end product, whether using an acid solution or just wiping the cream off by hand
• Wet the concrete before applying acid solution.
Hose and saturate the whole deck first. The moisture will mix with the acid solution and prevent it from becoming too aggressive. “It’s being dispersed even further with the water,” says Jeff Lokker, owner of Huntington Pools in Glendora, Calif. Since the sand-washing process is done in sections, this step also helps prevent over-washing in those spots where sections overlap
• Start washing at the right time.
If not using a chemical agent, it’s especially important to know when to begin wiping off the top layer of cream. If done too soon, the whole slab will become liquified and come off. If too much time passes, the top layer won’t budge. “If someone started washing it when it was too wet, they would just dig big holes in the concrete and expose bigger pieces of aggregate, rather than just the sand on top,” says Scott Bohannan, president of Bohannan Concrete Inc. in Walnut Creek, Calif
Begin washing the surface of the concrete when the material is hard enough to walk on, but not too hard to remove the top layer. “It should feel very firm and hard, but still have enough elasticity where you could wash that top layer off, Bohannan says. “It’s a very fine line of knowing how to do that.” At that time, using the finest broom possible, wipe cream away and expose sand.
• Work lightly and review when finished.
Work off the cream a little bit at a time with a mild acid solution. It’s best to take two or three passes over the area rather than risk exposing too much aggregate by being too aggressive. This will prevent the deck from getting too rough
After each area has been washed and flushed with water, inspect the deck to make sure the finish is consistent. If not, it might be necessary to go over some spots again.
Some builders will encourage a color, even if the homeowner wants a straightforward broom finish with a gray deck
“The natural gray would be too gray,” Bohannan says. “It would be very bright, reflect the sunlight and not be as attractive.”
Of course, always warn customers that concrete is a natural material, and every batch will vary slightly in color. These differences are especially prevalent in integral color, where the coloring agent is added to the mud itself, leaving the hue throughout
“I would never warranty the color with any client,” Peterson says. “We do mock-ups sometimes and I’ll tell them: If you sign off on this, just know that when we’re all done, you cannot take this sample and line it up over the new deck and expect it to be the same.”
Here are some tips for getting the right colored finish.
• Show true samples if you can.
Try to steer away from referring customers to brochures with the color selection since the printed page is notorious for containing inaccurate reproductions
“It’s always a challenge to confirm what color the customer wants and to make sure that [they get it],” Lokker says. “That’s why we like to use color samples as opposed to a color chart on a piece of sales literature. We always try to use the actual concrete color chip charts so they can be more sure of what they’re getting.”
If using dust-on color, just make the little samples and then apply the color to each one individually. Since dust-on is more consistent than integral color, your samples will be closer to true
With integral color, things get tougher. “You’d have to buy two yards of concrete to make a sample, unless you happen to be pouring that color anyway,” Bohannan says
Look for a manufacturer who has made samples for customers to use. Hopefully these will show how the color looks in both a broom and sand finish, since the latter tends to lighten it
For higher-end customers who’ve narrowed their choices down to one or two selections, you can even go a little further and create a mock-up showing how the color will look against tile, paving or other materials that will be used in the area
• Consider a slightly darker integral color if sand-washing.
When creating a sand finish, it’s important to remember that the process will reveal the sand, but take away some of the color. If unable to get samples that show how each color will look after a sand finish, consider choosing a slightly darker color
“Sometimes you have to really convince the owners,” Peterson says. “I tell them that when we do this, it’s going to lighten up and the colors will fade over time as well. I explain that they might think it’s a little too dark in the first month, but after a year, it’ll look closer to what they want.”
Peterson may choose the next darkest color on the chart, or adjust the recipe to add another box or two of the color to the concrete
However, this tactic carries some risk and should only be used by an experienced professional, Bohannan says. “I think you’re asking for trouble ordering it darker than what they want, because if it doesn’t satisfy them, it would be you who made the call,” he says
• With integral color, put a premium on a consistent sub-base.
In any situation, it’s important to avoid part of the deck sitting on wet ground while the other is on dry. This becomes especially crucial when working with an integrally colored deck
If it sits on top of water, concrete will act like a sponge and absorb any moisture underneath. This will change the way the material sets, with the wetter portions taking longer. As a result, the colors in these two sections will be different
“Integral color has a tendency to want to blotch,” Bohannan says. “So if the ground’s wetter in one section and drier in another, that could make the color blotch and dry inconsistently. If there’s sand on one part, rock on another and dirt on another part, then it can make the color cure out differently and have potential blotching or discoloration.”
• Plan pours to work around color inconsistencies.
If you order more than one truckload of integrally colored concrete, you may have a slight variation between the batches
“There are so many variables, and some of them are totally out of our control,” Peterson says. “For example, the concrete truck could get stuck in traffic and take another 20 minutes to get here. That affects the curing time. And you might have three truckloads in one day, and two of them might get here really quickly and the other might be an hour and a half late.”
To work around this, Peterson will plan his pours ahead of time. “We’ll say, ‘OK, we want the first pour to be here so that we have consistency at least in that section, and then everything else can be the second pour,” he says. “I wouldn’t want the two different pours on two different days to be the first thing you see when you go into the yard.”
Try to pour the main deck with the same truck, if possible. Then side items such as walkways, planters and planter caps — if they’re separate from the main deck —can be made from a different truck.