Exposed Aggregate Concrete
What It Is, And Why You Should Incorporate It into Your Next Construction Project
Exposed aggregate has become a popular decorative concrete choice due to its aesthetic appeal and durability. It’s completely customizable and fairly easy to install, making it a cost-effective option for decorative concrete around the home.
Here’s a look at all there is to know about exposed aggregate concrete, including its different uses, the different types, and the benefits of using it.
What Is Exposed Aggregate?
Exposed aggregate is a type of decorative concrete that is often created by removing the top layer of cement paste to reveal (expose) the aggregate in the concrete mix. The aggregate can also be placed in fresh concrete.
Common aggregates used in exposed aggregate concrete include:
- Decorative stone
- Crushed stone
- Pea stone
- Crushed glass
Exposed aggregate concrete is not only used for its aesthetic appeal, but it is also durable and skid-resistant, helping to make walkways, driveways, pool decks, and patios safer.
Types of Exposed Aggregate
There are several methods for creating exposed aggregate concrete, including:
This is the most common method for exposed aggregate. It involves mixing or batching the aggregate in the concrete mix at the concrete plant first before delivering and laying the concrete at the project site. Pea stone is one of the most common aggregates used in the standard method.
Also known as a concrete overlay, this method is used to upgrade the look of existing concrete that is still in good condition. Aggregates are mixed into a concrete overlay batch and applied to an existing concrete slab in a thin layer that is 1 to 1.5-inches thick.
For the seeded the method, the decorative aggregates are placed by hand or broadcast on the surface of the freshly-poured concrete and then floated into the concrete by hand.
The polished method is the most common method for exposed aggregate concrete inside homes. This method is similar to the standard and topping methods. But instead of leaving the aggregate exposed with a textured, slip-resistance surface, a grinder or sander is used to work the top layer down.
Several clear coats of sealer are applied to create a shiny, polished surface. But if you want a matte finish, this step can be skipped.
How to Expose Aggregate
There are several ways to expose the aggregate in concrete. And a general rule of thumb is to remove the surface cement paste at a depth that is no more than one-third the diameter of the aggregate.
Brushing and Washing
This method requires washing away a thin layer of the surface cement paste by spraying it with water and scrubbing it with a broom until the desired depth of aggregate is exposed.
This method is best for small jobs and can begin as soon as the surface cement can be removed without dislodging or overexposing the aggregate. To test if the concrete is ready, lightly brush away a small area of the surface cement paste using a stiff nylon-bristle broom.
Using a Surface Retardant
After placing the concrete, the top layer of cement paste is kept soft by spraying on a surface retardant to slow down the curing process of the surface as the underlying concrete hardens, locking in the aggregate and reducing the risk of dislodging aggregates.
After several hours, once the underlying concrete sets, the top layer of cement paste is rinsed off with a pressure washer or garden hose or is scrubbed off using a broom and water.
Once the concrete has set and hardened, you can expose the aggregate using abrasive blasting, such as sandblasting or shot blasting. This method is not recommended if you want to preserve the colour and shape of the exposed aggregate since it can fracture and dull the appearance of aggregate.
Uses for Exposed Aggregate
Here are some of the most common uses for exposed aggregate concrete around the home:
Along with boosting your home’s curb appeal, an exposed aggregate driveway provides traction for vehicles, which is especially useful in slippery conditions, such as rain, snow, or ice. This traction also helps you get in and out of your vehicle safely with a more secure footing.
Exposed aggregate pool decks create a beautiful and safe surface to walk on, even when wet. To enjoy the slip-resistant and aesthetic benefits of exposed aggregate concrete without being too rough to walk on barefoot, you can opt for smaller aggregates or aggregate that is not deeply exposed.
The uneven surface of exposed aggregate concrete works well as a sound barrier for homes since it absorbs sound waves and reduces echoes. Exposed aggregate concrete is also often used as sound barriers along highways.
An exposed aggregate patio can bring your whole outdoor living space together by complementing your outdoor décor with this customizable decorative concrete. Its durability and low maintenance make for a stress-free patio material option that will look great for years to come.
Benefits of Using Exposed Aggregate
There are many benefits to using exposed aggregate as a decorative concrete option for your home. These benefits include:
Exposed aggregate is an aesthetically-pleasing decorative concrete. Exposed aggregate concrete uses decorative aggregates in various shapes, sizes, and colours to match any exterior décor.
This completely customizable concrete can blend well with other types of decorative concrete around your home, making for an attractive unique look that boosts your home’s curb appeal.
Exposed aggregate concrete has the structural integrity of concrete, so it is highly durable and can last for 40 years or longer. It holds up well to heavy traffic and can handle exposure to all the elements, including extreme weather, rain, sun, snow, and ice.
Exposed aggregate requires little maintenance aside from cleaning with water on occasion and re-sealing every three to five years to protect it and maintain its glossy appearance.
Exposed aggregate concrete is relatively easy and cost-effective to install. Since few additional materials are needed to create exposed aggregate concrete and it’s a relatively simple procedure, you can get this decorative concrete at a reasonable cost.
The skid-resistant quality of exposed aggregate makes these types of surfaces safer to walk and drive on, especially in wet conditions. The exposed aggregate contains small stones that give the surface texture, making it skid-resistant and also reducing the risk of slips and falls.
Consider the many uses and benefits of exposed aggregate for your next decorative concrete project. Exposed aggregate is a cost-effective option for decorative concrete that will look great, make surfaces safer, and last for decades with minimal maintenance.