Maria - Interior Designer
Welcome to our exposed aggregate patio design guide with pros and cons, cost and maintenance tips.
What Is An Exposed Aggregate Patio?
Exposed aggregate is a popular type of decorative concrete which is created by removing the top outer layer of cement paste to expose decorative coarse aggregate in the concrete mix. These aggregates can either be batched into the concrete mix or seeded on to the surface.
The common aggregates used for exposed aggregate concrete include decorative stones, gravel, crushed stone, pea stone, crushed glass, quartzite, granite, limestone, and basalts. Aggregates can be fine or coarse.
Due to the unique aesthetic appeal, durability, and skid resistance of exposed aggregate concrete, it is ideal to be used in pathways, sidewalks, driveways, swimming pools, pool decks, plazas, steps, and patios. 
Types of Exposed Aggregate Patio Methods
There are several methods for creating exposed aggregates:
Standard type – It is the most common method which involves mixing or batching the aggregates in the concrete mix.
Topping – This method is also known as concrete overlay wherein aggregates are mixed into a concrete overlay batch and then applied to an existing concrete slab. This method is used in upgrading existing concrete by applying a thin layer of aggregate mix at about 1 to 1.5 inches thick.
Seeded – This method is done by placing the decorative aggregates by hand on the surface of a newly poured concrete and then floated into the concrete.
Polished – Yhis method is most common for interior surfaces; similar to the standard and topping method this is also known as honing. This is achieved through grinding or sanding the top layer of the concrete to achieve a natural stone and flat matte finish.
To get to expose the aggregate in concrete, there are several ways to do so – usually it is done through washing or spraying with water and brushing or scrubbing off a thin layer of the cement paste surface until the aggregate is exposed.
Another method is by using a surface retardant spraying it on the top layer of the cement paste to slow down the curing process while the underlying concrete hardens. After the concrete sets, the top layer of cement paste is rinsed off using a pressure washer or scrubbing it off using a broom and water from a garden hose.
If you want to preserve the color and shape of the exposed aggregate, you can expose the aggregate by using abrasive blasting such as sandblasting or shot blasting once the concrete has set and hardened.
Exposed Aggregate Patio Pros and Cons
Match your home’s style – In choosing exposed aggregate as a decorative concrete option for your patio, you can achieve a lot of benefits such as it is completely customizable concrete and can blend well and match any exterior décor. Because of its unique, aesthetic look, it can boost your home’s curb appeal.
Very durable – Exposed aggregate patio is highly durable since it has the structural integrity of concrete, it can lasts 40 years or longer. It has a finish that is generally more durable than stamped concrete patios which is another alternative.
Helps prevent slipping – It holds up well to heavy traffic since the surface is textured and has a skid resistant quality especially in wet conditions making your patio surface safer and reduces the risk of slips and falls.
Stands up to adverse weather conditions – Exposed aggregate can also withstand exposure to all elements and extreme weather.
Somewhat low maintenance – It also requires moderate maintenance other than occasional cleaning with water and re-sealing every three to five years for protection and maintaining its glossy appearance.
Low cost – Using exposed aggregate for patio can also be cost-effective to install with its relatively simple procedure and reasonable cost.
Exposed Aggregate Patio Cons
Though exposed aggregate patio may be unique and has more aesthetic appeal, it also has several disadvantages to consider before you decide to install an exposed aggregate on your patio.
Can break down if top concrete layer is damaged – Installation of exposed aggregate poses its own challenge and one must work carefully so he don’t overexpose the aggregate regardless of whatever methods one uses.
Exposed aggregate can be as strong and long lasting as concrete, it is the decorative stones on the top layer which are more prone to damage.
There are many factors that can make these exposed aggregate vulnerable to damage such as movement of heavy objects, water damage can loosen or dislodge the small stones leaving rough pits in the surface; water can also weakens the bond between the concrete and aggregate.
Difficult to repair – Repairing cracks in exposed aggregate is more difficult since blending the patched surface with the rest of the flooring is the toughest part.
Challenging to clean & maintain – Lastly, cleaning and maintenance of exposed aggregates on these types of patios are not as simple as they seem. You need to really need to scrub with wire brush and use a powerful hose to wash off all types of dirt that get compacted between the exposed aggregates.
Exposed Aggregate Concrete Patio Cost
The Basic aggregate concrete patio material price for 100 square feet area can cost around $125 to $150 while the Best aggregate concrete patio material price for 100 square feet area can cost around $200 to $235.
The Basic aggregate concrete patio installation cost for 100 square feet area can cost around $150 to $175 while the Best aggregate concrete patio installation cost for 100 square feet area can cost around $300 to $500.
The average total price for labor and materials per square foot is $10.15 and can cost around $9.11 to $11.18.
For a typical 100 square feet area patio, the Total labor and materials can cost around $275 to $325 for the Basic aggregate concrete patio labor and materials; while the Best aggregate concrete patio Total cost can range from $500 to $735 for both labor and materials.
Exposed Aggregate Concrete Patio Sealer
The exposed aggregate need to be sealed to help protect it against spalling, dusting, efflorescence, freeze-thaw damage, stains, abrasion; it also enhances the color of the aggregate and highlights the aggregates’ depth and richness.
When selecting a sealer for exposed aggregates, there are some elements which you need to check. Make sure that the sealer you choose is non-yellowing and UV resistant, the sealer should repel oil, grease, water and stains.
The sealer needs to provide a high-gloss wet look – this is an element which deepens and enriches the color of the aggregate.
There are two best types of sealers for exposed aggregates – Water Repellent Concrete Sealers and Acrylic Concrete Sealers.
Water Repellent Concrete Sealers – Water Repellent Concrete Sealers won’t change the look of the concrete, it works below the surface and lasts 7 to 10 years. This type of sealer repels surface water and reduces staining and deterioration; and can be used on cured and uncured concrete.
Acrylic Concrete Sealers – On the other hand, Acrylic Concrete Sealers enhances the aggregates with a wet look or gloss while leaves a visible surface film and lasts 1 to 5 years. This type of sealer also protects the surface against staining, stops dusting and deterioration; and just the same can be used on cured and uncured concrete.
It is important to make sure that all cement paste residue has been removed when applying the sealer to fresh concrete in order to avoid sealing the milky-looking white paste on the surface.
If you need to apply sealer on existing exposed aggregate make sure that the surface is thoroughly clean and free from oil, grease, dirt and stains before applying the sealer.
Cleaning Exposed Aggregate Patio
As time passes by, exposed aggregate patio will get dirtier since it will be gathering dirt, dust and debris.
Regular maintenance and cleaning is of utmost importance in order to protect your exposed aggregate patio and retain their fantastic look. To help with this, we have put together some information on how to clean your exposed aggregate patios without causing damage.
Ideally, sweeping your patio at least once a day keeps it free from dust, dirt and debris. For stain spots and stubborn dirt, rinsing the surface with water using a garden hose is a good idea.
To eliminate oil and grease stains, use a high pressure washer with hot water to help lift the oil and grease from the surface and apply a cleaning solution which will break down the stain; by doing so, it allows the oil and grease to wash off easily.
Usually, a cleaning solution will just call for a dishwashing liquid or baking soda; but tough oil and grease might need a commercial-grade degreaser to do the job.
Any moisture that is left to settle on your patio which, at the same time has very little sunlight can easily start to form mold and algae. These molds and algae are to be cleaned by using a chemical solution and washing it out with a high-pressure cleaner.
It is important that whenever you are using a chemical cleaning solution, your exposed aggregate patio needs to be rinsed and allow the surface to completely dry.
We hope that we have presented to you a lot of options for incorporating exposed aggregate onto your patio and anywhere you see it fit the landscape of your home.
Using exposed aggregates in your patio is a great choice – it is very versatile that you can get quite creative with shape and positioning.
You can achieve very interesting designs and layout styles by playing around with colors and aggregate materials as well as the size and shape of the aggregate.
For more related content visit our stone patio ideas page.
