Create a DIY Sunken Concrete Oasis

Ever admired the sleek, modern look of sunken concrete patios or driveways? Have you wondered how you could achieve that look in your own DIY project? With a bit of planning, the right materials, and some elbow grease, you can create gorgeous, sunken concrete features that'll not only elevate your outdoor space but also add valuable curb appeal to your home.

Before you begin, it's crucial to understand that this isn't a rushed weekend project. Creating a sunken concrete space requires careful planning, precise measurements, and patience. But don't worry; we've broken down the process into easy-to-follow steps. By the end of this guide, you'll be well-equipped to transform your backyard into a modern oasis.

Understanding Sunken Concrete Construction

In essence, sunken concrete involves digging a pit, building a form for pouring concrete, and creating a sloped footer to ensure proper drainage. The result is a smooth, seamless surface that appears to be naturally settling into the ground.

To ensure your project adheres to local building codes and regulations, it's crucial to check with your homeowners association (if applicable) and your local zoning department. In many cases, you'll need a permit for structural changes to your property.

Choosing the Ideal Location

Selecting the perfect spot is crucial. Consider factors like proximity to your home, drainage, and whether you'll be incorporating any landscaping elements. Avoid areas prone to frost heave, and if possible, choose a location that's mostly flat.

Once you've picked the perfect spot, measure and mark out the dimensions of your sunken concrete space. Use stakes and string to create a clear outline, ensuring the corners are square and the sides are even.

Preparing the Site

Now that your site is marked, it's time to start digging. Use a shovel to remove the topsoil and a hoe to loosen the soil before using a rented or rented-soil Bauer trencher or a similar tool to dig the pit. Make sure your depth is consistent across the space.

After you've dug down, use a level to create a flat base. For smaller projects, avoid using a machine; instead, use a shovel and rake. Next, create a 45-degree slope for at least 10 feet around the perimeter of the pit for drainage. This is crucial to prevent water from pooling and leading to cracks in your concrete.

Building the Form

Building a form for your sunken concrete involves creating a frame that will hold the liquid concrete in place as it sets. There are various methods to build a form, but the most common is using pressure-treated 2x6 lumber.

Cut your lumber to length, ensuring it's level and square. Use stakes to secure the forms in place. Make sure the forms are flush with the ground level where your concrete will meet the surrounding patio or yard. Then, attach the forms to each other using wooden stakes or screws.

Setting the Footer

Creating a solid footer is crucial for preventing cracks in your sunken concrete. Start by laying a base of 3 inches of gravel in the bottom of your pit. Compact the gravel using a plate compactor rented from a home improvement store. Then, lay a layer of #4 stone on top of the gravel to act as a base for your footer.

Use concrete blocks or cinder blocks to build your footer. Stack them to create a 45-degree slope along the perimeter of the pit. This slope helps with drainage and ensures your sunken concrete has a solid foundation. Fill the voids between the blocks with concrete, creating a solid footer.

Preparing for Concrete Pouring

Before pouring concrete, lay down a vapor barrier, such as plastic sheeting, on the footer. This prevents moisture from seeping out of your sunken concrete, which could lead to cracks. Also, ensure your forms are securely in place and that all welding or braced points are tight.

For small projects, you may be able to mix the concrete yourself using a wheelbarrow and shovel. However, for larger projects, consider renting a concrete mixer and having the concrete delivered. Regardless of the method, make sure your concrete has a consistent mix and is the right consistency for pouring.

Pouring and Finishing the Concrete

The actual pouring of the concrete is the most critical step. Start at one corner of your form, and use a rake to spread the concrete evenly across the footer. Once you've established a base, use a shovel to build up the concrete, working from one side of the form to the other.

After you've poured the concrete, use a bull float to smooth the surface. Then, use a trowel to level it out. Finally, use an edger to create a smooth, beveled edge where your sunken concrete meets the surrounding ground. Don't forget to remove your forms!

Curing and Sealing

Curing is the process of keeping your concrete moist as it sets. After you've finished leveling your concrete, cover it with damp burlap or plastic sheeting. Ensure that the water doesn't evaporate too quickly, as this can cause cracking.

After your concrete has cured for about 72 hours, remove the burlap or plastic. Inspect your concrete for any spots where water may have pooled. If you find these, use a concrete sealer to prevent water from being absorbed, as this can lead to cracking. Apply the sealer according to the manufacturer's instructions.

Now that your sunken concrete has cured and been sealed, you can add final touches like landscaping, outdoor furniture, or a fire pit. Remember, creating a sunken concrete space is a labor-intensive project, but the end result is a stylish, functional, and valuable addition to your home. So, grab your tools, roll up your sleeves, and let's get started!