Build Your Own Stylish and Sturdy Concrete and Cedar Outdoor Bench

Benches have always held a special place in the world of seating. They represent a simple, functional, and timeless design. When you consider it, almost anything can function as a bench if you find a comfortable way to sit on it. Inspired by this versatility, I embarked on a journey to create my own DIY bench, focusing on a modern concrete and wood design with a sleek profile and a robust frame. This guide will walk you through the process of building your own stunning concrete and cedar outdoor bench.

The concept of benches dates back to ancient times, serving as practical and adaptable furniture pieces. Their inherent simplicity and functionality make them ideal for DIY projects. My fascination with concrete and wood combinations led me to explore various designs, culminating in the creation of this elegant bench using concrete and classic cedar.

The result is a simple, sleek, and incredibly sturdy bench perfect for any outdoor space. This step-by-step guide provides all the necessary information to replicate this project and create your own unique piece of outdoor furniture.

Materials You’ll Need

Concrete Mix: 3 – 80-lb. bags of high-quality concrete mix, such as Quikrete® Countertop Mix. This mix is ideal for a smooth finish and easy consolidation.
Cedar Board: 1 – 2″x10″ cedar board. Cedar is naturally resistant to rot and mold, making it an excellent choice for outdoor use.
Melamine Sheet: 1 – 2’x4′ sheet of melamine (commonly found in the closet shelving section). Melamine provides a smooth, non-stick surface for creating concrete molds.
MDF Boards: 3 – 1x4x8 finished MDF boards. These boards are used for constructing the concrete molds.
Optional Tools: Angle grinder and sanding pads for smoothing and polishing the concrete surface for a more refined look.
Safety Gear: Gloves, goggles, and a mask to protect yourself during the concrete mixing and handling process.
Additional Supplies: Kreg Jig (optional), coarse-threaded screws, nail gun, 18-gauge nails, latex caulk, concrete release agent (or cooking oil spray), wheelbarrow, shovel or hoe, measuring tape, saw, rubber mallet.

Note: I partnered with Quikrete® for this project and used their countertop concrete mix, which contains an additive that improves flow and consolidation at a lower water-to-cement ratio. This mix is excellent for countertops and any concrete project where you desire a flawless finish.

Step-by-Step Guide to Building Your Bench

Step 1: Creating the Concrete Leg Molds

The first step is to construct molds from melamine to form the concrete bench legs. I designed my bench legs to be 17″x23″ rectangles with a 3″x11″ void for the cedar board to rest in. Adjust these dimensions to suit your desired bench size and aesthetic.

We aimed for a bench seat height of 19″ from the floor, a pretty standard and comfortable height.

When constructing concrete forms, keep the following points in mind:

Use Melamine: Opt for melamine or a similar coated material. The smooth, impermeable surface facilitates easy removal of the forms from the cured concrete.
Inner Rectangle Construction: Avoid encasing the melamine in concrete. Construct the inner rectangles as small, four-sided boxes with a small space in the middle, or use rigid foam for the bench cut-outs for easier removal.
Assembly: Use a Kreg Jig and coarse-threaded screws or a nail gun and 18-gauge nails to assemble the forms securely.

After assembling the forms, seal all seams with latex caulk to ensure they are watertight, preventing concrete mix from leaking out.

Step 2: Mixing the Concrete

Since the project didn’t require massive amounts of concrete, I chose to hand-mix it in a wheelbarrow. Begin by pouring the concrete mix into the wheelbarrow and creating a trough in the center of the dry mix. Gradually add water according to the instructions on the concrete mix bag.

Thoroughly mix the concrete with a shovel or hoe until it reaches a thick, lumpy oatmeal-like consistency. Be careful not to over-mix or add too much water. For a decorative touch, consider adding liquid cement color to the mixing water.

Safety First! Always wear gloves, goggles, and a mask when mixing concrete. Avoid contact with skin, eyes, and inhalation of dust.

Step 3: Pouring the Concrete

Spray the inside of the molds with a concrete release agent or cooking oil spray to prevent the concrete from sticking. Carefully pour, or rather, lump, the concrete into the molds, starting in a corner and working your way around. Ensure that the concrete fills all corners and narrow areas completely.

Step 4: Vibrating the Forms

Use a power tool, such as a reciprocating saw (without the blade) or a hand sander, to vibrate the forms. This process helps eliminate air bubbles from the concrete, resulting in a denser and more uniform finish.

Step 5: Screeding the Concrete

Screeding involves using a straight, sturdy board (such as a 2×4) to remove excess concrete from the top of the form. Employ a sawing motion, moving the screed board back and forth while pulling it along the length of the form, to achieve a level surface.

Step 6: Finishing the Concrete

Allow the concrete to set until the bleed water (excess water) is re-absorbed. The concrete is ready for finishing when the water disappears, and the material becomes stiff enough that a firm thumb press leaves only a ¼″ impression. Use an aluminum or magnesium trowel to float the concrete, applying gentle pressure and practice to achieve a smooth finish.

Step 7: Curing and Removing the Forms

Let the concrete cure for at least 24 hours before removing the forms. If the molds were properly prepared, they should come off easily.

At this stage, you can choose to polish or grind the concrete further. An angle grinder equipped with a series of concrete polishing pads is ideal for this purpose. If you opt for dry polishing, ensure adequate ventilation, preferably outdoors. Wet polishing reduces dust but can be messy. Always take appropriate safety precautions when working with concrete dust, as it is harmful to your health.

Step 8: Preparing the Cedar Plank

Cut your cedar plank to the desired length. I chose a length of 5 feet for my bench.

Step 9: Assembling the Bench

Lightly sand and oil the wood to enhance its natural beauty and protect it from the elements. Then, slide the cedar plank into the recesses in the concrete bases. A tight fit is desirable for stability, and a rubber mallet can be helpful during this step.

Congratulations! You have now completed your DIY concrete and cedar bench. Take a seat and admire your handiwork!

Enjoy Your New Outdoor Bench

Here are a few more shots of the finished bench in action:

This project combines the durability of concrete with the natural warmth and beauty of cedar, creating a stunning and functional piece of outdoor furniture. With this guide, you can confidently build your own concrete and cedar bench and add a touch of modern elegance to your outdoor living space.