Poured concrete is one of the most common materials for sidewalk construction. These walks have the advantage of being flat, durable, and attractive. While not as easy to repair as other materials, a concrete walkway will provide years of low-maintenance enjoyment.
There are three ways to install concrete. Precast concrete functions very similar to brick and other forms of masonry walkway, and shall be covered here.
Concrete slab walks are found serving as sidewalks to municipal roads and as other primary walkways or secondary walkways. They are at once the most durable and most difficult to repair. A third option is to pour concrete into molds, casting shapes on-site to have a similar after-effect as precast concrete.
The Pros and Cons of Concrete
Concrete is one of the most popular building materials for primary and secondary walkways. Pouring concrete slab walks is not a job for amateur DIYers due to the complexity, but is feasible if you have some experience. Below are the main advantages and disadvantages of choosing poured concrete over other forms of sidewalk.
Poured concrete is well-loved for its high durability and resistance to erosion. A properly installed concrete slab may last several decades before requiring replacement or repair. There is a high degree of flexibility in materials used for the concrete mixture, as well as the ability to add inlays, texturing, and many other bits of detail as the slab dries.
It also conforms more easily to turns in the walkway without the need to cut or shape the materials first.
Price-wise, concrete slab walks are cost-efficient, with the initial investment averaging between $8 and $10 per square foot and the final product lasting for decades with only minor maintenance needed.
The single biggest problem with concrete occurs when repairs are necessary. Concrete slabs are large, heavy, and prone to cracking or shifting over time. It can also be difficult to build a poured concrete walk, and drying is a slow process that will make the walkway unusable for several days during construction.
Building a Concrete Slab Walk
Laying a sturdy poured concrete walkway takes time and planning. You will want to set aside several days to allow for construction and drying, as well as having temporary alternative paths to any structures being connected.
Step 1: Gathering Materials
You will need a variety of tools and supplies to complete your new walkway, many of which can be borrowed or rented. The amount and types of materials needed may vary based on your particular project and type of utility stone used to make the concrete.
- 1x4x4 wooden boards
- 2×4 board longer than the planned walk’s width
- Concrete float
- Concrete mixture
- Edging trowel
- Geotextile fabric
- Groove trowel
- Tamper (hand or mechanical)
- Thick string or twine
- Wooden stakes
Step 2: Preparation
Begin by moving any potential obstructions along the planned excavation, such as overhanging hedges or plants. Using wooden stakes and string, plot out the path your new walkway will take.
Next, spray or brush lines using non-toxic paint to mark the edges for your excavation, using different colors for plotting close lines. This allows you to differentiate alternative layouts, edging lines, or other variations in the project. Straight walks may also be marked by snapping chalk lines.
Step 3: Excavation
Now you will need to excavate the path. In warmer climates where the soil has decent drainage, nine inches is generally deep enough. However, in an area where the soil doesn’t drain well or freezing is common, a depth of one foot is recommended.
The walkway will generally follow any changes in gradient, although any slopes should always point downward away from the home to aid in drainage.
You can always check the current grade height using either a builder’s level or stakes and string set in undisturbed ground alongside the excavation area.
In some cases, you may choose to make the slabs level and build small retaining walls and steps at intervals, or create some other differentiation between the walk and adjacent ground.
Such modifications are aesthetically pleasing but best left to a professional in most circumstances due to the added difficulty. When adding a border of brick or pre-cut stone, remember to include these in your excavation.
Step 4: Creating the Base
The first step after an excavation is to tamp the ground until it’s firm and flat. Once this is done, you will want to line the trench with geotextile fabric. This material will help prevent organic material or small dirt particles from interfering with your base.
Use it to line the bottom and sides of the trench, creating a two foot overlap at any seams. Excess material at the top may be trimmed off once the work is completed.
Next, pour dampened gravel or a similarly fine-ground utility stone into the trench to a depth of 6-10 inches, leaving 2-4 inches for the actual walk. Measuring the correct amount of water to mix into the gravel may be done by squeezing a handful.
A mixture that is too dry will crumble, while too much moisture will cause seepage under pressure. The correct amount should be damp enough to hold its form after squeezing without shedding excess water.
Step 5: Tamping in Lifts
Whether you are tamping by hand or using a machine, this step must be done in small increments, known as “lifts”. These are merely a measurement of depth to which you compact the base material.
Begin by raking the base material, so it’s more evenly distributed. When tamping by hand, each lift will be about one to two inches, whereas using a mechanical compactor allows for three to four inch lifts.
Work up and down down the length of the walk, overlapping each section and pass by a few inches to ensure even compacting. Make sure to hold a hand tamper vertically so that the entire bottom surface hits the gravel. Even a slight angle may compromise the base.
Step 6: Building a Form
Drive wooden stakes into the ground at four foot intervals just outside of the walk’s planned edges. Screw 1x4x4 boards onto these stakes on the inside edge to create a form for the concrete. As you do this, make sure the tops of the stakes are slightly below the upper edge of your form to make smoothing easier.
You will also want to ensure the boards are plumb and level to avoid problems during pouring and smoothing.
Step 7: Pouring the Concrete
Unless you are renting a mixing truck, you will want to carefully follow the manufacturer’s instructions when mixing the concrete. The finished mix may be transported in buckets or wheelbarrows.
Locate the lowest point of your walkway (or pick one end, if there is no gradient) and begin pouring the concrete. Work your way to the highest point (or other end), and use the back of a garden rake to gently smooth as you go.
Once the form is filled, take a 2×4 and lay it across the walk at your starting point. Drag it along the form to screed, or smooth and level out the concrete. Note that having an extra pair of hands is very useful for this phase. Finish off with concrete floats, dragging them at a slight angle to further smooth the concrete surface.
Step 8: Finishing Touches
After letting the concrete set for an hour or so, take an edging trowel and run it along the form to create a smooth edge and allow for removal of the wood later. Measure and mark every four feet down the length of the walk and place your 2×4 at each of these points, running a groove trowel along the board to create expansion joints.
Finally, gently graze the surface with a broom to add anti-slip texturing.
At this point, you may wish to create inlays, add permanent decorations such as cobbles, or make any other aesthetic touches. Covering the walkway with plastic or tarp will help the concrete cure more evenly and help prevent cracking. After 48 hours, the tarp and form may be removed, and any edging (such as brick borders) may be installed.
Building a Patterned Concrete Walk
You my wish to create a poured concrete walkway that resembles cobblestone, flagstone, or brick. Thankfully, this is no more difficult than creating concrete slabs, and in some cases may even be easier.
Step 1: Beginning the Project
Creating a patterned walkway requires most of the materials used for poured concrete, although it will also require the use of pattern forms. Pavermaker is a popular cobblestone form, while brick and block shapes may be created using a variety of objects or premade forms. You may choose to use dye to tint the concrete, which will dry to a very pale grey, or add color afterwards to the surface.
Note that the cement is easier to work with if it’s a little wetter than normal.
Step 2-6: Variations in the Base
To a large extent, you will perform the same steps as with a regular poured concrete walkway, with a few exceptions:
- You may choose to have the formed concrete above ground level. This means excavating only deep enough for the base material.
- When using a form, you will need to avoid building a frame along curves. This may also mean excavating the curve into a corner to allow for better form placement if the finished walk will be flush with the surrounding ground.
Step 7: Adding the Concrete
Line up the form with the lowest corner of your walkway. Shovel the concrete mixture into the form and smooth the top using your shovel. Once smoothed, gently lift the form away and set it next to the finished blocks to continue your pattern.
Turning the form will allow for variations in the cobbles or brick pattern. You can use a trowel to curve the cobble edges, although many DIYers prefer to use their finger for more control and speed.
Edges are a little more difficult to work with if you are building a cobblestone walk flush with its surroundings. This official Pavermaker video describes how to work around this dilemma using the forms.
Step 8: Finishing Touches
To get a natural stone appearance, you may choose to gently dry brush a small amount of paint onto the surface once it has been sitting for a short time. This not only adds some texture, but creates a more unique appearance between individual concrete cobbles. Allow the concrete to dry for 48 hours under plastic or tarp.
Once dry, pour some jointing sand over the cobbles to fill in the spaces. Be sure to brush the sand completely off your cobbles before misting it down to create a solid seal.
Maintaining Your Concrete Walkways
Concrete may be durable and cheap, but poor maintenance can shorten its lifespan over time. The following maintenance routines will help keep your sidewalk in top shape for years to come.
While removing snow and ice is important for safety, it may be less obvious that keeping your walks clear of snow or dirt can actually help keep your sidewalk healthy. Salting the walk in winter can erode the concrete over time, but it is preferable to the damage caused by ice expansion. Dirt covering the walk can also trap moisture, which will begin to slowly wear away the concrete.
Even small cracks in a concrete walk can spell trouble. Water will seep into these cracks and erode the concrete from within. Repairing cracks or resealing patterned walks every 2-3 years will slow the erosion process significantly.