Making a sandbox is unbelievably easy, but there’s a tricky part. Several DIY guides stop at making a wooden frame and placing it on the ground.
Personal experience shows that this comes with a host of problematic issues though. That’s why we often hear the question; what should you put under a sandbox?
That’s exactly what we’ll discuss next in detail.
Does a Sandbox Need a Bottom?
In most cases, yes, a sandbox needs a bottom. This varies from a flimsy layer of landscape fabric to a sturdy wooden base.
The material you’d need to use for the base of the sandbox depends on the type of sandbox you have, and the location where you intend to place it.
Where Do you Plan to Install the Sandbox?
People install sandboxes in one of the following places:
- On the concrete ground of the patio
- On the wooden floor of the deck
- On a brick base outdoors
- On the grass
- In a pit dug into the grass
Placing a wooden frame on a hard floor, like concrete or brick, is the easiest type of installation. The problem is that the sand often pushes the frame upwards, and escapes into the ground.
Additionally, after a little while, the frame might lose its rigidity. In the absence of extra support from the base, the sides come off in disarray. Adding a wooden base improves the properties of the sandbox immensely.
Placing the frame on grass suffers from all the above issues, but there’s more. When there’s no base in the sandbox, insects, weeds, and dirt have full access to the play sand. Which makes the sandbox unsafe for children.
A dug-in sandbox wouldn’t have the structural issues that on-ground installations have. But the absence of the base is still problematic when it comes to letting in unwanted crawlers and dirt. In this case, a landscape fabric or tarp would straighten things out.
Why Is a Sandbox Bottom Necessary?
Having a sandbox bottom is more than an aesthetic addition. It’s necessary for the following reasons:
- It keeps the sandbox frame structurally sound
- It contains the play sand nicely inside the sandbox
- It prevents insects from getting inside the play sand
- It eliminates the growth of sand or weeds inside the sand
- It keeps the dirt layer from mixing with the play sand
What’s the Best Material to Put Under a Sandbox?
The location of your sandbox dictates the best material to use for its bottom lining or support. It’s preferable to use a combination of wood and landscape fabric if you’d place the sandbox on a solid floor.
A sturdy wooden base isn’t necessary for dug-in sandboxes, so a landscape fabric alone would be sufficient.
Here are some of the best materials to put under a sandbox.
1 – Cedarwood
This type of wood is humidity and weather resistant, which makes it perfect for this outdoor installation. It’s the least likely material to rot or warp.
Cedarwood needs the expertise of professional workers though. This adds to the cost and complexity of the installation.
2 – Plywood Sheet
Plywood is a budget-friendly material that’s quite easy to work with. It’s great for lining dug-in sandboxes, as it keeps the dirt or grass layer completely separated from the play sand.
It’s also a great choice as a sturdy bottom on a concrete or brick floor. It would keep the sand from escaping in the spaces under the frame. It would also maintain the shape of the sandbox and keep it from warping.
You’d need to drill a few holes in the plywood for drainage, and then add a landscape fabric lining to prevent insects from getting into the sand.
3 – Pressure Treated Lumbar
This is another option for a solid wood base. This material is versatile and easy to procure. You should just make sure that the finish is suitable for children’s furniture. The finish should be well-polished and weather resistant.
Pressure-treated wood can be a bit problematic though if it’s subjected to excessive humidity. It tends to rot, which should be avoided in children’s spaces. It also might warp and lose its straight edges if it becomes wet.
4 – 2×4 Wood Boards
These are the most common materials used in sandbox bases, especially if you plan to DIY the sandbox. They’re budget-friendly, lightweight, easy to screw in place, and sturdy. On top of that, they give plenty of support to the sandbox frame.
The spaces between the boards facilitate drainage, so you wouldn’t need to drill any holes there. This feature becomes a bug though if you pour the sand directly over this base. The tiny grains would sift right through the gaps.
It’s essential here to line this base with landscape fabric or a perforated tarp. That should provide the required insulation to keep the play sand in.
The type of finish you’d add to the boards matters. A weather-resistant coat should extend its lifespan, and keep its wear and tear to a minimum.
5 – Landscape fabric
This is a perfect lining for any sandbox. It keeps the sand in, and the insects out. At the same time, it drains any excess water with no trouble at all.
The drawback of using landscape fabric is that it’s not too durable. After some time, you’d need to replace the worn-out fabric. It’s also prone to get cut or torn by the kids’ toys.
This fabric is great for containing the play sand, but it doesn’t offer extra support to the sandbox frame.
Thus, you can use it on its own for a dug-in sandbox, but you’d need to use a wooden base together with the landscape fabric for any above-ground installation.
6 – Tarp or Plastic
The next best thing to use after landscape fabric is a tarp. It’s durable, readily available, and quite easy to handle.
Tarp wouldn’t drain excess water though, so you’d need to drill some holes into this material. It’s also prone to cuts and tears.
Plastic is a staple in every household. So if you can’t find any other material, this would always be handy. Remember to drill some holes here too, and change the plastic routinely.
Putting a protective layer under a sandbox is essential to keep all kinds of crawlers or weeds away from the kids’ play sand. As a minimum, you can cover the bottom part with landscaping fabric, but adding a more robust base would be perfect.
Another equally important addition is a cover for the sandbox. Little animals are known to poop and pee in the sand. They could also bury their food in there. You would certainly want to eliminate such possibilities, and that’s why installing a cover is a marvelous idea.
Ben has a bachelor’s degree in construction engineering. When not constructing or remodeling X-Ray Rooms, Cardiovascular Labs, and Pharmacies, you can find him at home with wife and two daughters. Outside of family, He loves grilling and barbequing on his Big Green Egg and Blackstone Griddle, as well as working on projects around the house.
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