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What Are the Strongest Shed Floor Materials to Use?

If your concerned about your shed floor not being strong enough to support the load or sinking or rotting, consider using one of these shed floor materials.

Concrete is the strongest floor material to use, but it does have its drawbacks. If you’re going to spend a lot of time in your shed working on projects, concrete can tire your feet fairly quickly.

Add to that the tendency for concrete to absorb moisture from the air and you may have mold and mildew problems, especially if the concrete slab doesn’t have a vapor barrier underneath. Concrete is very easy to keep clean with just a good sweep now and then. It’s also a good base in case you want to add some floor covering on top of the concrete.

Wood plank flooring is also strong and sturdy. It will handle anything your yard machinery will dish out. If you get treated lumber, you won’t have to be so concerned with possible moisture problems in the future. It also has a slight give so that it’s not as hard on your feet as concrete.

What is the Best Material for a Shed Floor?

Concrete is the most durable shed floor. To soften its hardness and stress on your feet if you plan to use your shed as a workshop, you can use linoleum floor covering over it or rubber mats where you in places that you usually stand. This will also help keep your feet from getting cold from the concrete if you spend much time in the shed over the winter. If your not sure if a concrete slab is the right option for you read my article Should I Pour a Concrete Pad for a Shed?

The three most popular choices for shed flooring are tongue and grooved timber planks, oriented strand board or OSB, and plywood.

Timber planks should be rated as pressure treated to exposure class 3. This rating means that the wood can withstand occasional dampness. Using tongue and groove planks ensures that the floor won’t squeak or bounce when moving heavy objects, such as riding mowers or ATV, across them. It also ensures that there will be no crevices that moisture or insects can creep through.

OSB is made of strands and chips of wood, usually quick-growing trees such as southern yellow pine and aspen poplar, with some mixed hardwoods added in. The strands and chips are dried and treated with wax and binders. The strands and chips are arranged in layers each perpendicular to the last.

These layers are then formed into panels under pressure at a high temperature. Plywood and OSB are generally regarded as similar in strength for similar thicknesses. Some are treated to withstand moisture absorption. The one drawback OSB has is that any panel that is cut loses its moisture protection on the cut edges. If those cut edges aren’t treated, they tend to absorb moisture and swell.

Plywood can be made of soft or hardwoods or a mixture. It is made of layers of wood laid perpendicular to each other and bonded with various types of adhesives according to its intended usage. Plywood is graded as to interior or exterior usage, as well as the number of knots or flaws in the outer layers allowed for each grade. Many plywood types can have one grade on one side and another grade on the other. You also need to have the correct joist spacing for maximum strength you can check out my article What Shed Floor Joist Spacing Should I Use? for more information.

Is OSB or Plywood Stronger for a Shed Floor?

OSB is stronger than plywood of the same thickness. It is free of knots and flaws and there is more consistency between the panels. Another benefit is that it is available in large sheets. OSB panels can be made in lengths much longer than plywood, which is usually limited to 10 feet. This is useful if you are installing it in a large shed and will limit the work needed to treat the cut edges.

The drawbacks include the aforementioned moisture absorption of those cut edges that aren’t treated. Sliding items across this flooring such as heavy boxes can cause chips to tear off or leave splinters poking up. There are polyurethane sealers that can combat this tendency. OSB is generally less expensive than plywood, but this can vary with the local market prices and availability. Make sure your installing the plywood flooring in the correct direction, you can read my article What’s the Correct Direction for Installing Plywood? for help.

How Can You Make an Existing Shed Floor Stronger?

If you bought a home with a shed, and you notice that the shed floor is bouncy or squeaky, or just doesn’t seem up to the task, you can make it stronger. You can add plywood to any flooring made of wood products, making sure your screws or nails go through your new plywood, old flooring and into the joists to ensure stability.

However, if your floor has signs of previous or current moisture problems or any rot, the floor needs to be replaced, not covered. If your floor has had moisture problems, the new flooring will absorb moisture from the old flooring underneath, and you’ll still have the same problem.

Besides that, it’s really hard to thoroughly assess any damage moisture may have caused just by looking at it. Once you start removing the old flooring, you’ll probably find more damage than you expected. Any moisture problems need to be addressed first to prevent them from happening again. Find out where the moisture is coming from and do what is needed to keep it out of your shed.

If your flooring seems weak or unstable, you should also check underneath the shed. The framing may be at fault. The joists may be made of smaller than required lumber and/or spaced too far apart. There could also be possible moisture problems and rot in the joists. This should certainly be checked out before adding to or replacing the flooring to see where the problem actually lies. You’ll need to replace any damaged joists or perhaps add more between the existing ones to provide more support.

What are the Cheapest and Strongest Shed Floor Options?

Rustic or utility-grade hardwood flooring is often a good option if you aren’t picky about looks. Some may come with defects and marks. It is strong and less expensive than regular flooring. Many lumber companies and the larger big brand suppliers stock this type of flooring. OSB and plywood are also both less expensive choices and make good flooring as long as you get the right thickness. Both even come in tongue and groove options. Check out your shed flooring options and pricing and you’ll find the right balance for your shed.


The type of shed flooring you use should be based on what you’re going to be using the shed floor and if you’re planning on moving the shed. Concrete is permanent and can support a lot of weight. If the shed is for storing small stuff then plywood is fine.