Why is my Shed Floor Rotting?

Handyman Flooring

Moisture is possibly the biggest enemy of your shed’s floor system. Think of all those spring rain showers, the early morning dew, the summer humidity and melting winter snow. It’s clear that moisture is difficult to avoid, but prolonged exposure could be detrimental to your shed’s durability.

Some shed buyers quickly discover their shed’s flooring may not be as durable as they thought when they made the purchase. They ask “Why is my shed floor rotting?!” The simple answer is that their shed wasn’t built to withstand the moisture that is unavoidable in any backyard.

This is why it’s essential to know how your shed floor is constructed. Your belongings are valuable and need a secure, durable floor that will protect your things. 


If built correctly, your storage unit will be protected from any foreseeable water damage. It will be capable of withstanding the test of time.

There are 3 key construction notes to keep in mind when building or buying a shed.

  • The place where your shed’s floor system meets the ground is at the greatest risk of rotting. 
  • Your storage building should be slightly elevated to allow for better air circulation.
  • For best results, the entire floor frame should be built with weather-resistant materials.

At Cook Portable Warehouses, our floor systems are constructed with pressure treated lumber. This specific type of wood is approved for direct ground contact, making it resistant to decay.


The notched floor skids are in direct contact with the ground and help elevate your building. The entire floor system is made from pressure treated lumber. In our continued search for the best products to make our sheds, we have changed from a plywood flooring to a product called LP ProStruct®. 


This flooring is created with LP’s Treated Wood Strand Technology with SmartGuard® applied to resist fungal decay and termite damage. This scientifically tested flooring also resists warping, splitting and cracking. This isn’t standard OSB, it’s an engineered wood. We also used a variation of this engineered wood as our siding, called LP SmartSide®. Learn more about how this wood is engineered. 

Our construction practices allow us to place a lifetime warranty on all of our portable sheds – both new and pre-owned. This warranty guarantees protection against rot, whether it be from water damage, fungal decay, or even termites! Click here to learn more about our lifetime warranty!

See how we build our sheds from start to finish: 

Looking for more resources to help you buy the best shed possible for your needs? You can send us a private message on Facebook or visit your local dealer!  Plus, here are some great articles that will aid you in your search: 

What Types of Sheds to Avoid

What to Avoid When Buying Pre-Owned Sheds

Avoid These 3 Common Mistakes When Buying A Shed