A Quick Guide to Shed Life: What You Need to Know About Vapor Barriers

barn style shed
Spread the love

Sheds are more than just for storage use. You can be creative with your shed. You can use it as a greenhouse, a bar, a kitchen, a work area, a miniature house, or even a movie theater! Before building your desired shed, however, you need to consider a lot of things. One of these is how to make it as sturdy as possible.

To preserve your shed’s life, you need to protect it from water damage, and vapor barriers are key to preventing that. These are sheets of plastic that are non-permeable to water, preventing it from penetrating an area.

Do I need a vapor barrier for my shed?

Your shed’s foundation needs a vapor barrier because water can always come from the ground. Meanwhile, you generally don’t need to place vapor barriers for the walls if your shed is not heated or air-conditioned.

Non-climate controlled sheds typically don’t need vapor barriers because the airflow should remove any locked-in moisture. Even so, you must ensure that the shed has proper ventilation to allow the moist air to escape and prevent rot and mold growth.

If your shed has six or more inches of the airflow underneath it, then it doesn’t need a vapor barrier. Any moisture that sticks underneath your shed will be taken care of by the airflow.

Where should I install a vapor barrier?

While correctly installed vapor barriers protect your shed from water damage, installing it in the wrong place can actually cause more problems. It will make the vapor barrier hold moisture, encouraging rot and growth of mold and mildew. Where you install your vapor barrier will depend on the climate in your area.

For air-conditioned sheds in hot and humid places, it’s best to install the vapor barrier at the exterior side of the walls to prevent moisture from going into the shed. Installing it on the interior will lock moisture inside your shed instead. 

For heated sheds in colder climates, however, it’s the opposite. You need to install the vapor barrier on the inside of the framing to protect your insulation and walls from the warm and humid air inside the shed.

If you’re considering a concrete slab foundation for your shed, you should put down a thick layer of a polyethylene-polyester blend vapor barrier between the ground and the concrete. This helps prevent moisture from entering the shed through the concrete. 

If you’re planning to build your shed on a gravel foundation, a vapor barrier between the ground and the gravel can prevent your foundation from being damaged by the moisture in the ground. Putting some space between the gravel and your shed’s floor can also help protect your shed, as space allows for airflow that can sweep away any moisture buildup.


Building a shed of your own can be fulfilling. To get the most out of your shed, you have to make it withstand any damages that the elements could bring. Knowing when and where to install a vapor barrier for your shed can spare you from making frequent repairs due to water damage.

If you’re looking for the best material for shed interior walls or simply just on the hunt for easy wood shed plans, My Shed Plans is the best place to go. We offer you a wealth of resources for all your shed needs, so browse through our content today!