How to Keep Ground Moisture From Ruining Your Industrial Floor

Typically, conversations about waterproof flooring begin with the assumption that liquid is spilling onto the surface of the floor. But if your industrial facility is near a waterway, coast, or underground aquifer, your moisture problems may be coming up from underneath.

If you find water mysteriously appearing on the floor, and you're sure nothing is leaking or spilling, it's time to consider the possibility it may be coming up from under the floor.

Seeping water is, unfortunately, a more complicated issue than surface water. Unlike water that sits on the surface, you can’t mop up or wipe away seepage – it just keeps coming back.


The best time to address water seepage is at the time of construction. If you are building in an area near a water source, have your site engineer test the site to determine if moisture in the soil is going to be a problem. Then you can be proactive about building your facility to be water resistant from the bottom up.

One possible solution to building in wet soil is a foundational waterproofing system that involves a primer and waterproofing layer laid under the slab. You may also consider placing a waterproofing layer between the slab and the floor covering. Because this waterproofing layer is both important and delicate, choose a thick, hard covering to protect it from damage.


Whether you are building in new or existing construction, before an industrial floor covering is laid the slab must be fully cured and checked for moisture levels. This is even more important when you know you are building in an area with high levels of ground moisture. A subfloor with too much moisture will not bond properly with either a coating or with a tile adhesive. The slab should have no more than 3 percent moisture for a thinset tile installation and no more than 7 percent moisture for a mudbed installation.

For a flooring system to work, all the elements must be in harmony with one another. This can be challenging when the components come from different manufacturers, which is one reason a quality installer is so important. For example, we once visited a customer complaining their industrial floor was failing. They had used a waterproofing membrane approved for residential, commercial, and industrial applications. Unfortunately, they had paired it with the mortar recommended for residential construction, which was not heavy-duty enough for industrial use.

There is no such thing as a 100 percent waterproof floor, and for good reason. A floor covering that is completely impermeable sounds like a good idea because it keeps all surface liquid from reaching the slab. But it also prevents moisture in the subfloor from evaporating. Moisture vapor transmission barriers keep most vapors from moving within the specific product limits.



example diagram of a Koster waterproofing system

Image of a multi-part foundation waterproofing system,