Water : The worst enemy of your trailer floor

#P.U.R #Waxin #Zig-Zag
Humidity protection Waxin on a wood trailer floor

The transportation industry is constantly looking for ways to reduce its operating costs. What is the solution to achieve this goal? Maximize the useful life of the equipment. The key to obtaining a longer service life of your equipment is to make the right choice of components. For a semi-trailer, good floor is essential for using it and getting the most out of it.

For a trailer floor to last, it is important to protect it from its worst enemy: water.

Water is the number one enemy of hardwood flooring for two reasons:

  • Wood that is too wet will lose its mechanical properties. It will be weaker, less rigid and less hard than dry wood.
  • Repeated periods of being wet and then dry will accelerate the degradation of the wood fibers, reducing the trailer floor’s useful life.

Depending on normal exposure conditions and the different regions of North America where the floor will be used, the moisture content of the wood in a trailer floor will vary between 10% and 18%. If the moisture content is between 10% and 18%, there will be no problems. The floor will be strong and durable for at least 10 years. The problem is that exposure and operating conditions can vary greatly and will inevitably cause the moisture content to rise, at least temporarily, above 20%. This is where the problems begin. Did you know that at 23% or 25%, a hardwood floor will not be stronger than a softwood floor? Above 30%, rot may even appear, regardless of the type of hardwood used. Unfortunately, at 30%, the floor has already lost more than 50% of its strength. Therefore, even if the floor does not rot, it will inevitably break down. These extreme cases are very rare and are more often than not related to problems with the design of the semi-trailer, which does not allow for adequate water flow. These problems can also be related to rugged use in extreme conditions.

Do you want to keep your semi-trailers for 15, 20 years? Do you also want to protect their resale value? You need to protect the areas that are most at risk of being affected: the joints, the top of the floor near the rear doors, and the underside of the floor.

Zig-Zag joints

Close-up picture of Prolam’s Zig-Zag joint design

A trailer floor often has more than 2000 joints. It is therefore essential to choose the best type of joint in the industry to protect your trailers. The hook joint is the worst joint design for semi-trailer floors. Why? Because mechanically, it is not at all effective in distributing the load of pressure when forklifts pass during loading and unloading. Moreover, the hook joint often lets water infiltrate into the floor. The hook joint is the perfect example of the laziness of the manufacturers that use this type of joint for trailer floors. It makes their production process easier; however, for customers, it is the worst joint. At Prolam, we take a different approach: the customer’s needs come first. That’s why we invented the Zig-Zag joint. It is a joint with a double mortise-and-tenon design. Our Zig-Zag joints maximize resistance to forklift stress while minimizing water infiltration. Zig-Zag joints are routinely installed on all our floors at no additional cost to our customers.


The top of a trailer floor near the doors is by far the most exposed area to the elements and the most affected by forklift traffic. To enable the floor to maintain its mechanical properties during its useful life, it must be protected from water. According to USDA studies on water protection of wood, paraffin is by far the most effective product and method compared to other solutions, such as paint and stains, or oils, like linseed oil, which is the least effective.

In house water penetration tests to our hardwood trailer floors

Prolam’s Waxin is a protective treatment that impregnates the wood fibers on the surface of the floor with paraffin. This process allows water to stay on the surface and evaporate more easily. With Waxin, the top of the floor is better protected against repeated cycles of wetting and drying. Because the paraffin is in the wood, not on the wood, even after repeated forklift passes, your floors will still be protected. Two options are available to best suit your needs: Waxin 8, which will protect the first 8 feet at the rear of the trailer, or Waxin 100 for complete protection of the top of your trailer floor.  


The underside of the floor, especially above the wheels, is constantly exposed to the outside elements, such as rain, snow and the products used for road maintenance during the winter. The standard product used by all manufacturers to protect the top of the floor is a simple water-based paint that rarely lasts more than 5 years—and even less above the wheels. That’s why Prolam developed P.U.R for high-quality protection and unmatched durability. P.U.R, which is 11 times more abrasion-resistant than paint, is a polyurethane coating that protects wood from the harsh elements.

Most of our customers use our P.U.R protection because it protects 100% of the underside of their trailer floors. Another very interesting option in terms of cost-benefit is an application of polyurethane located under the wheels, which represents a partial P.U.R treatment.

Our laboratory and road tests clearly demonstrate the benefits of P.U.R protection and its unmatched durability.

Water-based coating to the underside of a competitor’s trailer floor

In conclusion

Water is the worst enemy of trailer floors. It causes them to lose their mechanical properties and shortens their useful life. The solution? Proper protection from Prolam, which has the best waterproofing options in the industry, Waxin, P.U.R and Zig-Zag joints. Many of Prolam’s customers, which own thousands of trailers, use our products year after year and have always been very satisfied.

Prolam is driven by innovation. And our success is driven by the success of our customers.

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