Is FRP Waterproof?

A: Absolutely FRP is waterproof. Just like other building materials, it does have an absorption rate to it, but it’s very minimal compared to wood or something along those lines.

When building structures in environments that encounter a lot of moisture; whether it be some substances or water—corrosion is always a major concern. In these environments, wood will take on a large amount of moisture and warp while metal will corrode. This leads to many problems including hazardous wear, costly repairs, and even serious accident probabilities.

While many substances are corrosive such as oil, acids, and surprisingly—blood; water is the biggest problem. Why? It’s simple; water is used in just about every industrial application in any industry. Whether it’s to clean, to cool, or a result of the environment the facility or structure resides in, water is a common substance.


While water is a necessary substance used in just about every industry to some capacity—it can be damaging. Structures such as wood or metal catwalks, decking, handrails, and stairs can suffer damage that is detrimental to safety. These damages can result in accidents that cause serious injury or death of an employee. That is simply a risk no company wants to take—and with FRP structures in place, they wouldn’t have to.

Water Vs. Wood

Wood is one of the least expensive structural materials in industrial applications but also the most vulnerable to damage. Everything from fire, extreme temperatures, and serious impacts can destroy wood structures with ease. Water, however, is quite a formidable threat to wood as wood is highly absorbent.

Within environments such as oil rigs, waterparks, marinas, and outdoor installations—wood is exposed to moisture and water constantly. The problem is even with treated and sealed wood, water can penetrate and cause serious rot or warping.

Yes, you can seal wood, but that seal does not last forever and it requires frequent re-sealing. If you let the seal go too long without a re-application, water can seep in and do irreparable damage. Water-damaged wood loses its strength, can warp and can come loose from fasteners, or it can rot and fall apart.

Water And Steel

While steel is stronger than wood, it is not without its vulnerabilities and weaknesses. For one, metal is very heavy. This weight means more expensive shipping costs to get structural steel to your job site. It also, in many cases, requires reinforced concrete to handle the weight of steel structures such as catwalks.

Safety is also a major issue with steel. Aside from being a conductive material posing an electrical shock risk, it also is very susceptible to corrosion. Steel can withstand up to thousands of pounds of pressure, yet can be snapped easily with rust.

Since water is corrosive to the iron in steel, it breaks down the material and causes a chemical reaction that results in rust. Wherever rust develops on steel, is where it becomes very weak and brittle. On structures that workers walk on or use for support, such as platforms—rust can be deadly.


FRP has such a low absorption rate that it is deemed waterproof as it’s also unaffected by water because of this. Because FRP is comprised of composite resin and glass fibers there is no iron or any metal in its makeup. This means there is zero chance for rust to develop—and no safety risks because of it. In fact, FRP performs so well in wet conditions that it is used extensively in many “wet” industries such as:

Wastewater Treatment Plant FRP Structures

Wastewater treatment plants are one of the most corrosive environments for metal structures. That is only compounded when you consider just how many metal structures are in an average plant.

You have tank platforms, catwalks, stairs, handrails, ladders and so much more. If all of those are metal, just the maintenance alone supports the switch to FRP products. Inspection, repair, OSHA documentation, and replacement all can drain a lot of man-hours.

With FRP replacing those structures, maintenance goes to virtually nothing, the chance of corrosion goes to zero, and well, you get the idea. It makes financial sense while also mitigating the risk of accidents and injuries.

FRP Oil Rig Structures

When it comes to corrosive environments, offshore oil rigs pose a triple threat to traditional metal structures. You see, the water is corrosive enough as it is, but the salt in the ocean water is also corrosive. Couple that with the crude oil that comes into constant contact with the platforms, stairs, and rails—it’s one harsh combination.

Not only do metal structures such as wellhead platforms, rig ladders, and stairs become slick and dangerous—they also corrode fast. This is expected given the environment where these structures are built but with FRP you can eliminate those problems.

Outfitting offshore oil rigs with FRP is a huge money saver and offers a big boost for safety. Since FRP grating can be textured with non-slip coatings and doesn’t corrode—it bolsters safety from two threats. Corrosion as well as slip and fall accidents from when oil product inadvertently coats the surfaces are the two biggest culprits of accidents on oil rigs.

With FRP’s easy installation and much lighter weight, it makes outfitting offshore oil rigs much easier logistically. Structures can be constructed and installed on-site with regular tools, no heavy equipment, and the product is inexpensive to ship. This is especially important given the desolate locations these rigs are installed at.


If there’s ever an application other than oil rigs that can test the longevity of structural materials it’s a waterpark. Think about it, thousands of people trampling on stairs and decking, sitting on picnic tables, crossing bridges. It will push any traditional building material to its maximum durability with ease. With metal, the constant onslaught of water can lead to corrosion fast and a shortened life cycle. With wood stairs or platforms, there could be rot or even dry rot during the offseason.

This is why you rarely find those two materials at most of your newly constructed waterparks anymore. Older parks are also shifting away from metal and wood materials out of safety and financial concerns. Instead, these parks that must ensure the highest safety standards, rely on FRP. We are talking everything from stairs, handrails, pedestrian bridges, and especially their rides and water attractions.

Within the realm of waterparks, FRP offers a huge long-term financial advantage due to its durability. It’s the same strength as steel but weighs much less and will not corrode. This means their ROI on FRP is going to be far greater than steel or wood. But, it’s not just about savings on materials—the savings come from mitigating the risk of injury due to structural failures.

Lawsuits from even the smallest incidents such as a metal burr cutting a patron’s foot can make a huge impact. Since FRP won’t break down or corrode like metal, there is no chance of that happening or other similar incidents. Those are money-saving features of FRP that many may overlook but definitely can benefit from.


Besides being waterproof, corrosion-resistant, and having a very long life expectancy, FRP also has many other benefits. Industries that normally spend millions on metal structure repair and replacement are looking at FRP because:

  • Low installation costs
  • Better long-term value
  • Fewer risk factors to deal with
  • No exorbitant maintenance costs
  • More durable than steel
  • Fire Resistant


At DEFI Fiberglass we like the reaction we get from clients when we show them how we can transform their business. By switching their stairs, handrails, platforms, and more to FRP, we are saving them a lot of money and risk. Do you want structures that will last with little to no maintenance or replacements and repairs? Contact us today and see how DEFI can help your business operate safely and securely.

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