Durability

Common Questions

There are a few questions that we’re asked frequently pertaining to the durability of FRP architectural products:

  • How long does FRP last?
  • How durable and damage resistant is FRP?
  • How frequently is maintenance and repair necessary, and what does it entail?

This page serves to address these questions by referencing test results, technical papers, precedents, text agreed to by industry leaders, and commentary from knowledgeable experts as well as owners of FRP products.

General Notes

When FRP is fabricated well, in the right environment to ensure its quality, and used appropriately, FRP can last many decades. When not designed and fabricated properly, deterioration and failure can happen quickly. FRP is often chosen specifically because of its resilience, imperviousness to moisture, and resistance to corrosion. Some testing has been done and is available, although since most of the use of FRP since its invention has been in non-architectural industries, such is the focus of much of the testing. Some examples of architectural FRP that has been in service for several decades, or is being used in extreme environments help illustrate its appropriateness for exterior facades.

From the ACMA Guidelines

The American Composites Manufacturer’s Association publishes Guidelines and Recommended Practices for Fiber Reinforced Polymer (FRP) Architectural Products which includes a section on the topic of durability and longevity. Section 3.7 “Servicability, Durability, and Long Term Effects” provides a thorough summary of durability considerations.

Accelerated Aging

We have had accelerated aging tests performed on our products demonstrating little color change after 2000 hours of UV exposure. Most recently, such testing was done in November 2014 with the Fireblock gelcoat we used on the SF MoMA facade project demonstrating an average delta-E of 1. Test report can be found here.

accelerated aging

Image: Accelerated aging coupons of a polyester polymer concrete test with control samples on bottom. Kreysler & Associates Kastone finish at 2500 hours QUV exposure. (Edge discoloration due to test apparatus clamp and should be disregarded)

Comparison to Other Materials

Glass-fiber reinforced cement (GFRC)  has been around since the late 1960’s and is therefore relatively newer than FRP which has been in far more severe service in much more extreme environments since the 1940’s. Conventional GFRC absorbs moisture which is a catalyst for deterioration for most materials, especially in freeze-thaw environments. FRP for all intents and purposes does not absorb any moisture. This is why FRP is useful in applications such as bridge decks, boat hulls, and saltwater fish tanks.

Metal corrodes. The Monterey Bay Aquarium has switched away from using even stainless steel in favor of FRP. The risks are not much different in architectural applications where exposure is high.

Examples

St Joseph’s Cathedral, San Jose

Our work involved replacing the white ribs on the domes with FRP.

cathedral 1989cathedral 2008

Images above of the cathedral in 1989 and 2008. Tony Mirenda, President and CEO of TBI Construction recently reported:

“Hi Bill. Here’s an aerial shot comparison from 1989, two years after installation as compared to a photo taken just a few weeks ago.  As I mentioned to you, the durability and beauty of your product over 20 years is remarkable.  They have not done a thing to it.  And every time it rains, it cleans the product to where it looks as if it is brand new.  From a flexibility standpoint, I was equally impressed by the ease of handling and installing the product given the warped 100 year old shape of the structure we needed to mount it to.  And the strength of the product was superior to any precast options we explored.”

San Francisco Museum of Modern Art

sfmoma

This is currently (in 2015) the largest application of composites on the facade of a highrise building in the US. To everyone’s surprise, when trying to demolish the performance mockup, the ironworkers couldn’t come close to doing any structural damage to the panels with a sledgehammer.

sledgehammer

If a panel were to get damaged, we prepared a video to demonstrate a method of repairing the polymer concrete finish which can be done easily with equipment from a hardware catalog. Such an invisible repair would be extremely difficult on a panel made of concrete or metal.

repair

Halley VI Research Station

This mobile research base, stationed in the Arctic copes in one of the most extreme natural environments. ENR Magazine featured this project here.

More examples of architectural composites can be found among the projects on our website and at compositesandarchitecture.com.

Additional Technical Information and Reports

Combined effects of saline solution and moist concrete on long-term durability
of GFRP reinforcing bars

Accelerated and Natural Weathering of GFRP Bars

The ACMA hosts compositeslab.com with a brief section on durability.

If you have any questions about durability of FRP, or FRP in general, please feel free to reach out to us at 707-552-3500 or info@kreysler.com.