Engineers choose composite decking for boardwalks and pier

The 35-foot-tall observation tower at Wall Springs Park in Pinellas County, Florida, offers stunning views of the park and the Gulf of Mexico beyond. A regional gem, the tower and about 30 feet of ramp leading to it were destroyed by arson on September 11, 2013. In the midst of an arduous 5-year reconstruction project, park engineers realized the boardwalks surrounding the tower and the fishing pier were worn and rotting. They chose to replace the decking with MoistureShield Vantage composite decking for those areas to reduce maintenance and increase longevity. With the Solid Core Difference™  for strength and durability, Vantage has very similar workability to wood so there’s no learning curve.

“The original boardwalks installed in 2002 had begun to deteriorate and were becoming a safety hazard,” says John Linton. P.E., senior engineer, parks engineering and design, for Pinellas County. “We then changed the scope of the tower project to include new decking for the boardwalk and fishing pier so the whole area of the park would be updated and safe by the time the tower reopened to the public.”

APPROVAL FOR MATERIAL

The construction contractor on the project presented MoistureShield Vantage in Cape Cod Gray to the county as an alternative to the three composite materials on their preapproved list. “I reviewed all documentation on the Vantage and found it equal to or better than the others, so we approved it,” says Linton. MoistureShield is a division of Oldcastle APG, a CRH company.

MoistureShield Vantage is an uncapped wood composite board with a matte finish that evokes the look of real hard wood. “The color is consistent throughout the board and it cut just the same as wood—even better because it didn’t splinter when cut,” says Linton. “And, with wood-grain texture on both sides, contractors didn’t have to worry about which side they were flipping up.”

COMPOSITE ADVANTAGE

Additionally, MoistureShield’s Solid Core Difference runs through the entire board to ensure protection without a cap. There’s no need for painting, staining, and yearly repairs and Vantage is completely resistant to moisture, rot, and warping. This was significant in Wall Springs Park because most of the boardwalks are in submerged swamp areas where they receive very little sunlight and are moist most of the day. 

“When we first built the boardwalks, the cost of composite decking was considered astronomical. 

The composite decking material has a wood-grain texture on both sides

Now, we’re finding the pressure-treated wood doesn’t hold up as long as it used to and we’re facing more frequent, costly replacements,” says Linton. “The longevity of the composite, as well as the reduced maintenance needs, have made it much more cost-effective.” Vantage has made the price-point differential, when maintenance costs are considered, almost even with wood over time.

For longer spans required by commercial boardwalks, the 2×6 profile of Vantage was used for the decking. The boardwalks are 6-foot, 9-inches wide with an inside handrail. Linton points out Vantage was the only of the composite products they looked at that offered a 2×8 profile that could be used for the top plates on the railings. The rail system has a 6×6 post and 2×2 rails with galvanized metal mesh inset. “We usually have to miter the post to accommodate a narrower top rail. Since Vantage is 2×8, it covered everything without mitering—saving a lot of time—and we don’t have to worry about citizens getting splinters from the top plate,” he explains. 

PROJECT CHALLENGES

Time was of the essence with this project as the area of the park in which the tower, boardwalks, and pier reside was closed off to the public during the entire project. The community was eager to see it reopen, especially when there were setbacks.

“We found out from the building department that the code had changed a bit since the tower was first built in 2004 and we now needed to have a switchback ramp to be compliant,” Linton says. “We were also working with the insurance company after the fire, so that caused further delays.”

PROJECT SAVINGS

We also saved on the need for fire retardant chemicals and their application. The tower and ADA ramp were constructed of wood sprayed with a fire retardant. The composite boardwalks and pier were not because as linear structures it’s harder for them to burn for long distances and they’d be easier to repair.

As a Certified Arborist®, Linton appreciates the sustainability aspect of Vantage. “Why not recycle and reuse materials if you can? I think it’s great,” he says, adding the product’s longevity also contributes environmental benefit. “If the Vantage lasts as long as it should, I won’t have to replace any of these before I retire.”

SUMMARY

The entire reconstruction project was completed in time for the community to enjoy the park on July 4, 2018. The total cost was $2.3 million, of which the boardwalk and pier comprised $250,000. MoistureShield Vantage offered an attractive, easily workable, and cost-effective alternative to pressure-treated wood for the Wall Springs Park projects. As a result, Linton says “I’m adding MoistureShield to the list of pre-approved products and the park standard is now to use composite decking and top plates.”