Overview
Texas Fifth Wall Roofing (Fifth Wall) was able to solve a set of extremely unique challenges on the Hays County Municipal Center. In addition to a typical single ply membrane system, the job required metal corrugated decking materials on a dome that was a critical part of the design.
As a general rule, domes are seldom included features of construction, and as a result, few designers and installers are very familiar with the challenges and issues that are common with dome roofing systems. Since Fifth Wall had completed successful dome installations in the past, our team was well prepared to minimize risk and deliver a beautiful and functional dome.
This particular dome design incorporated a superstructure consisting of curved beams and columns made out of large pieces of red iron. Over the top of that structure, the design called for a corrugated metal decking.
Challenge One: A Square Peg in a Round Hole
The problem became evident early in the design phase. The deck lay in a straight span between the curved columns except where it deformed over the ring beams. Corrugations are typically used to provide additional stiffening making it difficult to bend the decking in two directions as required by the design specification. While corrugated decking panels can bend and flex along the parallel direction of the corrugations, they could not be curved to assume the spherical shape required in the dome design. According to Hewitt, “…it was a real life version of a square peg in a round hole.”
The Fifth Wall Way
The Fifth Wall team developed a method to provide variable height spacers to secure the sheathing material in the proper location to create a spherical shape starting with a substrate that was not geometrically predictable based on the way it was forced around the ring beams.
Challenge Two: Code Compliance
The solution was going to require a different assembly than what was notated in the design. There was also an issue with the building code regarding how the structure would handle wind uplift standards.
Since the assemblies are very specific in nature, when they go through the code approval process, they are tested based on a very narrowly defined set of components. Because an unconventional set of components were required for the dome structure, the manufacturers’ tests would not be applicable.
The Fifth Wall Way
Fifth Wall need to apply innovation and creativity while bringing together unique technical expertise to solve this issue. This meant collaboration with the design team to develop a constructible solution to make the dome a true spherical shape. This required close examination of all components and parts that the manufacturers’ specified for a tapered panel and then subject it to the testing process as a custom design.
A special “jig” was constructed that was able to rest upon the one reliable elevation relative to a spherical shape so the vertical beams were true and set in the right location. The jig rested upon the vertical beams and then utilized arched metal shapes that were at the correct radius to establish where the target elevation was located. These arches then spanned over the uneven deck substrate giving a target spot to hit in space which allowed the Fifth Wall team to measure between the unknown height of the decking to our known height of the jig.
Next, we subjected the exact combination of products for testing, even though it would be costly, The team was convinced it could successfully pass the tests and demonstrate that Underwriters Laboratories criteria could be met.
Fifth Wall assembled a mock-up of the structure and took it to the lab. The custom designed structured exceeded the standard by 50 percent.
Result
The Hays County Municipal Center is a monument to the Fifth Wall Way™. Featuring a shining metal dome, the 232,000 square foot facility will house ten courtrooms and space for county departments that are currently scattered throughout the area. Texas Fifth Wall was named “Subcontractor of the Month” twice by Balfour Beatty Construction the general contractor on the project. According to Brent Johnson, project manager at Balfour Beatty, “…if they were on the job from the beginning, they would have won more often.”
About Texas Fifth Wall Roofing
Texas Fifth Wall Roofing is an award winning Austin commercial roofing company providing new construction and reroofing installations of single-ply, metal and composite systems. As the region’s largest industrial roofing contractor, our service department offers roof repair and maintenance services for all types of commercial, industrial and retail properties. Forward-thinking responsiveness to customer needs and the firm’s commitment to integrity over the bottom line have established Fifth Wall as a leader in the commercial roofing industry.
We are committed to employing innovative roofing technology and are dedicated to building watertight relationships with each of our clients, suppliers and employees.