November 11, 2025

321 West Sixth Street, Austin, TX

By Alex Gross

 
At 670 feet in height, the tower at 321 West Sixth Street in Austin, Texas, is the second-largest high rise in the city’s central business district. This luxury multiuse building houses corporate offices, retail space, residential units, garage parking, and an impressive, 3,000-square-foot clubhouse with pool deck, indoor/outdoor fitness, gathering and meeting spaces, media room, pet park, and locker-room facilities. In total, the residential wing consists of 370 units with 34 different variations.

For a project of this scale, developer Ryan Companies carefully considered and thoughtfully planned each detail to ensure the project would incorporate all the lofty design requirements while also meeting the construction schedule and staying within budget.

Austin-based The Porter Company was chosen as the mechanical contractor for the project based on their commitment to speed, efficiency, and delivering exceptional results.

When analyzing different plumbing solutions that could have been used on this project, The Porter Company leaned towards PEX.

“PEX, specifically Uponor, is by far the fastest installation that you could have with what codes allow right now,” said Grant Thornhill, superintendent at The Porter Company.

The Porter Company also utilized Uponor Kitting Services for this project. Kitting Services drive high-quality, efficient, installations. All components for each unit are organized ahead of time and conveniently bagged until installation, ensuring the correct number of fittings are used in each unit and nothing is lost along the way.  This correlates to stable material costs for the building.

The Porter Company appreciates the speed and versatility of the Uponor ProPEX^® expansion fitting system paired with Kitting Services to deliver the results that matter. Uponor solutions helped them deliver an on-time completion to the developer with a plumbing system that will last the lifetime of the structure.
 

Project Details 
Austin, Texas  

• 321 West Sixth Street 
• 670-foot luxury residential tower
• 370 units, 34 unique layouts
• Mixed-use building with office, retail, and amenities 

Uponor Products 

• Uponor AquaPEX^® for In-Unit Plumbing  
• ​ProPEX^® expansion fittings and multiport tees
• Uponor Kitting Services (373 kits, 34 variations)
• Technical design support and collaboration