Ahwahnee Fourth Floor Balcony Replace TREX Decking Material

Yosemite National Park » Ahwahnee Fourth Floor Balcony Replace TREX Decking Material » Document List

The purpose of the project is to replace the current 1,300 sq. ft. TREX decking on the 4th Floor Balcony (Solarium Deck) at The Ahwahnee with natural rot-resistant wood decking. TREX decking was constructed in rectangular panels (approximately 4′ x 3′) and placed in a pattern on the balcony deck during the 2003-2005 re-roofing project. Since its installation, the TREX composition has broken down and eroded (see photos attached). The deck is becoming unsafe due to deflection in the finish surface. Deteriorating material clogs up the gaps between the slats and makes the drainage system ineffective. Pooling water exceeds the height of the flashing at the walls and leaks into the rooms below.
Although the composition of the original decking material is unknown, the Division of Resources Management and Science advised that a lightweight concrete would most resemble the likely original material, but natural rot-resistant wood decking was an acceptable material.
Several options to correct the decking system were considered. The original TREX vendor is no longer in business. After consulting with the Park Historic Architect, the Delaware North Companies Parks & Resorts at Yosemite proposes to replace the TREX material with ironwood planks, a rot-resistant hardwood.
Finishing the deck with wood panels would allow for easy removal and replacement. It would also provide access to the iron plate below, lest future problems occur.
Scope of Work:
• TREX decking material will be removed and discarded appropriately.
• Drainage systems will be cleared of debris and eroded materials.
• Ironwood deck panels will be constructed (most likely off site) and installed in a checkered pattern on the Solarium Deck (similar to the existing pattern).
• Ironwood planks will be stained a natural color.

Project Goals:
• Correct the deficiencies in TREX decking system to improve water drainage and provide a quality decking system for The Ahwahnee guests.
• Protect the The Ahwahnee National Historic Landmark from deteriorating materials that cause water damage.
Special Considerations:
• In May 2009, routine inspections by the NPS Business and Revenue Management Branch recorded the defective TREX decking system and required DNC to fix the deficiency by August 1, 2009.
• Photo documentation of new deck materials will be submitted to NPS upon completion of project.