Addressing Condensation Failures in Windows and Doors.

This Fifth Avenue single-family was designed by the renowned architectural firm Delano & Aldrich. It was completed in the early 1920’s. It stands as a hallmark of refined prewar architecture on Manhattan’s Upper East Side. Delano & Aldrich were known for their classical proportions. Their work had understated elegance. They created many of the city’s most distinguished residential buildings. Each building reflects a deep respect for craftsmanship and material integrity. Overlooking Central Park, this limestone-clad cooperative residence remains one of Fifth Avenue’s enduring treasures. Its historic character and architectural restraint have withstood the test of time.

Building Information

Type of Building: Prewar Cooperative / Landmark Residential
Architect: Delano & Aldrich
Location: Fifth Avenue, New York, NY
Scope Completed: Sash replacements where glass had condensation.

Why the Work Was Needed

The custom wood windows, which were originally made by Zeluck Windows, began showing signs of insulated glazing unit (IGU) failure. Moisture infiltration and gasket deterioration caused persistent condensation between the panes. This created a cloudy appearance and reduced both energy efficiency and overall visual quality.

While the existing mahogany frames remained structurally sound, the low-profile gasket systems—which carry limited warranties—had compromised the sealed glass units. The objective was clear. We needed to restore clarity and performance. We also had to maintain the precise historical proportions required by the Landmarks Preservation Commission (LPC).

The Right Path Windows & Doors Approach

Right Path Windows & Doors was commissioned to replicate and replace the custom mahogany sashes. This was done in exact accordance with the original Zeluck Windows design. They matched every profile, proportion, and joinery method. These sashes are now paired with a far superior glass unit for enhanced longevity and performance.

The Fabrication

Each sash was handcrafted from solid mahogany. It was built to a 2¼” thickness with custom parting beads and glazing stops. The sash also featured 6-over-6 simulated divided lite grids that faithfully reproduced the original aesthetic. The new insulated glazing featured 1-1/8″ Low-E glass with a 20-year warranty. It also included aluminum spacers, providing superior energy efficiency. This setup eliminated the condensation issues that affected the prior low-profile units. In addition, laminated glass was incorporated to further reduce sound transmission, a valuable upgrade for Fifth Avenue living.

The Installation

This project required a white-glove installation. It was executed with precision to protect the surrounding finishes. The aim was to maintain the integrity of the original window frames. The most complex challenge was installing new sashes into existing frames. It involved seamlessly reconnecting them to the traditional weight-and-chain counterbalance system. Additional weights were needed to adjust for the new laminated glass. This adjustment ensured smooth, balanced operation and complete aesthetic continuity.

Why It Matters

This sash replacement demonstrates the value of addressing window condensation through craft-based replication rather than short-term repair. Right Path Windows & Doors replaced the entire sash with upgraded insulated glazing. We delivered clarity, performance, and authenticity. This ensures this Delano & Aldrich landmark continues to define Fifth Avenue’s architectural heritage for generations.

That’s the Right Path Way — restoring history with care, respect, and precision.

Call or text Right Path Windows & Doors at (914) 200 4481