Frequently Asked Questions

Unlike studios, we don't have a vested interest in selling repairs. We provide unbiased evaluations, ensuring your needs—not a studio's sales agenda—dictate the specifications and decisions.

We oversee every step—from the initial RFP to the final installation. By aligning contractors with precise specifications, we prevent costly mistakes and ensure the project is done correctly, on budget, and on time.

With over 75 years of experience, we ensure your windows are properly valued, documented, and protected—whether for insurance claims, disaster planning, or future preservation.

Photographic documentation creates a permanent visual record. It aids in insurance claims, ensures restoration accuracy, and provides a benchmark for comparing the window's condition before and after intervention.

We provide apples-to-apples comparisons by ensuring every bid matches a consistent specification. This empowers you to choose based on quality and accuracy, not just price.

NSGCG provides several types of professional stained glass USPAP compliant appraisals as well as simple valuations, depending on the needs of the client.

Many stained glass windows—particularly in churches and historic buildings—are significantly underinsured because their value has not been professionally documented.

To put it simply, anyone can do a valuation, but it may not be accurate. An appraisal is performed by an appraiser that adheres to and is compliant with USPAP ethics and standards.

USPAP (Uniform Standards of Professional Appraisal Practice) is the set of ethical and performance standards that govern how appraisals are developed and reported in the United States. It ensures appraisers provide unbiased, credible, and well-documented valuations. USPAP is maintained by The Appraisal Foundation.

Yes. NSGCG operates as an independent stained glass consulting firm, meaning we are not affiliated with any stained glass studio performing restoration work. This is especially important when appraisals are used for insurance claims, legal matters, or estate planning.

Our reports document structural elements—lead matrix, framing, solder joints—and aesthetic conditions like paint. They become a baseline for maintenance and future restoration planning.

Yes, we differentiate natural aging (like patina) from urgent issues such as structural bowing. Our reports specify what needs immediate attention.

As independent consultants, we ensure recommendations align with actual conditions, with no bias toward selling repairs.

We assess more than leadwork—frames, support bars, and the entire installation—ensuring every structural factor is covered.

Condition reports provide documented proof of your window's state. They support appraisals, insurance claims, and valuation by offering a clear baseline.

As owner's representatives, we oversee every phase—verifying materials, techniques, and progress align with your specifications. We ensure consistency with regular oversight.

We mediate any deviations. If changes are proposed, we assess their impact. We either approve them if they align with project integrity or enforce the original specifications to protect your interests.

We vet studios by reviewing past work, glazier skills, and references, and we conduct site visits as needed. Only studios meeting our high standards are recommended.

We conduct periodic studio inspections, verifying that methods and materials match specifications, ensuring quality before reinstallation.

We conduct a final walkthrough, ensuring the installation meets specifications. Any final issues are identified and resolved, ensuring full project completion.

High-resolution images capture cracks, paint loss, and prior repairs, creating a baseline. Restorers use these to accurately match original patterns, colors, and textures.

We use transmitted light (from behind) and reflected light (from the front). This dual method captures color vibrancy, structural elements, and surface detail like paint texture.

We produce archival-quality digital files stored securely and shared with our clients, ensuring they're accessible for future restorations, appraisals, or insurance.

Yes. Close-ups and specialized lighting reveal early signs of lead deterioration and cracking, paint flaking, allowing preventative action before damage worsens.

We provide digital files in widely-used formats such as JPEG and RAW if requested, ensuring compatibility over time. Clients receive secure, cloud-based access.

We follow international conservation standards, researching original artists, studios, and materials. Our specifications preserve original elements, ensuring historically appropriate, reversible interventions.

We assess the lead matrix, glass condition, and historical significance. We intervene minimally, reserving full restoration for severe structural failure.

We factor in humidity, temperature shifts, and wind load. Specifications may include protective glazing, ventilation, or climate-suited materials to protect the window.

We document every step—condition reports, photos, and materials used—ensuring future conservators know the exact work done, supporting long-term preservation.

We specify techniques and materials that can be reversed without damaging the original glass, allowing future conservators to update or improve work if needed.

It shields stained glass from weather, debris, and vandalism, reducing repairs and extending its lifespan.

We specify acrylic, polycarbonates, glass or laminated glass. Acrylic is lightweight, polycarbonate resists impacts, and glass offers clarity and longevity.

When designed properly, it has minimal impact. Low-iron or museum-grade glass ensures clarity, keeping your stained glass vibrant.

No, if properly ventilated. We specify systems with venting to prevent moisture buildup.

Yes, we tailor systems to fit historic or modern architecture, ensuring protection and aesthetics.

Releading replaces only the lead framework, while full historical restoration involves research, documentation, structural analysis, and preservation of original glass and paint.

Research and documentation reveal the window's history, materials, and condition, allowing accurate restoration plans that preserve both artistic and historical integrity.

Yes. We work with architects, engineers, and historians to ensure restoration aligns with both structural needs and historical accuracy.

We conduct a professional condition assessment to determine the best approach for long-term preservation.

Begin with a professional inspection and condition report. We assess the window's condition, create a conservation plan, and assist with specifications, vendors, and project management.