About National Stained Glass Consulting Group
Over 30 years of real-world, hands-on stained glass expertise — working exclusively for you.
Karl Erickson
Founder & Principal Consultant
Karl Erickson didn't learn stained glass from a textbook. He learned it with his hands — cutting glass, leading panels, soldering joints, and restoring century-old windows from scaffolding 40 feet in the air.
After more than 30 years working as a craftsman, studio restorer, and on-site project manager, Karl founded NSGCG to provide something the industry desperately needed: truly independent consulting and appraisals — free from studio conflicts of interest.
Today, Karl leads a team with over 75 years of combined experience, serving churches, institutions, collectors, and architects across the continental United States.
From Craftsman to Trusted Advisor
Three decades of hands-on experience inform every appraisal, inspection, and recommendation we deliver.
Stained Glass Craftsman
Karl began his career at the bench — cutting glass, painting details, leading panels, and learning the centuries-old art of stained glass from the ground up. This deep, hands-on foundation gives him an understanding of materials and techniques that no classroom can replicate.
Studio Restoration & Conservation
Karl advanced into studio restoration, working on historic and architecturally significant stained glass windows — including pieces by renowned studios. He developed expertise in condition assessment, historically accurate repair techniques, and conservation methodology.
Project Management & Oversight
Managing complex stained glass projects on-site — coordinating contractors, architects, and building committees — Karl mastered the operational side of preservation. From specifications to walkthroughs, he ensured every project was completed right.
Founding NSGCG
Recognizing that building owners deserved independent, unbiased guidance, Karl founded the National Stained Glass Consulting Group. Free from studio ties, NSGCG provides honest appraisals, inspections, and consulting that serves the owner's interest — and no one else's.
Why Clients Trust NSGCG
Published Author
Karl has authored and contributed to multiple publications in the stained glass field, sharing expertise with the broader industry.
Publication titles to be added
Professional Affiliations
NSGCG maintains active memberships and affiliations with recognized industry organizations.
Affiliation details to be added
$1M Liability Coverage
Every project is backed by $1,000,000 in general liability insurance — protecting you and your organization with professional-grade security.
Nationwide Service
Based in the Midwest with reach across all 48 continental states. Offices in Minnesota and Maryland provide broad geographic coverage.
5-Star Google Reviews
Consistently rated 5 stars by churches, collectors, architects, and institutions. Our clients trust us — and they tell others about it.
Trusted by Institutions
Churches, synagogues, schools, historic buildings, and major organizations rely on NSGCG for honest, defensible evaluations and specifications.
Our Approach: Simple, Honest, Thorough
Every engagement follows a clear process designed to give you confidence and clarity.
Conversation
Tell us about your windows and goals. No pressure, no obligation. We listen first.
Evaluation
We inspect, document, and assess your stained glass with meticulous, professional care.
Report
You receive a comprehensive, defensible report in clear, plain language. No jargon, no confusion.
Guidance
We walk you through findings and recommendations, and remain available for follow-up questions.
What Clients Say About Karl
Karl was fantastic with providing the history and how my stained glass windows were made. He also gave me great ideas to conserve and to get the best value on them. I highly recommend Karl and NSGCG on any of your inquiries and stained glass needs. Thank you Karl!
We are remodeling our home and weren't sure if there was any value to the existing stained glass windows – so we went looking for an expert. Karl at National Stained Glass Consulting Group fit the bill. Karl advised us appropriately, and his expertise and input were very much appreciated. We would highly recommend Karl for your stained glass consulting needs.
Outstanding expertise! The owner of NSGCG Karl Erickson was masterful in his analysis of just a few photos I sent to him. He gave me meticulous details about the glass, lead, and solder used in my stained glass window from 1911. He was even able to give me a very well educated guess as to who made it. Karl is quite prompt, with a very reasonable fee. I highly recommend his services.
I'd like to thank Karl at NSGCG for taking time from his busy day to help me identify the origin and determine the value of my stained glass pieces. His efforts far exceeded anyone else's that I had tried to contact concerning the matter. Very professional, very helpful, and very much appreciated!