Business Details
46 Years
experience
Emergency
services
Your Trusted Partner for Commercial Roofing Solutions
At GC Roofing, we have dedicated ourselves to excellence in commercial and industrial roofing solutions since 1980. Our mission centers on delivering superior craftsmanship, innovative roofing systems, and unwavering commitment to client satisfaction across California. With over four decades of experience, we specialize in inspections, installations, reroofing, repairs, and preventive maintenance, prioritizing energy-efficient and durable solutions tailored to each client's needs. Our team invests heavily in ongoing training and cutting-edge technology, ensuring we remain at the forefront of the roofing industry. Founded by Gerry and Carol Thiesen, our company has evolved from a small family operation into a trusted leader in commercial roofing, serving diverse sectors including healthcare, hospitality, and agriculture.We pride ourselves on community engagement, employee development, and sustainable practices that benefit both clients and the environment. Our proprietary bidding program and partnerships with industry-leading material providers like Polyglass and IB Roof Systems enable us to deliver cost-effective, long-lasting solutions with warranties up to 30 years. From emergency leak repairs to large-scale metal roof restorations, we approach every project with precision and integrity. Our leadership team combines second-generation expertise with modern business acumen, ensuring GC Roofing remains a reliable partner for all commercial roofing needs while maintaining the family values established at our founding.
Services
Metal Roof Restoration
Elastomeric Coating
Single-Ply Roofing
Preventive Maintenance
Emergency Repairs
Details
- Year established: 1980
Highlights and features
- We offer 45+ years of specialized commercial roofing expertise
- Our energy-efficient systems reduce cooling costs by up to 30%
- We provide 30-year material warranties on select roofing systems
- Our team offers 24/7 emergency leak repair services
- We combine family values with proprietary bidding technology
What people say
Professional team
Timely communication
Thorough reports
Energy-efficient solutions
Excellent workmanship
Services
Metal Roof Restoration
Our metal roof restoration system inhibits rust, stops leaks, and provides energy-efficient finishes. The process strengthens seams with fabric reinforcement, seals fasteners, and applies premium coatings that extend roof life while reducing cooling costs by up to 30%. This solution preserves existing metal roofs without replacement.
Elastomeric Coating
This liquid-applied system extends roof life with a reflective, energy-saving white coating. Designed for EPDM, PVC, and concrete roofs, it reflects solar heat to reduce cooling costs while providing leak-resistant protection with available 10-year warranties based on roof condition.
Single-Ply Roofing
Our IB Roof Systems membranes offer durable PVC solutions with polyester or fiberglass reinforcements. Available in 50-80 mil thicknesses, these systems suit various substrates and climates with warranties up to 30 years, featuring easy installation and energy-efficient performance.
Preventive Maintenance
Regular inspections and proactive care prevent costly repairs by addressing debris accumulation, flashing issues, and wear points. Our program ensures commercial roofs maintain optimal performance through scheduled check-ups and timely interventions.
Emergency Repairs
We provide 24/7 response for urgent roof leaks and storm damage. Our team rapidly inspects, identifies failure points, and implements permanent fixes to protect commercial properties from water intrusion and structural damage.
People
Joshua Thiesen
CEO / Contractor
Second-generation roofing expert with decades of field experience, specializing in project evaluation and fair proposal development. Demonstrates servant leadership while ensuring quality installations that meet client needs.
Brandy Thiesen
CFO / Human Resources
Financial leader with Doctorate in Business Administration, managing company finances and employee relations. Focuses on professional development and maintaining organizational stability through compassionate HR practices.
Kristen Patterson
COO / Marketing Director
15+ years property management professional with Disney leadership experience. Drives growth through organized project management and strategic marketing initiatives that enhance client communication and service delivery.
Donna Buller
Administrative Assistant to the CFO
Brings healthcare administrative expertise to financial operations, maintaining accurate records and customer databases while supporting team coordination and client information accessibility.
Johnny Kawel
Training Manager
Specializes in workforce development, ensuring team members receive ongoing technical training and safety certifications to maintain industry-leading service standards and operational excellence.
Questions
What commercial roofing services do you offer?
We specialize in metal roof restoration, elastomeric coatings, single-ply systems, preventive maintenance, and emergency repairs for commercial properties.
Do you provide warranties on roofing systems?
Yes, we offer up to 30-year material warranties on select systems from partners like IB Roof Systems and Polyglass.
Are your services energy-efficient?
Our reflective roof coatings can reduce cooling costs by up to 30% while meeting ENERGY STAR requirements.
Do you handle emergency roof leaks?
We provide 24/7 emergency response for roof leaks with rapid inspection and repair services.
What areas do you serve?
We operate throughout California, including Fresno, San Diego, Sanger, and Lancaster regions.
