The Marvin Story

Integrity Windows and Doors is part of the Marvin family of brands. Employing the values and commitment to quality that made Marvin the premier manufacturer of made-to-order windows and doors, Integrity was created to set a new industry standard in performance and durability.

Marvin History

Marvin Windows and Doors is a family owned and operated company. Founded by George Marvin in 1912, his hard work, ingenuity and integrity would become the pillars on which Marvin group of companies would grow. The countless stories of George Marvin's philanthropic work continue to inspire those who carry on the family name.

Under the leadership of George's son, Wm. S. "Bill" Marvin, Marvin Windows and Doors grew from a few dozen employees in the 1950s to more than 4,000 today. Marvin family of companies is proud to be the world's largest made-to-order window and door manufacturer and even prouder of our reputation for quality to excellence in the small town of Warroad in northern Minnesota.

Customers interested in learning the complete history of Marvin group of companies and the Marvin family are invited to WM. S. Marvin Training and Visitor Center in Warroad, Minnesota. Admission is free. For information on tours, contact your Integrity retailer.

Marvin family group photo

Third and fourth generation Marvin family working for the company today

Our Brands

Marvin Windows and Doors has cultivated a worldwide reputation as an industry leader in product innovation, design, and energy efficiency. Bringing you superior value through expert craftsmanship, the highest quality materials and an extraordinary level of service, only Marvin offers unmatched design flexibility and the industry’s most extensive selection of customization options

Learm more about Marvin Windows and Doors at

Integrity Windows and Doors was founded in 1994, with the introduction of Ultrex pultruded fiberglass - a revolutionary new construction material with eight times the strength of vinyl. Today, Integrity is the largest manufactuer of Ultrex pultruded fiberglass products, offering All Ultrex, Wood-Ultrex and IMPACT Products.

Click here to learn more about the Ultrex Advantage.

Infinity offers a full line of replacement windows and patio doors made from low-maintenance Ultrex, and designed with the traditional appearance of wood windows. All Infinity windows are sold as a complete installed package for an enjoyable, hassle-free experience from initial consultation all the way through full-service delivery and installation.

Learn more about Infinity at

Integrity Windows and Doors logo

Integrity Windows and Doors didn’t just join the fiberglass revolution—we pioneered it. In an effort to create a new, low-maintenance, long-lasting window, Marvin created and patented Ultrex pultruded fiberglass. Stronger and more durable than existing fiberglass, vinyl and roll-form aluminum products, Marvin saw this could push window manufacturing in a revolutionary new direction. After extensive testing and work with the Marvin design team, Integrity Windows and Doors featuring Ultrex pultruded fiberglass were introduced in 1994.

By 1996, a new factory was opened in in Fargo, North Dakota, exclusively manufacturing Integrity windows and doors. The continued success of the Integrity led to the construction of another facility in 2004 in Roanoke, Virginia.

Integrity continues to find innovative new ways to incorporate Ultrex. Today we offer All Ultrex, Wood-Ultrex and IMPACT windows and doors. Marvin remains the exclusive proprietor of Ultrex products, using it in their Integrity Windows and Doors and Infinity Replacement Windows brands.

At Integrity, we believe it is essential to live up to our name.

Wm. S. Marvin Training & Visitor Center

There is no better way to experience the rich history, innovations and commitment to excellence of Marvin Companies than a visit to the Wm. S. Marvin Training and Visitor Center. The 6,000 square feet of exhibits include a combination of artifacts and interactive presentations that will wow visitors of all ages.The Visitor Center is open to the public with free admission weekdays from 8 a.m. to 6 p.m. and weekends from 1 to 4 p.m. We also invite you to tour the Marvin manufacturing center to see our Built around you® promise in action.

Wm. S. Marvin Training and Visitor Center in Warroad, Minnesota

Special tours and training sessions are available for trade professionals who work with Marvin and Integrity products. Contact your Integrity retailer to schedule one of these in-depth, eye-opening trips to Warroad.