Welcome to Wellesley Island Building Supply

Wellesley Island Building Supply is located in the beautiful Thousand Islands Region on the St. Lawrence River.

  • Conveniently accessible off Route 81.
  • Our Marvin Design Gallery features full-size window and door displays in home-like settings. 
  • The Wellesley Island knowledgeable and dedicated sales staff will assist you with any project! 
  • Choose Wellesley Island for commercial to residential and new construction to remodeling.

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Scenic Doors What's New

Let the outdoors in with Marvin Scenic Doors

If you're searching for a way to connect your open, interior floor plan with your spacious, exterior living area, Marvin can help you realize your vision with Scenic Doors. Take a look at these FREE, informative brochures that provide easy-to-understand information and creative suggestions for your project. Download your FREE brochures now!

BUILDERS VOTED: BEST IN QUALITY

Each year, BUILDER Magazine asks professionals to weigh in on their brands of choice, from those they recognize and those they use to those they trust to perform when they need them the most. This year, Marvin and Integrity led once again in quality, and Integrity was voted the brand in its category that builders used the most.

Integrity All Ultrex Dark Interior Casement
Introducing All Ultrex Interior Colors

MODERN STYLE.  MODERN PERFORMANCE.

Ultrex pultruded fiberglass, an innovative material Marvin created over 20 years ago.

One of the first premium composites on the market.  Highly durable, strong as steel, and extremely reliable and resistant to expansion and contraction, Ultrex poltruded FIBERGLASS performs as well years after installation as it does on day one.  Now, you can have Bronze or Ebony interior color finishes on All-Ultrex windows AND patio doors!  Maintain the strength and durability of Ultrex with finishes relevant to today's design trends.  Get the performance you need, with the look you want.

Tom Silva for Marvin windows
Proud Sponsor of Award-Winning PBS Television Show “This Old House”

Returning for the 2018 Season!

This Old House Marvin Sponsorship

Through our partnership, more than 50 handcrafted Marvin windows will be installed during this season’s ambitious update of the Arlington House, an early English-style Arts and Crafts home built in 1909 in Arlington, Mass. As the project unfolds, the beloved “This Old House” cast – Kevin O’Connor, Norm Abram, Roger Cook, Richard Trethewey and Tom Silva – walks viewers through an extensive renovation and remodel using carefully selected materials and products, like the Marvin Next Generation Ultimate Double Hung window, honoring the history of the home while incorporating modern design touches and amenities. Check your local listings (PBS) for showtimes to watch the project come to life.

Free Estimate

Choosing new windows and doors can be overwhelming. 

Let our experienced staff help guide you. 

We have everything you need to make your remodeling, replacement, or new construction project easy from start to finish. Our experts can help guide you through even the toughest projects with a FREE, no obligation, estimate.  With a diverse range of product options available, we can help you imagine possibilities you may not have thought of.  Simply contact us for more information.

Tradition that never goes out of style

Timeless.

The double hung window has been a prominent feature in American architecture for centuries.  So have we.

At Marvin® Windows and Doors, it is part of our heritage of providing industry-leading products, and quality windows and doors for the American home. We are proud to make an American classic, handcrafted in America. With advancements in engineering the Marvin Ultimate Double Hung window now integrates a classic look with state-of-the-art durability, versatility and ease of use.

  • Smooth operation, 
  • Tilt-in wash mode convenience  
  • Extensive and LARGE size, 
  • Wide variety of shape options
  • Interior pre-finish stain options 
  • Best exterior finish available
  • Superior aesthetics

This is the perfect window for remodeling, replacement, historic renovation or new construction projects.  We should know, we've been perfecting this for over 100 years.

Marvin Scenic bi-fold door
Wide Open Possibilities

Indoor Outdoor Living Awaits.

Marvin Scenic Doors!

There's a magnificent vista on the horizon. You want to knock down a wall to turn an ordinary room into an extraordinary one and redefine your family room to include indoor and outdoor living spaces. And after all that, you don't want anything to stand between you and your view. That's why Marvin designed a line of Scenic Doors.

  • Marvin Ultimate Lift and Slide door
  • Marvin Clad or all wood Bi-Fold doors 
  • Marvin Ultimate Clad Multi-Slide doors

All Marvin scenic doors are available in stunningly large sizes and numerous panel configurations, they allow for a seamless transition from the exterior to the interior of your home. Marvin's industry-exclusive hardware virtually disappears, giving you an incredibly clean and unobstructed view with simple, effortless operation.

The advantages of working with a Marvin Dealer

Why partner with a Marvin dealer?

Expert advise.  Highest quality products.

Whether you're building a new home, remodeling or making home improvements, we understand that choosing windows and doors can be a big decision.  The options can be overwhelming!

  • Product lines/material choices
  • Energy-efficient glazing
  • Hardware finishes
  • Clad colors 
  • Grid options (ADL, SDL, GBG)
  • Sizing/Measuring
  • Shade options

Fortunately, our Marvin experts will walk you through the plethera of options, asking the right questions to help you make the right choices for your project.  

Ultrex kid standing on fiberglass
Integrity: 20+ Years of Residential Remodeling and Replacement Experience

Integrity products can help with every unique project requirement. 

Pioneered over 20 years ago by Marvin Windows and Doors, Integrity has two distinctive series; All Ultrex® and Wood-Ultrex®. 

What makes Integrity Ultrex® Superior to other products?

  • Strength.  Ultrex® is 8x Stronger than Vinyl and 3x Stronger than Fibrex for less frame and more daylight for your rough openings.
  • Finish.  Integrity has the best finish available for no chalking, fading and long lasting dark colors.
  • Performance.  Fiberglass products have 83% LESS expansion and contraction for long lasting performance and virtually no seal failures.

Integrity products offer the sizing, performance, and configuration capabilities to meet your needs.  Contact your local dealer to get started, their knowledgeable experts can guide you through even the toughest projects.