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Serving homeowners & builders for over 50 years!

Commercial Lumber & Building Supply-logo Celebrate20Years


Millwork moulding Window

Find the perfect mouldings, windows and doors for your remodeling or new construction project at Commercial Lumber & Building Supply. In business since 1960, we have a legacy of supplying only the highest-quality products.


When it comes to windows and doors, we've got all your needs covered - including custom orders. If you need product guidance, rest assured our knowledgeable staff will help you make the correct decisions.

High-quality mouldings and millwork


  • Primed pine

  • MDF (Medium Density Fiberboard)

  • Hardwood moulding

  • Clear pine

  • PVC exterior mouldings

  • Fypon

Exterior doors

  • Fiberglass

  • Wood

  • Steel core


Interior doors

  • Solid core

  • Hollow core

(We will custom order doors to match your specifications!)



  • Doorknobs, handles, hinges

  • Brass

  • Satin-nickel

  • Oil-rubbed bronze

Doors and windows

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Visit us at: 130 Main Street,

Islip, NY 11751

A legacy of offering the best in building supplies


  • Vinyl

  • Wood


Basement windows

  • Vinyl sliders

  • Vinyl hoppers


Velux skylights

  • Fixed systems

  • Manual systems

  • Electric systems

  • Sun Tunnel

  • Pan-flashed skylights

  • Special-order blinds