We'd love to hear from you!

Please contact us with any questions via phone, email, or fill out the form below and we will respond right away.


Gary Duff, President 

Adam Duff, Vice President  

Eric Duff, Vice President


Name *
Phone *


487 Furrows Road
Holbrook, NY 11741


Areas we serve:
Long Island from the Hamptons to Great Neck, including:  Huntington, Dix Hills, Nissequogue, Stony Brook, Setauket, Port Jefferson, Manhassett, Syosset, Old Westbury, Port Washington, Sag Harbor, South Hampton, Oyster Bay, & Babylon

Top authorized unilock contractor in Long Island, NY
Techo pro Old Westbury NY - leading techo-pro contractor in Long Island, NY


  • What can I say, you did it again. For the past two years of living in this house, we never felt the way we do now. I believe the phrase is ‘at home’. Thank you so much for planning out a piece of paradise for us. We cannot get over the transformation. Words can’t express our gratitude. Best wishes to you and your staff, as well as continued success to your company
    — Jim and MaryAnn B.

  • Sorry this thank you comes a few weeks late but we were so happy to see you took care of those few things so now our pool is back to perfect. We are having an awesome season… the pool is fantastic!
    — - Christina H.

  • Thank you for doing such a wonderful job! This entire experience was a complete pleasure- thanks to you and your crew. Andy and I can’t THANK YOU enough FOR EVERYTHING! You have surpassed our every expectation. P.S. Andy is still outside admiring your work, I guess your work is coming before me- you were right!”
    — Joanne O.

  • Just wanted to send you a note letting you know how grateful I am for the amazing job you did on my home. I feel so much happier and proud to live her now. It was amazing how fast you transformed my home. I can never thank you enough!” “P.S. My father came by to see and he said when he walked in the back, he thought he was at the wrong house. But he loved it and was also shocked!
    — Diane

  • It is rare today to work with a group of people that are not only the best at what they do, but also genuine, sincere and just plain nice. So, from Gina, Anna, Frankie and I, thank you for a wonderful yard which we will enjoy for many years. You are the best.
    — Frank L.

  • I wanted to thank you for being such a good friend and for making our little piece of Earth a beautiful place. We couldn’t have done it without your help. We wish you all the best of luck and well deserved success in your beautiful new building
    — Tom and Josephine V

  • Please accept this small token of our great appreciation for your extreme generosity. We absolutely love the porch and the stones made a tremendous difference. We were amazed that it was the exact amount we needed!
    — Dina

  • Just wanted to say thanks! The stone on the porch came out beautiful! As always, the men did a great job!
    — Dana S.

  • My contractor left me high and dry… permits were expiring… Gary Duff Designs had my entire project done with time to spare.
    — L.S. (Jericho)