9 Brothers Building Supply is your leading flagstonenatural flagstoneirregular flagstone supply company!

Brentwood Flagstones

9 Brothers Building Supply stocks a variety of Brentwood flagstones. These quality flagstones come from top brands such as MS International, Techo-Bloc, and StoneCraft and are available in many colors. If you are looking for an elegant looking stone for a patio, walkway, or wall cap then visit one of our locations in Brentwood or Riverhead today and see our collection of flagstones!

Stop in or get in touch!

Brentwood Location


1670 Islip Ave. 
Brentwood, NY 11717

Riverhead Location


28 Mill Road
Riverhead, NY 11901


We’ll help you through the process


Forklift & Boom Service

a mini crane service for tight or hard to reach delivery spots!

Delivery Service

with our fleet of ready to haul trucks anywhere on Long Island, NYC & 5 Boroughs

Consult Us

to build your dream backyard, driveway, landscape, pool, or patio!

Delivery across Long Island, NYC, and the 5 boroughs

Construction Site Delivery

Local Pickup

Home Delivery

Contractor & Local Business Deliveries

COVID-19 Essential Businesses New York
COVID-19 Essential Businesses New York

Update 6/17/20

Essentially, we will not be coming into contact with clients.

Our stores are open for business. We are allowing customers inside, but we ask that you please wear a mask - and follow social distancing guidelines. We would love to help.

If you have any questions, please ask. We urge you to visit NY Governor Cuomo’s Issues Guidance on Essential Business List.