Or Call Now: 646-401-3121 - Venting and Exhaust Fans
Oil-Fired Generator Chimney Installation
A dedicated stainless steel chimney for an oil-fired generator, routed up the exterior wall and terminated above the roofline.
Commercial Chimney Extension in NYC and Long Island
We raise the height of commercial chimneys and stacks to correct weak draft, meet clearance and code, and stop downdraft caused by surrounding taller buildings. One team scopes, engineers, installs, and warranties the work for property managers, building owners, and contractors across the five boroughs and Long Island.
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Certified and Licensed
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Lifetime Warranty
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48 hr Proposal Turnaround
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Emergency Service 24/7
OVERVIEW
Added Stack Height, Engineered and Documented
A commercial chimney extension increases the vertical height of a stack or flue so it clears the roofline, adjacent structures, and code required termination points. The added height strengthens natural draft, keeps boilers and exhaust equipment venting cleanly, and brings a short or noncompliant stack up to a standard that passes inspection. We size every chimney height extension to your building using measured field data, not assumptions.
As a commercial chimney contractor, we keep one accountable team on the project from the first assessment through warranty registration. We prepare engineered scope and drawings where the work requires them, manage permitting and code documentation, and install in occupied buildings with minimal downtime. When we subcontract into a larger scope, we coordinate directly with general contractors and mechanical contractors, and we back the systems we install with a lifetime warranty.
- 20+ Years in Business
- 1,000+ Projects Completed
- 48 hr Proposal Turnaround
- 24/7 Emergency Service
WHEN YOU NEED IT
When a Commercial Chimney Needs an Extension
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Poor draft from a stack that is too short
A stack that terminates too low cannot pull combustion byproducts up and out reliably. Raising the height increases natural draft and restores steady venting for the appliances tied to it.
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Downdraft from nearby taller buildings
In dense NYC blocks and high rise settings, wind pressure off adjacent towers pushes air back down a stack. Extending the termination point above that pressure zone stops the reversal.
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Clearance or code height requirements
Commercial flues must terminate at the minimum height above the roof and above nearby structures within the governing clearance rules. An extension brings a noncompliant stack up to code so it clears inspection.
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Backventing into occupied spaces
When flue gases spill back into apartments, offices, or common areas, occupants are exposed to smoke and carbon monoxide risk. An extension reestablishes the pressure difference that keeps gases moving out.
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A new or relocated appliance that needs more stack height
A boiler conversion, a capacity increase, or a relocated appliance changes the draft the stack must produce. Added height corrects the shortfall and matches the stack to the new load.
OUR PROCESS
From Field Assessment to Commissioned Stack
01
Assessment and Measurement
We inspect the existing stack, roofline, and surrounding structures, then take field measurements to determine the exact height and configuration your building requires.
02
Engineering and Proposal
We prepare engineered drawings and a fixed scope, return a written proposal within 48 hours, and confirm materials, lead time, and access requirements.
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Permitting and Scheduling
We handle permitting support and code documentation, then schedule the work around tenants and building operations.
04
Installation
We set scaffolding as needed and install the extension in occupied buildings with minimal downtime, coordinating around tenants and daily operations.
05
Testing, Commissioning, and Documentation
We verify draft, test the completed stack, register the lifetime warranty, and issue a certificate of cleanliness and functionality for your records.
COMPLIANCE
Work That Passes Inspection and Closes Violations
PERMITS
Prepared and Submitted
Permitting support and engineered drawings prepared for submission and approval.
CODE
Height and Clearances
Code documentation covering termination height and required clearances above the roof and adjacent structures.
CERTIFICATE
Issued on Completion
Certificate of cleanliness and functionality issued on completion for your compliance and insurance files.
WHY US
Built for Commercial Accountability
One Team From Quote to Warranty
Assessment, engineering, installation, and warranty registration stay with a single team, so responsibility never shifts between vendors.
Draft Correction That Holds
We diagnose the cause of poor draft or downdraft before we size the extension, so the added height solves the problem the first time.
Licensed, Insured, and Credentialed
Documentation for procurement and risk review is ready up front, before work begins.
Occupied Building Experience
We install in live buildings with minimal downtime and coordinate around tenants and operations.
Contractor Ready
We subcontract cleanly for general contractors and mechanical contractors, with clear scope, lead times, and reporting.
48 Hour Proposal Turnaround
A written, engineered proposal fast, with 24/7 emergency service when a stack fails.
WHO WE SERVE
Commercial Properties Across the Region
We extend and correct stacks for the full range of commercial and institutional properties, working directly with owners, property managers, facility engineers, and the contractors who serve them.
- Multi family buildings
- Commercial and office buildings
- Restaurants and kitchens
- Hotels and hospitality
- Industrial buildings
- Hospitals and institutions
- Houses of worship
- Retail and mixed use
Schedule a Free Consultation
Serving Brooklyn, Manhattan, the Bronx, Queens, Staten Island, and Long Island.
OUR WORK
Recent Commercial Extension Projects
- Chimney Rebuild
Complete Chimney Stack Rebuild and Masonry Restoration
A severely deteriorated rooftop chimney stack was dismantled to a sound base and rebuilt in new red brick, with a new crown and a stainless steel cap.
- Chimney Rebuild
Complete Chimney Rebuild, Before and After
A failing chimney with crumbling mortar, damaged brick and a broken crown, fully dismantled and rebuilt with a new concrete crown, cap and weather-sealed base.
REVIEWS
What Our Clients Say
Mike S.
Chimney Professionals did a terrific job cleaning my two wood burning fireplaces in a Manhattan brownstone. They came within one day. Their equipment is state of the art, and it was all done in less than 30 minutes. Everything kept spotless. The price was right too.
1 Mar 2026
M. J.
Not only did they answer right away, they had Rod at my door first thing Monday morning and sourced a hard to find part same day when others could not. They beat every other quote I got and had our system back up and running in under an hour.
27 Oct 2025
Bruce S.
The chimney in my 115 year old brick rowhouse had a badly deteriorated terra cotta lining. Michael gave me a fair price, was punctual, and while spending more time than he expected, stuck to the original price. Kudos to Michael for getting a tricky job done.
2 Nov 2025
Jim S.
Mike and his team are phenomenal. Very quick to respond and schedule and then more importantly, absolute professionals. Deep cleaned the chimney and made sure they cleaned any residual dust around the area.
13 Nov 2025
Ryan L.
Our building needed three new liners for each apartment. They did a great job with the removal and new installation. Mike was very easy to work with, and very responsive with any follow ups.
10 Aug 2025
Donna L.
Chimney Professionals were prompt, professional and neat. We would recommend them to anyone looking to get their fireplaces cleaned. A pleasure to work with.
3 Dec 2025
Alan H.
We asked them to inspect our roof and chimney before an upcoming home inspection. They explained every detail clearly, helped us understand what needed fixing, and even assisted with budgeting.
10 Dec 2025
Baktiar M.
Same day service, quick and efficient. Used drones to check the chimney and provided a report. Definitely recommend.
25 Feb 2025
Kara T.
They were able to come out next day and fix our gas fireplace issue. They listened to all of our concerns and addressed any questions we had while thoroughly explaining the work that needed to be done. The price was fair and upfront.
15 Nov 2024
Brandon G.
Mike set up an appointment for the next day to clean our dryer vent. He maintained good communication the whole time. The technician who arrived was professional and did a thorough job. The price was reasonable too.
23 Aug 2025
FAQ
Commercial Extension Questions
We take field measurements of the existing stack, roofline, and adjacent structures, then size the extension to meet the required termination height and clearances for your building.
Yes. We provide permitting support and engineered drawings, and we deliver the code documentation that inspectors and insurers require.
Yes. We install in live buildings with minimal downtime, set scaffolding as needed, and coordinate around tenants and operations.
In many cases, added height restores the natural draft a boiler stack needs, especially after a conversion or capacity increase. We confirm the cause during assessment before proposing a scope.
Often, yes. Extending the termination point above the pressure zone created by adjacent towers stops the air from reversing back down the stack. We verify the condition on site first.
Yes. We subcontract for general contractors and mechanical contractors with clear scope, lead times, and reporting.
We return an engineered proposal within 48 hours and offer 24/7 emergency service when a stack has failed.
Get Your Commercial Chimney Extension Scoped
Send us your building details and we will assess the stack, size the extension, and return a written proposal within 48 hours. One team from quote through warranty.
MANUFACTURING
Your Extension Is Made and Installed by One Team
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Stainless Steel Pipes
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Chimney Liners
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Custom Caps
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Chase Covers
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Tees, Wyes, and Elbows
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Adapters and Reducers
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Flue Pipes
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Custom Fabrication
Height sections from our own shop, not a distributor queue
Because we manufacture our own UL Listed stainless steel pipe and fittings, the height sections your extension needs come from our own shop rather than a distributor queue. For your project that means the stack is engineered, built, and installed by one team, with materials matched to your existing chimney and the loads it carries.
What that means for your project
- UL Listed stainless steel pipe and custom sections fabricated to the exact height your extension requires
- Components engineered for your existing stack, roofline, and NYC climate loads
- One accountable team from fabrication through installation, with no supplier delays
- Lifetime warranty on the stainless steel components we manufacture, registered on completion
