Commercial Metal Roofing Service

If your existing roof failed this year, do you have a clear plan for a metal replacement that won’t shut down your operations? TWI Roofing provides full-scope commercial metal roofing installation across Nassau County, NY-from new construction standing seam systems to retrofit applications over aging flat roofs. We’re not just ordering panels; our service covers engineering, code compliance, operational phasing, and the kind of leak-free detailing that protects revenue and tenants through wind-driven rain and coastal conditions. This page outlines the metal systems we install, our step-by-step process, how we design for Nassau County’s wind zones and salt air, and how we stage work to keep your building occupied and productive.

Commercial Metal Roofing Systems We Install

Structural Standing Seam Roofs

We install structural standing seam systems designed for low-slope and conventional commercial applications-attached to purlins or steel decks and engineered to handle roof loads without continuous sheathing in many cases. These are the workhorses for warehouses, distribution centers, industrial facilities, and big-box retail buildings with large low-slope areas. Structural panels can be designed and tested to meet specific wind uplift requirements in Nassau County’s coastal wind zones, which means your roof passes inspection and stays on during nor’easters. We coordinate panel widths, clip spacing, and fastener patterns with manufacturer-approved assemblies so engineering, submittals, and installation are aligned from day one.

Architectural Standing Seam for Visible Roofs

Architectural standing seam systems are installed over solid decks and used on schools, offices, religious buildings, and entry canopies where appearance matters as much as performance. We match panel profiles, widths, and colors to your building’s design intent while still addressing drainage slopes, underlayments, and wind-driven rain concerns specific to Nassau County’s open exposures. These systems integrate cleanly with wall panels, fascias, and parapet caps to create a finished look that reflects positively on your facility and brand.

Metal Retrofit Systems Over Existing Flat Roofs

When flat or low-slope roofs fail repeatedly due to ponding, membrane aging, or structural deflection, we install retrofit metal roofing systems that build a lightweight framing structure above the existing roof surface, creating new slopes to drains or gutters. This approach can solve chronic leaking without shutting down the building for a full tear-off, as long as structure and height allowances are verified during assessment. The existing roof is often left in place as a deck and secondary water barrier, limiting interior exposure during construction and reducing disruption to tenants and operations. We’ve completed retrofit projects on multi-tenant retail strips and light industrial buildings where full tear-off wasn’t operationally feasible.

Metal Roofs for Canopies, Entries, and Partial Areas

We also handle metal-clad canopies, vestibules, parapet caps, and accent roofs on retail centers, medical offices, and mixed-use properties. Even these smaller scopes demand commercial-grade detailing to integrate cleanly with main roof systems, wall flashings, and existing drainage paths. These projects often have tight timelines because they’re customer-facing, and we plan them to minimize impact on foot traffic and parking access.

Our Commercial Metal Roofing Installation Process

1. Site Assessment and Roof Survey

We start with a full roof survey: documenting existing systems, measuring slopes, inspecting deck condition, identifying ponding areas, and reviewing any existing drawings, leak histories, or prior roof reports. For existing buildings, we also consider tenant operations, access constraints, and rooftop equipment like RTUs, vents, and skylights that need coordination. This assessment determines whether you’re a candidate for direct replacement, retrofit, or a hybrid approach, and it identifies any structural, moisture, or code issues that will shape the scope and budget.

2. System Selection and Preliminary Design

Based on assessment findings, we present appropriate metal system options-structural standing seam, retrofit framing, or architectural panels-with pros, cons, and costs specific to your building and operational needs. This step includes confirming design wind and snow loads from the building’s location and exposure category, evaluating whether retrofit or direct replacement is feasible given existing structure and code limits on roof layers, and considering any phasing or tenant coordination requirements. We bring options, not sales pitches, so you can make an informed decision aligned with capital budgets and long-term facility planning.

3. Engineering, Permits, and Submittals

We coordinate any required engineering, including framing analysis, attachment schedules, and edge metal details to satisfy New York State Building Code and wind uplift requirements. Shop drawings, product data, color samples, and installation details are submitted for owner or architect review and for local building department approvals in Nassau County municipalities. This pre-construction phase ensures everyone-ownership, design team, and code officials-is aligned before any material orders or crew mobilization, reducing change orders and delays during the active phase.

4. Tear-Off / Overlay Preparation and Substrate Work

Some commercial metal roofing installation projects involve full tear-off to deck; others allow for overlays or retrofits over existing roofs. We determine the approach based on code, moisture surveys (core cuts or infrared scans), and structural capacity analysis. When tear-off is required, we phase it to maintain weather protection and minimize interior exposure. We repair or reinforce decking where needed, install any new framing for slope or retrofit systems, and prepare the substrate for insulation and underlayments. On a 40,000-square-foot warehouse in Westbury, we discovered localized deck rust during tear-off; we had steel repair crews on standby to address it within the schedule because surprises are part of commercial re-roofing, and planning for them keeps projects on track.

5. Insulation, Underlayments, and Moisture Management

We install code-compliant or upgraded insulation-often polyiso boards-to meet current energy code requirements, and we use tapered insulation systems where needed to improve drainage and eliminate ponding. Cover boards, vapor barriers, and underlayments are incorporated as required by the assembly design to manage condensation risk, achieve fire ratings, and control sound transmission. These layers aren’t optional; they’re essential for long-term performance, occupant comfort, and avoiding callbacks for leaks or condensation staining. On multi-tenant buildings, poor moisture management can lead to mold claims and tenant disputes, so we detail every transition and penetration carefully.

6. Metal Panel Installation and Detailing

Panels are laid out and installed following engineered attachment patterns, with special attention to perimeter and corner zones where wind loads are highest and edge failures typically occur. We integrate the metal roof with curbs for HVAC units, penetrations for vents and pipes, wall interfaces, and any existing roof sections using manufacturer-approved flashings and transition details. Quality-control checks on seams, fasteners, sealants, and panel alignment happen as installation progresses, not just at final inspection. We photograph key details and assemblies for as-built records and warranty documentation.

7. Edge Metal, Gutters, and Final Commissioning

We install edge metal, parapet caps, gutters, and downspouts designed for local wind and rain intensity, as well as any snow retention systems or rooftop safety features requested by ownership or required by code. Final inspections include water-shedding checks (controlled hose tests at critical areas), fastening verification, and as-built documentation for facility management. We provide warranty registration with the manufacturer, maintenance guidelines specific to the installed system, and contact information for future service or inspections. Handoff isn’t complete until ownership understands how to care for and verify the roof system going forward.

Designing for Nassau County Codes and Climate

Wind Uplift and Edge Detailing

Buildings in Nassau County must meet specific wind design requirements under the New York State Building Code, particularly in coastal and open exposure zones near the South Shore and bays. We use tested and rated metal roofing assemblies with documented clip spacing, fastener types, and edge metal configurations-typically UL 580 Class 90 or FM 1-90 assemblies-and these ratings and details are shown in our engineering submittals and shop drawings. Edge conditions are the most critical; improperly designed edge metal or insufficient fastening can lead to blow-off during high winds, even if the field of the roof is fine. We’ve seen edge failures on otherwise good roofs, so we over-detail and over-fasten perimeters as a standard practice.

Salt Air and Corrosion Resistance

Near the South Shore and bay-front areas, we recommend metal panel systems and fasteners suited for salt-laden air-often aluminum, galvalume with enhanced coatings, or painted steel with robust Kynar or similar paint systems that resist UV and corrosion. We also consider galvanic corrosion risks when interfacing metal roofing with existing metals, masonry walls, treated lumber nailers, and stainless hardware, using isolation washers, butyl tape, or non-conductive barriers where material sequences demand it. Ignoring galvanic issues leads to premature rust staining and fastener failure, especially in high-humidity coastal environments.

Drainage, Ponding, and Snow

Metal roofing design includes clear drainage paths to edge gutters, scuppers, or internal drains to avoid ponding that can stress panels and underlying insulation assemblies. We review existing drain locations and capacities during assessment and propose additional drains or slope adjustments where needed to meet current plumbing code flow rates. Snow and ice behavior on metal roofs is also considered-metal’s low friction allows snow to slide, which can damage gutters, landscaping, or pedestrian areas if not controlled. We design and install snow guards or retention systems where building use or site layout requires it, coordinating placement with structural loads and roof access paths.

Minimizing Disruption to Tenants and Operations

Phased Roofing and Temporary Protection

We break large roofs into phases, completing and temporarily waterproofing each section before moving on so that interior spaces remain protected throughout the project. For a three-tenant retail strip in Baldwin, we reroofed one tenant bay per week, maintaining full access and operations for the other two at all times. We schedule tear-off and noisy operations around business hours when possible, especially for retail, medical, and educational facilities where customer experience and patient care are priorities. Temporary tarps, roll goods, and staged material deliveries are planned in advance so weather delays don’t turn into interior leaks or tenant complaints.

Site Safety and Access Management

We set up controlled access zones, debris chutes, and signage to keep tenants, customers, and the public clear of overhead work and material handling areas. Crane time, panel deliveries, and dumpster placement are coordinated to preserve parking and access paths as much as feasible, and we communicate delivery schedules to property management so tenants can plan around any temporary restrictions. For multi-story or occupied buildings, we install perimeter netting, barricades, and overhead protection where required by OSHA and local safety codes, treating every project like someone’s workplace-because it is.

Communication and Progress Updates

We provide a single point of contact-typically the project manager-and regular updates on schedule, milestones, weather impacts, and any discoveries (wet insulation, structural issues, hidden penetrations) that may change scope or timing. For multi-tenant buildings, we assist ownership or management in preparing advance notices, door hangers, or signage to keep everyone informed about work hours, noise, and access changes. Clear communication reduces complaints, manages expectations, and helps preserve tenant relationships during construction.

Who We Serve: Commercial Buildings Across Nassau County

Building Types

TWI Roofing completes commercial metal roofing installation on a wide range of building types:

• Warehouses and distribution centers
• Light industrial and manufacturing facilities
• Retail strips, shopping centers, and big-box stores
• Office buildings, schools, and municipal structures
• Multi-family buildings and mixed-use properties (for appropriate roof sections)

Nassau County Coverage

Our crews regularly work throughout Nassau County, from inland commercial corridors to more exposed coastal and bayfront sites. Familiarity with local building departments, inspectors, and typical site conditions-like limited staging areas, shared parking, and older building stock-helps streamline permitting, coordination, and scheduling. We know where wind zones change, where salt air accelerates corrosion, and where municipal inspectors focus their attention, and we design and document projects accordingly.

Questions to Ask Any Commercial Metal Roofing Contractor

Technical and Experience Questions

• What commercial metal roofing systems are you certified or experienced to install, and on what building types?
• Can you provide recent commercial references for metal roofing projects of similar size, complexity, and occupancy?
• How do you address wind uplift, edge conditions, and code compliance for buildings in our exposure and occupancy category?
• What testing or approvals do your proposed assemblies carry (e.g., UL 580, FM 1-90, fire ratings)?
• Do you self-perform the work or subcontract metal panel installation?

Project Management and Warranty Questions

• How will work be phased to keep our operations running and our tenants or customers safe?
• What manufacturer and workmanship warranties will apply, and what are the conditions to keep them valid?
• How do you handle unforeseen conditions-structural issues, wet insulation, or hidden equipment-discovered during tear-off or preparation?
• What insurance coverage and safety programs do you maintain for commercial roofing work?

Frequently Asked Questions About Commercial Metal Roofing Installation

Can you install a metal roof over our existing flat or low-slope roof?
In many cases, yes-with a properly designed retrofit or overlay system. We evaluate structural capacity (can the building support the added dead load of framing, insulation, and panels?), existing moisture content (wet insulation must be removed or dried), and code limits on the number of roof layers. If conditions allow, retrofit systems avoid full tear-off, reduce interior exposure, and keep buildings operational during construction. If tear-off is required for code or performance reasons, we phase it to maintain weather protection.

How long will a commercial metal re-roof project take?
Duration depends on roof area, complexity, system type, and whether we’re doing full tear-off or retrofit. A 20,000-square-foot single-tenant warehouse with structural standing seam might take 3-4 weeks; a phased retrofit on a 50,000-square-foot multi-tenant retail center could take 6-8 weeks. We provide a phased schedule with milestone dates after the initial assessment, and we update it as weather, inspections, and any field conditions affect progress.

Will our building need to shut down during installation?
Most commercial metal roofing installation projects are completed with the building fully operational. We plan phasing, work hours, and access routes to minimize noise and disruption, coordinating any temporary closures or restricted access with ownership and tenants in advance. For roof sections over sensitive spaces (data centers, medical suites, food service), we schedule work during off-hours or provide additional temporary protection and dust control.

What maintenance does a commercial metal roof need?
Regular inspections (at least annually and after major storms), cleaning of drains and gutters to prevent overflow, prompt attention to any mechanical damage or loose fasteners, and checking sealants at penetrations and transitions. Metal roofs are low-maintenance compared to membranes, but neglect still shortens lifespan. We can provide maintenance plans or train facility staff on what to look for during routine building inspections.

Do you assist with budgeting and capital planning?
Yes. We provide budget estimates, lifecycle cost comparisons versus membrane or built-up roof systems, and phased approaches that spread capital spending over multiple budget years. For facility managers overseeing multiple buildings, we can assess your entire portfolio and prioritize roofs based on condition, remaining life, and risk of failure so you allocate resources strategically.

Plan Your Commercial Metal Roofing Project with a Nassau County Specialist

Commercial metal roofing installation is about more than ordering panels and hiring a crew-it’s about engineering systems that meet code, phasing work to protect operations, and delivering watertight performance for 30+ years in Nassau County’s wind, salt, and weather conditions. TWI Roofing brings experience across a range of metal systems and building types, from structural standing seam on warehouses to retrofit applications on aging flat roofs, and we focus on balancing durability, compliance, and operational needs throughout every project phase.

If you’re a building owner, facilities manager, or general contractor planning a commercial metal roofing project, schedule a site assessment with our team. We’ll review your existing roof, discuss metal system options suited to your building and budget, and develop a clear installation plan with engineering, phasing, and cost estimates you can use for RFPs or capital approval. Bring any previous roof reports, leak histories, tenant schedules, and operational constraints so we can tailor the solution to fit both your building and the business operating inside it.