15kW Roofmaster Generator

The 15kW Roofmaster Generator—known as Ol' Sparky—is purpose-built for roofing contractors and demanding construction jobsites. Unlike typical portable generators, it delivers 15,000 continuous watts of clean power with less than 5% total harmonic distortion, all-copper windings, and the output needed to operate professional roofing equipment including Leister automatic hot-air welders.

Ol' Sparky was designed around the realities of commercial roofing. Its heavy-duty frame rides on a Roofmaster NFL wheel kit, while the integrated lifting eye makes it easier to move the generator from ground level to the roof. Locking casters, an hour meter, an 11-gallon fuel tank, and service-friendly engine mounting make it practical for daily contractor use.

This Roofmaster generator is powered by a 20 HP Honda engine and is designed for easy service access. The removable engine bracket, slotted service mount for oil drainage, and accessible spark plugs help simplify routine maintenance. The generator is fully insulated, and when using the installed receptacles the frame serves as the ground. Battery sold separately (item 900001).

Why Roofers Choose the 15kW Roofmaster Generator

• 15,000 continuous watts of output
• Clean power with less than 5% total harmonic distortion
• All-copper generator windings
• Heavy-duty frame designed for roofing and construction environments
• Roofmaster NFL wheel kit for jobsite mobility
• Heavy-duty lifting eye for ground-to-roof handling
• 11-gallon fuel tank
• Hour meter
• Locking caster system
• Service-accessible engine mounting
• Designed to support professional Leister hot-air welding equipment

Built for Real Roofing Jobsites

A roofing jobsite places very different demands on a generator than occasional residential or recreational use. Equipment may run for extended periods, power must remain stable, and the generator often needs to be moved across rough surfaces or lifted onto a roof. The 15kW Roofmaster Generator was developed around those conditions rather than adapted from a general-purpose portable generator.

Its 15,000-watt continuous output is especially important for contractors using high-demand equipment. Many portable generators are marketed around peak or surge wattage, but continuous output is the more meaningful number when powering equipment for long periods. Ol' Sparky is designed to deliver sustained power for roofing and construction applications where reliable output matters throughout the workday.

Clean power is another key consideration. With less than 5% total harmonic distortion, the Roofmaster generator provides stable electrical output for professional equipment, including electronic controls and hot-air welding equipment.

OEM-Approved Engine Application

Roofmaster is an approved OEM for the engine used on this generator. Our engine-powered equipment is tested and benchmarked with the engine manufacturer as part of the OEM approval process before production approval.

This process helps verify that the engine is properly matched to the generator's operating requirements and intended commercial use, giving contractors confidence that the powerplant and equipment have been evaluated as a complete application rather than simply assembled from unrelated components.

Designed with the Roofer in Mind

When Roofmaster designed Ol' Sparky, serviceability was a major priority. Roofing equipment does not always receive perfect preventative maintenance, so the generator was engineered to make routine service as simple and accessible as possible.

The engine oil drain is positioned to drain directly through the frame, helping make oil changes cleaner and reducing the chance of oil collecting on the generator frame. The spark plugs can be serviced within the frame, and the air filter is readily accessible for inspection and replacement.

Roofmaster also designed access around components that commonly require much more work on other generators. If the recoil starter needs service, a removable panel can simply be unbolted for access. On some conventional generator frames, comparable service can require cutting or torching part of the frame just to reach the component.

The electrical panel was designed with the same philosophy. Removing three screws allows the panel to fold down, providing direct access for electrical service, inspection, or panel replacement without dismantling the generator.

These details may seem small, but they can make a major difference in the field. The goal was to build a 15kW generator that roofing contractors could actually maintain and repair without turning routine service into a major project.

Power & Receptacles

• 15,000 continuous watts
• Four 120V / 20A GFCI receptacles
• One 240V / 30A L6-30 receptacle
• One 250V / 50A CS receptacle
• Circuit-breaker protection
• Ground lug
• Less than 5% total harmonic distortion
• All-copper windings

Built for Roofing Equipment

With 15,000 continuous watts available, the Roofmaster generator is designed to supply the power required by professional single-ply roofing equipment, including Leister VARIMAT automatic welders. Depending on the connected equipment and jobsite load, contractors may use the generator to power one or multiple roofing tools.

Watch Ol' Sparky run two V2s using a CS Drop Cord and Spider Box:

Service and Maintenance

Service and maintenance for the Honda GX630:

This generator is intended for construction applications including roofing contractor jobsite operations.