If you need a staircase that handles real load, spans a wider tread, and holds up to daily use, a double stringer is the right structure.
NRK Welding fabricates custom double stringer staircases for residential and commercial clients throughout Southern Maine, handling everything from design and engineering through to installation.
What Is a Double Stringer Staircase?
A double stringer staircase (also called a dual stringer or side stringer staircase) uses two parallel steel beams, one running along each side of the flight, with treads spanning the full width between them. Both beams share the load, which distributes weight evenly and eliminates the flex you can get with narrower or centre-spine designs.
That structural rigidity is why double stringer stairs are the go-to choice for wide tread runs, high-traffic commercial spaces, and any project where load capacity can't be compromised. They can be built as open-riser or closed-riser, depending on your code requirements and aesthetic preference. Either way, the structural framework is the same.
At NRK Welding, every dual stringer staircase is fabricated to your exact dimensions and finished to suit your project: powder-coated, primed for paint, or brushed steel.
Double Stringer vs. Mono Stringer: Which Is Right for Your Project?
Both mono stringer staircases and double stringer staircases are steel. The difference comes down to how the load is carried, and what that means for your space.
| Feature | Double Stringer | Mono Stringer |
|---|---|---|
| Structure | Two parallel side beams | Single central spine |
| Visual profile | More enclosed; traditional or industrial look | Open and floating; minimal lateral framing |
| Load capacity | Higher: distributes weight across both beams | Lower: all load carried by the centre beam |
| Tread width | Well-suited to wider staircases | Better for narrower, feature staircases |
| Best application | Residential mains, commercial, mezzanines, high-traffic | Residential feature stairs, lofts, modern interiors |
| Cost | Moderate: more steel, straightforward fabrication | Can be lower or higher depending on span and finish |
For a main-floor staircase, basement connection, mezzanine, or any commercial application, a double stringer is almost always the stronger call. If your priority is a dramatic feature stair in a modern interior, a mono stringer may suit. We can walk you through the tradeoffs on a consultation call.
Contact us to talk through your options.
Open Riser Double Stringer Staircases
Want the structural confidence of a double stringer with a lighter, more open look? An open riser configuration removes the vertical panel between each tread, letting light through the staircase without affecting the rigidity that the dual beams provide.
Open riser double stringer stairs are a popular choice for loft conversions, industrial-style commercial spaces, and modern homes where the staircase needs to feel open without compromising under load. NRK Welding fabricates open riser double stringer stairs with the same precision and finish quality as our closed-riser work: tread material, finish, and railing style are all specified to your project.
Built for Residential and Commercial Projects
Residential
Homeowners across Southern Maine choose double stringer staircases for main-floor access, basement connections, and loft conversions. The structure handles the load demands of a family home without the engineering concerns that come with a mono stringer on a wide run. We work directly with homeowners, architects, and builders, coordinating dimensions and finish specs from the start so the staircase fits correctly the first time.
Commercial
For commercial offices, retail fitouts, and mezzanine access, double stringer stairs are the reliable structural choice. Two beams across a wider tread span mean that the staircase handles continuous foot traffic without compromise. We've fabricated double stringer steel staircases for commercial clients across York County and the Greater Portland area, working to site-specific dimensions and building code requirements throughout.
Tread & Railing Options
We fabricate double stringer stairs with tread and railing specifications to match your design and use case, agreed at the design stage and fitted during installation.
- Steel Plate Treads: Checker plate or smooth steel. Hardwearing and consistent with the stringer finish.
- Hardwood Treads: Solid timber fitted to the steel frame. Common in residential settings for warmth underfoot.
- Tempered Glass Treads: Structural glass for a high-specification, light-through finish.
Railing options include
custom steel handrails, cable railing systems, and glass panel systems, all fabricated and installed in-house, matched to the staircase finish.
What NRK Customers Say About Us
- Jhonatan VIana
This welder helped out my dad in a very difficult situation, thank you very much
- Lance T.
Amazing quality, and prompt service. Highly recommend and I will definitely use this shop in the future! Thanks nick.
- Jackson Mohr
Fantastic quality. Under the estimate provided and complete ahead of schedule. Cannot recommend Nick enough. Consummate professional and extremely skilled. Thanks again, Nick.
Frequently Asked Questions about Double Stringer Staircases
Get a Quote on Your Double Stringer Staircase
If you're ready to move forward or just want to talk through what's right for your project, we're easy to reach. NRK Welding serves residential and commercial clients throughout Southern Maine, from initial consultation through to installation day.
Call us for a free quote, and we'll get back to you promptly with next steps.
Serving Southern Maine: Saco · Portland · South Portland · Scarborough · Biddeford · Kennebunk · Old Orchard Beach · and throughout York County