Discover the Ottostumm FerroFinestra W75 TB steel window system at Portamet. Ultra-slim steel window frames with polyamide thermal breaks, premium finishes (steel, stainless, Cor-Ten, bronze), CE-certified performance, and global delivery. Ideal for architects, homeowners, and developers. 

• cold formed and sharp-edged 1.5 mm thick steel profiles 

• continuously laser welded profile, high mechanical performance 

• can be both internally and externally flush or overlapping, or externally flush and internally overlapping 

• profile depth compatible with insulating glass up to 56 mm 

• glass-fibre reinforced polyamide insulator 

• wide choice of glazing beads, rectangular, triangular and double “L” shape 

• EPDM co-extruded sealing gaskets wide choice of specific fittings, including both visible and conceived hinges 

• side-hung, top-hung and bottom-hung windows, tilt and turn, pivoting windows, sliding and folding doors 

• surface finishes in any customized or RAL colours, for a great planning freedom

Historic Restorations: The W75 TB is ideal for preserving original aesthetics in heritage buildings. Its slim frames and authentic muntin designs allow seamless integration into conservation areas and listed properties. 

Contemporary Architecture: For modern builds, this steel system enables large-format glazing with structural integrity. It supports clean lines and expansive views, making it a favorite among architects designing high-end homes, offices, and hospitality spaces.

Transform your architectural vision with the W75 TB system. Whether you're designing a luxury villa, restoring a historic landmark, or building a modern masterpiece, Portamet is your trusted steel windows manufacturer. Contact us today to receive a consultation or request a quote.

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Ottostumm FerroFinestra W75 TB is a steel window and door profile system that marries ultra-slim historic steel aesthetics with cutting-edge thermal performance. This advanced FerroFinestra W75 TB series offers the look of classic industrial-style windows – thin sightlines and elegant profiles – combined with modern benefits like energy efficiency, security, and design flexibility. It’s the ideal solution for both heritage building restorations and sleek contemporary architecture, preserving authentic style while meeting today’s highest standards. Portamet fabricates each Ottostumm steel window to your specifications, whether you need to replicate vintage metal windows or create expansive modern glass façades. 

Features & Benefits 

W75 Thermal Break Performance 

Engineered with an effective polyamide thermal break, the W75 TB system delivers excellent insulation for a steel window. The fiberglass-reinforced core separates the interior and exterior steel sections, dramatically reducing heat transfer. This means interiors stay warm in winter and cool in summer, and the windows meet strict modern energy codes. You get the beauty of steel windows with a thermal barrier that achieves high performance ratings in U-value and condensation resistance – a perfect blend of form and function. 

Ultra-Slim Steel Aesthetics 

FerroFinestra W75 TB maintains the ultra-slim sightlines that steel windows are famed for. Visible frame profiles can be as narrow as a few centimeters, maximizing glass area and natural light. These slender, sharp-edged profiles recreate the look of early 20th-century steel windows, making them ideal for historical renovations or for achieving that sought-after industrial chic style in new builds. Despite the slim dimensions, the high-strength steel allows larger panes and minimal frames, creating an elegant, airy aesthetic impossible with bulkier aluminum or wood systems. 

Historic Restoration Suitability 

Originally inspired by late 19th-century hot-rolled steel windows, the W75 TB system is tailor-made for heritage restoration. Its profiles and muntin options echo classic steel window designs, satisfying preservationists and architects working on landmark buildings. We offer specialized hardware and accessories that can mimic vintage window handles, hinges, and latch styles, ensuring authentic details. With W75 TB, historic buildings can upgrade to double or triple glazing and thermal performance without altering their historic character – truly the best of old and new. 

Security & Strength 

Built from high-grade steel up to 1.5–2 mm thick, Ottostumm W75 TB windows provide exceptional strength and security. Steel is several times more rigid and robust than aluminum, so these slim frames still resist deformation and forced entry. Multi-point locking systems and optional security glass can be integrated for enhanced burglary protection. The inherent durability of steel means Ottostumm steel windows will last for decades with minimal maintenance, even in heavy-use commercial settings. You gain peace of mind that your elegant windows are also a solid barrier against intruders and the elements. 

Design Versatility & Customization 

The FerroFinestra W75 TB is incredibly versatile, accommodating virtually any design vision. It supports all common opening types – inward or outward-opening casements, tilt-and-turn windows, top-hung awnings, pivoting windows, even sliding and bi-folding door configurations. Profiles can be configured as internally or externally flush or overlapping, adapting to modern minimalist or traditional putty-glazed looks. We craft each unit to order, in bespoke sizes and shapes – from classic divided-light casements to sweeping arched windows or floor-to-ceiling glass walls. A wide range of hardware styles (both contemporary and replicas of antique originals) are available to suit your project. In short, slim thermally broken steel profiles like W75 TB offer tremendous flexibility for custom designs. 

Materials & Finishes 

One of the hallmarks of the W75 TB system is the array of materials and finishes available, allowing you to achieve exactly the look and durability you desire: 

• Steel (Painted or Galvanized): The standard option is precision-formed steel which can be galvanically zinc-coated for corrosion resistance. We then finish your windows in any RAL color powder coat or a custom paint, including matte, gloss, or textured effects. Classic black or architects’ grey are popular for that timeless industrial look, but you can choose any color palette to match your design. 

• Stainless Steel: For ultimate longevity and a sleek modern appearance, W75 TB profiles can be fabricated in stainless steel (grade 1.4404). Stainless steel frames are perfect for harsh climates or seaside projects, as they resist rust and weathering while offering a distinctive brushed or polished metal finish. 

• Cor-Ten Weathering Steel: If you desire a natural patina, Cor-Ten steel is an option. This alloy develops a stable rust-like oxidized surface that protects the inner steel – ideal for an organic, weathered aesthetic that blends with historic brick or modern concrete facades. The earthy color and texture of Cor-Ten make a bold architectural statement. 

• Architectural Bronze: For the most luxurious heritage look, we offer an architectural bronze variant of this system (marketed as BronzoFinestra B75 TB). Bronze is a timeless, noble metal that ages gracefully, developing a rich patina over time. Bronze frames impart unmatched elegance and are often used in prestigious projects or historic restorations where authenticity and beauty are paramount. 

All materials come with bespoke finishing options – from hand-brushed or burnished surfaces to clear lacquer that highlights the metal’s natural character. Whether you prefer the modern uniformity of powder-coated steel or the living finish of bronze, Portamet will deliver extraordinary craftsmanship. Every window is finished to both protect the material and to complement your interior and exterior design. 

Applications: Heritage & Modern 

Heritage Restoration Projects FerroFinestra W75 TB is a top choice for restoring heritage and period properties. Many historic buildings from the 19th and 20th centuries featured thin steel windows – and W75 TB allows you to maintain that original look while upgrading performance. The profiles can match historic sightlines and even accommodate true divided lites or decorative glazing bars to replicate old steel casements. With thermal insulation and double/triple glazing, you can bring museums, converted lofts, or listed properties up to today’s comfort and efficiency standards without compromising their architectural integrity. These windows have been used in the renovation of factories-turned-lofts, Victorian and Art Deco buildings, and even castles, where preserving the authentic window appearance is crucial. Conservation officers appreciate that W75 TB retains the historic steel window character down to the details, from slim mullions to traditional hardware, all while being a brand-new high-performance product. 

Contemporary Architecture & Modern Designs 

Modern architects and luxury home builders love W75 TB for its sleek minimalism and strength. In new construction, these Ottostumm steel windows enable expansive glass openings and clean lines that elevate modern design aesthetics. The inherent strength of steel allows for large floor-to-ceiling windows or multi-panel door systems that flood spaces with light, all within ultra-thin frames that aluminum systems cannot match. The W75 TB system seamlessly fits chic urban apartments, modern farmhouses, high-end retail storefronts, and cutting-edge commercial buildings. The ability to choose custom finishes (like bold colors or stainless steel) also lets architects make a style statement. Whether it’s a minimalist luxury villa with huge glass walls or a trendy restaurant with industrial-style steel partitions, FerroFinestra W75 TB provides the perfect blend of modern style, slim profiles, and reliable performance. Its versatility means it complements both concrete-and-glass contemporary facades and warm wooden interiors, bridging design eras with ease. 

Technical Specifications 

For those interested in the technical details, here are some key specifications of the Ottostumm FerroFinestra W75 TB system: 

• Profile Depth: 75 mm frame depth, allowing the use of high-performance insulating glass units up to ~52 mm thick (suitable for double or triple glazing). This deep profile and large glazing pocket ensure excellent thermal and acoustic insulation capabilities. 

• Thermal Break Construction: Fiberglass-reinforced polyamide strips create a robust thermal break between inner and outer frame sections. This advanced thermal barrier dramatically reduces heat conduction through the steel and contributes to low overall U-values (meeting or exceeding demanding energy regulations). 

• Profile Design & Fabrication: Cold-formed steel profiles with sharp edges, 1.5 mm wall thickness, continuously laser-welded for high precision and strength. Despite the slim appearance, the construction is extremely rigid and durable. All profiles are welder-friendly for fabrication of custom shapes. Glazing Bead Options: Wide selection of glazing bead shapes to tailor the interior look – from slim rectangular beads for a minimalist appearance to angular or double-“L” shaped beads that mimic historic putty glazing. These beads securely hold the glass and can be chosen to suit aesthetic preferences. 

• Seal & Gaskets: Dual EPDM weather seals ensure top performance in air and water tightness. The system is tested and certified for air infiltration, water penetration, and wind load resistance according to international standards, making it suitable for exposed external applications. Co-extruded glazing gaskets provide a continuous seal for long-lasting weatherproofing. 

• Hardware and Operations: Supports both modern and classic-style hardware. Hinges can be visible (surface-mounted for traditional look) or concealed for a cleaner appearance. Multi-point locking mechanisms, tilt-turn handles, and all standard operations are supported. Opening types include side-hung (casement) windows and doors, bottom-hung (hopper) windows, top-hung windows, tilt-and-turn windows, pivot windows, as well as sliding and folding (bi-fold) door systems – covering virtually any requirement. 

• Configurations: Available in single or double sash configurations, with the possibility of combining fixed and operable elements in one frame. Frames can be designed with either flush or overlapping sash/frame profiles on either side, giving architects flexibility in aesthetic (e.g., both interior and exterior flush for a flat look, or exterior overlap to resemble old steel windows with putty-glazed panes). 

• Surface Finishes: As noted, the profiles can be finished in any RAL color powder coat, specialized varnishes, or authentic metal patinas. This includes smooth paint, textured, metallic, or anodized-like coatings. The finish options allow the windows to harmonize with any interior decor or exterior facade treatment. 

• Standards Compliance: FerroFinestra W75 TB is the most advanced thermally insulated steel system in Ottostumm’s lineup, and it meets rigorous European and international standards. The steel used is largely recycled content, contributing to LEED and Green Building credits, and the system’s high insulation can help with energy efficiency certifications (like Passive House or Net-Zero energy targets when combined with appropriate glass). In summary, it offers state-of-the-art performance without sacrificing the heritage look. (For detailed technical datasheets or performance certificates, please contact Portamet – we can provide U-value calculations, structural test results, and other technical documentation upon request.)

 Portamet – Expert Steel Window Fabricator 

Portamet is a trusted expert in crafting bespoke steel windows and doors, proudly bringing the Ottostumm | Mogs range to discerning clients. With over a decade of experience in high-end steel and glass fabrication, our company is equipped to realize the full potential of the FerroFinestra W75 TB system for your project. Here’s why architects, builders, and homeowners choose Portamet as their steel window partner: 

• Authorized Manufacturer: Portamet is an authorized fabricator of Ottostumm steel windows. Our team is trained in the proper assembly and finishing of the W75 TB profiles, ensuring your windows are built to Ottostumm’s exacting Swiss quality standards. We marry Italian design flair with Polish craftsmanship and precision. 

• Custom Solutions: Every project is unique – we work closely with clients to adapt the W75 TB system to their specific needs. Whether it’s a one-of-a-kind arched window, an entire façade of matching steel doors and windows, or replicating an original window from a historical photo, we have the expertise to deliver. Our engineers can assist with design details, and our modern production facility can handle custom dimensions or unusual configurations with ease. 

• Quality & Finish: Fabricating steel windows is an art as much as a science. At our Gdańsk, Poland factory, we use state-of-the-art machinery for cutting, welding, and finishing, while maintaining artisan attention to detail. Each window or door is meticulously finished – from smooth welds that are virtually invisible, to a durable coating or patina. We conduct thorough quality checks for operability, finish, and fit before shipping. The result is a product that not only looks stunning but also performs flawlessly for decades. 

• Global Delivery & Installation Support: Portamet ships steel windows and doors across Europe, the USA, Canada and beyond. Our logistical experience ensures your products arrive safely and on schedule. We can supply frames ready for installation, and if needed, connect you with our network of installers or provide guidance for your builders on site. Even after delivery, our customer service continues – we stand behind our products with warranties and are always available for any support or maintenance needs. 

• Competitive Lead Times: Despite being custom-made, our efficient processes allow reasonable manufacturing lead times. We understand construction schedules are critical; thus, we strive to deliver your steel windows on time and coordinate with your project timeline.

• Consultation & Expertise: Not sure if W75 TB is right for you, or need advice on glass specs, opening styles, or finish selection? Our knowledgeable team is here to help from the earliest stages. We provide professional consultation to ensure you get the optimal solution – perhaps even mixing systems (we also offer Secco, Jansen, Forster profiles) if a project demands it. Our goal is to realize your vision in the most effective way. 

When you partner with Portamet, you get more than just a supplier – you get a dedicated ally in creating show-stopping steel windows and doors that will elevate your space. 

Ready to Elevate Your Project? – Contact Us 

Don’t miss the opportunity to infuse your project with the unmatched style and performance of Ottostumm FerroFinestra W75 TB steel windows and doors. Contact Portamet today to discuss your needs, get expert guidance, or request a quote. Our team is eager to assist you in designing the perfect steel fenestration solution – from initial consultation through installation support. Transform your property with these slim, thermally broken steel profiles that blend historic charm with modern efficiency. Reach out now and let’s begin crafting your bespoke steel windows: we’re ready to help make your vision a reality with FerroFinestra W75 TB!