SlimLine 38 Reynaers
SlimLine 38 Reynaers
Steel-look aluminium window system · Reynaers Aluminium (Belgium)
SlimLine 38 Reynaers is a slim steel-look aluminium window system by Belgian manufacturer Reynaers Aluminium. It was conceived for contemporary architecture where industrial aesthetics, precision detailing and strong energy performance must coexist. The system is the natural successor to the classic CS 38-SL, refined and upgraded with modern thermal insulation technology.
The minimal visible frame-and-sash width of just 67 mm — comparable to traditional steel window profiles — maximises the glazed area and floods interiors with natural light. Four distinct design variants (Classic, Cubic, Ferro and Functional) give architects and developers complete freedom to match the character of any building, from heritage renovations to bold new-build projects.
SlimLine 38 is available in a standard energy version and a High Insulation (HI) upgrade. The HI version achieves a frame Uf of 1.9 W/m²K and a whole-window Uw of 0.99 W/m²K, making it suitable for passive house applications. Optional fire resistance (EW 30) and burglar resistance (RC2) extend its use to the most demanding commercial and public-sector projects.
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| Uf coefficient (frame, HI version) | 1.9 W/m²K |
| Uw coefficient (window, HI version) | 0.99 W/m²K * |
| Air permeability | Class 4 (600 Pa) |
| Water tightness | Class 9A (600 Pa) |
| Wind load resistance | Class C4 (1600 Pa) |
| Sound insulation Rw | up to 45 (-1;-5) dB |
| Durability | Class 3 (20,000 cycles) |
| Frame installation depth | 99 mm |
| Sash installation depth | 76 mm |
| Min. frame width (inward opening) | 38.5 mm |
| Min. sash width (inward opening) | 23 mm |
| Min. frame+sash (inward opening) | 67 mm |
| Max. sash height | 2800 mm |
| Glazing rebate height | 13.5 mm |
| Burglar resistance | RC2 |
| Fire resistance (optional) | EW 30 |
| Max. sash weight | 170 kg |
| Profile material | Aluminium |
| Manufacturer | Reynaers Aluminium |
| Country of manufacture | Belgium |
| Dry glazing | ✔ |
| Silicone glazing | ✔ |
| Internal glazing | ✔ |
| Bead glazing | ✔ |
| Double / triple glazing | ✔ |
The 67 mm frame-and-sash sight line reproduces the proportions of classic steel profiles while delivering the durability and insulation of modern aluminium.
Classic, Cubic, Ferro and Functional — each with a distinct surface treatment and shadow-gap profile to suit industrial, contemporary or traditional buildings.
Uf 1.9 W/m²K and Uw 0.99 W/m²K in the HI version — passive-house-ready performance with no compromise on the slim silhouette.
Rw up to 45 dB — effective acoustic comfort in urban environments, offices and residential developments near busy roads or railways.
Hidden hinges and no plastic cover caps deliver the clean, uninterrupted lines that define the steel-look aesthetic from every angle.
The aluminium profile resists corrosion, UV degradation and deformation for 40–50 years and more without repainting or structural maintenance.
RC2 burglar resistance as standard; optional EW 30 fire resistance makes the system suitable for safe-evacuation routes and sensitive buildings.
Full RAL palette, anodising, matt and textured coatings, dual-colour inside/outside finish — all colour-stable for the lifetime of the window.
SlimLine 38 replicates the narrow sightlines of historic steel windows, making it the preferred choice when upgrading listed or industrial buildings without altering facade proportions.
The HI version combined with triple glazing and a thermal-break installation meets the strict energy requirements of passive and nearly zero-energy buildings.
- Classic — inclined surface
- Cubic — stepped surface
- Ferro — shadow gaps
- Functional — flush finish
- Fixed windows
- Casement windows
- Tilt-and-turn windows
- Outward-opening windows
- Balcony doors
- Corner glazing
- Fire-resistant version (EW 30)
- Burglar-resistant version (RC2)
- RAL painting (any colour)
- Anodising
- Matt coatings
- Textured coatings
- Dual-colour finish (inside / outside)
- Custom-order coatings
Logi24 offers professional consultation, supply and installation of SlimLine 38 Reynaers aluminium windows across Europe. Our specialists will help you select the right design variant, insulation level, colour, glazing type and hardware for your project — whether it is a heritage renovation, a new private home or a large commercial development. A warranty is provided on both the products and the installation work. Please contact our team for detailed information and a project-specific cost estimate.
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What is SlimLine 38 Reynaers?SlimLine 38 Reynaers is a slim steel-look aluminium window system by Belgian manufacturer Reynaers Aluminium. It is the successor to the CS 38-SL and is designed for contemporary and renovation projects where industrial aesthetics, energy efficiency and long-term durability are equally important. The name refers to the ultra-narrow 38 mm minimum frame width that replicates the sightlines of traditional steel profiles.
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What design variants does SlimLine 38 offer?The system is available in four design variants: Classic (inclined surface with a sober industrial look), Cubic (stepped surface for a robust, three-dimensional appearance), Ferro (straight lines and shadow gaps for a refined, contemporary feel) and Functional (flush, clean finish that suits any building style). All variants share the same structural and insulation performance.
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What are the thermal insulation values of SlimLine 38?In the High Insulation (HI) version, the frame Uf coefficient is 1.9 W/m²K. Combined with a high-performance glazing unit of Ug 0.6 W/m²K and a warm-edge spacer, the whole-window Uw coefficient reaches 0.99 W/m²K (at standard size 1.23×1.48 m, 36 mm glass). The standard version achieves Uf 2.5 W/m²K and Uw 1.2 W/m²K.
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Is SlimLine 38 suitable for passive houses?Yes. The HI version combined with triple glazing and a correctly executed thermal-break installation meets the energy requirements of passive and nearly zero-energy buildings. Consultation with a specialist is recommended to verify compliance with the specific passive standard applicable to your project.
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What are the maximum sash dimensions?The maximum sash height is 2800 mm and the maximum sash weight is 170 kg. Exact permissible dimensions depend on the chosen design variant, hardware and glazing unit. Logi24 will calculate the specifications for your specific project and configuration.
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What glazing units can be used with SlimLine 38?The system supports dry glazing, silicone glazing, internal glazing and bead glazing. Both double and triple glazing can be accommodated without altering the ultra-slim external appearance of the profile. The glazing rebate height is 13.5 mm.
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How durable is the SlimLine 38 system?The system has been tested to 20,000 opening/closing cycles (Class 3 per EN 12400). The aluminium profile is resistant to corrosion, UV radiation and structural deformation. With proper maintenance, the service life of SlimLine 38 constructions is 40–50 years and more.
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What colours and finishes are available?The full RAL colour palette is available, alongside anodising, matt and textured powder coatings, and a dual-colour finish with different colours inside and outside. All coatings are UV-stable and retain their appearance for the lifetime of the window without repainting.
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Is SlimLine 38 suitable for commercial and heritage projects?Yes. SlimLine 38 is widely used in offices, hotels, residential developments and public buildings. Its steel-look proportions make it particularly suitable for renovating historic or listed buildings with original steel frames. The optional fire resistance rating (EW 30) qualifies it for escape routes and fire-compartment facades.
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What is the service life of SlimLine 38 Reynaers?With routine cleaning and periodic hardware maintenance, Reynaers aluminium constructions reliably serve 40–50 years and more. Unlike steel, aluminium does not rust; unlike uPVC, it does not warp, yellow or lose structural integrity under temperature extremes or UV exposure.
SlimLine 38 Reynaers is a slim steel-look aluminium window system developed by Belgian manufacturer Reynaers Aluminium for projects where minimalist industrial aesthetics and high energy performance must go hand in hand. As the successor to the proven CS 38-SL profile, it has been upgraded with modern thermal insulation technology while retaining the ultra-narrow sightlines that define the steel-window aesthetic. The minimum combined frame-and-sash visible width of 67 mm makes it virtually indistinguishable in proportion from traditional steel profiles — but with far superior insulation and a service life measured in decades.
Four design variants — Classic, Cubic, Ferro and Functional — allow the system to adapt to very different architectural languages. The Classic variant features a gently inclined surface that echoes the original industrial profile character. Cubic adds a stepped, three-dimensional robustness. Ferro introduces clean straight lines and precisely defined shadow gaps. Functional offers a contemporary flush finish that integrates seamlessly into any facade composition. All four variants are available in both a standard energy version and the High Insulation (HI) upgrade.
The High Insulation version achieves a frame Uf coefficient of 1.9 W/m²K. Paired with a triple-glazed unit of Ug 0.6 W/m²K and a warm-edge spacer, the whole-window Uw value reaches 0.99 W/m²K — making SlimLine 38 HI fully compatible with passive house construction. Air permeability reaches Class 4 (600 Pa), water tightness Class 9A (600 Pa) and wind load resistance Class C4 (1600 Pa), ensuring outstanding weatherproofing across all climatic conditions.
Sound insulation is another key strength: the system delivers Rw up to 45 (-1;-5) dB depending on glazing choice. This level of acoustic performance is highly effective in urban environments, near busy roads or rail corridors, and in mixed-use commercial developments where noise control is a planning requirement.
Security is addressed at every level of the specification. Burglar resistance class RC2 is available as standard, protecting against opportunistic and even determined forced-entry attempts. For buildings requiring additional life-safety measures, an optional fire-resistance rating of EW 30 can be specified, qualifying the system for use in fire-compartment facades and safe-evacuation routes — a capability rarely available in slim-profile systems of this type.
Concealed hinges and the complete elimination of plastic cover caps are not just aesthetic choices: they are expressions of the engineering philosophy behind SlimLine 38. Every visible surface is a clean, high-quality aluminium finish, contributing to the precise and durable character of the system. The aluminium profile is UV-stable and retains its colour and geometry throughout its entire service life without repainting, resealing or structural intervention.
SlimLine 38 Reynaers is the outstanding choice for renovation of buildings with historic steel-framed windows, where planning constraints require the new windows to replicate the narrow sightlines and industrial character of the originals while meeting contemporary energy and security standards. It is equally suited to new-build projects — modern private homes, loft-style apartments, boutique hotels, offices and cultural institutions — wherever a refined, pared-back aesthetic is the design intent.
Logi24 supplies and installs SlimLine 38 Reynaers across Europe. Our team provides full project support from initial specification and design-variant selection through to delivery, installation and warranty coverage. Contact us for a detailed consultation and project-specific quotation.