SlimLine 38 Reynaers
SlimLine 38 Reynaers
Steel-look aluminium window system · Reynaers Aluminium (Belgium)
SlimLine 38 Reynaers is a slim-profile, steel-look aluminium window system from the Belgian manufacturer Reynaers Aluminium. It is created for contemporary architecture where industrial aesthetics, precision detailing and high energy efficiency need to come together. The system is a natural continuation of the classic CS 38-SL profile, upgraded with modern thermal insulation technology.
A minimum visible frame and sash width of just 67 mm — comparable to traditional steel profiles — maximises the glazed area and fills interiors with natural light. Four distinct design variants (Classic, Cubic, Ferro and Functional) give architects and developers complete freedom to match the character of the profile to any building, from the restoration of historic properties to bold new-build projects.
SlimLine 38 is available in a standard energy-efficient version and in a high-insulation (HI) version. The HI version delivers a frame coefficient Uf of 1.9 W/m²K and an overall window coefficient Uw of 0.99 W/m²K, making it suitable for use in passive houses. Optional fire resistance (EW 30) and burglar resistance (RC2) extend the system's scope to the most demanding commercial and public buildings.
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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 | 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 | ✔ |
A visible frame and sash line of just 67 mm reproduces the proportions of classic steel profiles while delivering the durability and thermal performance of modern aluminium.
Classic, Cubic, Ferro and Functional — each with its own surface treatment and shadow-gap profile, suited to industrial, contemporary or traditional buildings.
Uf 1.9 W/m²K and Uw 0.99 W/m²K in the HI version — passive house-ready performance without compromising the slim silhouette.
Rw up to 45 dB — effective acoustic comfort in urban settings, offices and residential complexes near busy roads or railways.
Concealed hinges and the absence of plastic caps ensure clean, continuous lines that define the steel-look aesthetic from every angle.
The aluminium profile resists corrosion, UV degradation and deformation for 40–50 years or more without repainting or structural maintenance.
RC2 burglar resistance as standard; optional EW 30 fire resistance makes the system suitable for escape routes and buildings with elevated safety requirements.
The full RAL palette, anodising, matte and textured finishes, two-tone interior/exterior finishes — all options retain their colour throughout the window's service life.
SlimLine 38 replicates the narrow lines of historic steel windows, making it the preferred choice when modernising heritage buildings or industrial properties without altering the facade's proportions.
The HI version combined with high-performance triple glazing and thermally broken installation meets the strict energy requirements of passive and nearly zero-energy buildings.
- Classic — chamfered surface
- Cubic — stepped surface
- Ferro — shadow gaps
- Functional — flush finish
- Fixed windows
- Side-hung 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
- Matte finishes
- Textured finishes
- Two-tone finish (interior / exterior)
- Custom finishes on request
Logi24 offers professional consultation, supply and installation of SlimLine 38 Reynaers aluminium windows across Europe. Our specialists will help you choose the right design variant, insulation level, colour, glazing type and hardware for your project — whether it's a historic building restoration, a new private home, or a major commercial development. A warranty is provided on both the products and the installation work. Contact our team for detailed information and a cost estimate for your project.
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What is SlimLine 38 Reynaers?SlimLine 38 Reynaers is a slim-profile, steel-look aluminium window system from the Belgian manufacturer Reynaers Aluminium. It is a successor to the CS 38-SL profile and is intended for contemporary projects and restoration work where industrial aesthetics, energy efficiency and durability are equally important. The name refers to the ultra-slim minimum frame width of 38 mm, echoing the lines of traditional steel profiles.
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What design variants does SlimLine 38 offer?The system is available in four design variants: Classic (chamfered surface with an understated industrial look), Cubic (stepped surface for an expressive, three-dimensional appearance), Ferro (straight lines and precisely defined shadow gaps for a refined contemporary look) and Functional (flush finish, suited to any building style). All four variants share the same structural and thermal insulation performance.
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What are the thermal insulation figures for SlimLine 38?In the high-insulation (HI) version, the frame coefficient Uf is 1.9 W/m²K. Combined with a high-performance glazing unit of Ug 0.6 W/m²K and a warm-edge spacer, the overall window coefficient Uw reaches 0.99 W/m²K (for the standard size of 1.23×1.48 m, 36 mm glass). The standard version delivers 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 correctly executed thermally broken installation meets the energy requirements of passive and nearly zero-energy buildings. We recommend consulting a specialist to confirm compliance with the specific passive house standard applicable to your project.
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What are the maximum sash dimensions?Maximum sash height is 2800 mm, and 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 particular project and configuration.
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What glazing 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 installed without changing 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 for 20,000 opening/closing cycles (Class 3 per EN 12400). The aluminium profile resists corrosion, UV radiation and structural deformation. With proper maintenance, SlimLine 38 structures have a service life of 40–50 years or more.
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What colours and finishes are available?The full RAL colour palette is available, along with anodising, matte and textured powder coatings, and two-tone finishes with different colours inside and outside. All finishes are UV-resistant and retain their appearance throughout the window's service life without repainting.
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Is SlimLine 38 suitable for commercial and historic projects?Yes. SlimLine 38 is widely used in offices, hotels, residential complexes and public buildings. Its steel-look proportions make it especially suited to restoring historic or heritage-protected buildings with original steel frames. The optional fire-resistance class (EW 30) allows the system to be used on escape routes and fire-rated facades.
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What is the service life of SlimLine 38 Reynaers?With regular cleaning and periodic hardware maintenance, Reynaers aluminium structures reliably last 40–50 years or more. Unlike steel, aluminium does not rust; unlike PVC, it does not warp, yellow, or lose structural integrity under extreme temperatures or UV exposure.
SlimLine 38 Reynaers is a slim-profile, steel-look aluminium window system developed by the Belgian manufacturer Reynaers Aluminium for projects where minimalist industrial aesthetics and high energy efficiency need to go hand in hand. As the successor to the well-established CS 38-SL profile, it has been upgraded with modern thermal insulation technology while retaining the ultra-slim lines that define the steel window aesthetic. A minimum overall visible frame and sash width of 67 mm makes it virtually indistinguishable in proportion from traditional steel profiles — but with far superior thermal performance and a service life measured in decades.
Four design variants — Classic, Cubic, Ferro and Functional — allow the system to adapt to a wide range of architectural languages. The Classic variant features a slightly chamfered surface that echoes the character of the original industrial profile. Cubic adds a stepped, three-dimensional expressiveness. Ferro introduces clean straight lines and precisely defined shadow gaps. Functional offers a contemporary flush finish that blends seamlessly into any facade composition. All four variants are available in both the standard energy-efficient version and the high-insulation (HI) version.
The high-insulation version delivers a frame coefficient Uf of 1.9 W/m²K. Combined with a triple-glazed unit of Ug 0.6 W/m²K and a warm-edge spacer, the overall window coefficient Uw reaches 0.99 W/m²K — making SlimLine 38 HI fully compatible with passive house construction. Air permeability reaches Class 4 (600 Pa), water tightness reaches Class 9A (600 Pa), and wind load resistance reaches Class C4 (1600 Pa), providing excellent weather protection in all climate conditions.
Sound insulation is another key strength of the system: it delivers Rw up to 45 (-1;-5) dB depending on the glazing selection. 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. RC2 burglar resistance is available as standard, protecting against opportunistic and even targeted break-in attempts. For buildings requiring additional life-safety measures, an optional EW 30 fire-resistance class can be specified, allowing the system to be used in fire-rated facades and on safe evacuation routes — a capability rarely available in slim-profile systems of this type.
Concealed hinges and the complete absence of plastic caps are not merely an aesthetic choice: they express the engineering philosophy behind SlimLine 38. Every visible surface presents a clean, high-quality aluminium finish that reinforces the system's precision and durability. The aluminium profile is UV-resistant and retains its colour and geometry throughout its service life without repainting, re-sealing, or structural intervention.
SlimLine 38 Reynaers is an outstanding choice for restoring buildings with historic steel window frames, where planning requirements dictate that new windows must replicate the narrow lines and industrial character of the originals while meeting contemporary energy-efficiency and safety standards. It is equally well suited to new-build projects — contemporary private homes, loft apartments, boutique hotels, offices and cultural institutions — anywhere the design intent calls for a refined, understated aesthetic.
Logi24 supplies and installs SlimLine 38 Reynaers windows across Europe. Our team provides full project support — from initial specification and design variant selection through to delivery, installation and warranty service. Contact us for a detailed consultation and a cost estimate for your project.