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Internorm HF 520 – Where Timber Meets Truly Flush Design
The HF 520 makes a statement from the outside and wraps you in warmth from within – a flush timber aluminium designer window that sets a new standard for what a window can look like.
- Features
- Colours
- Options
- Specifications
- Downloads
Features
A Window Designed for Homes With Vision
The HF 520 represents Internorm at its most architecturally ambitious – a flush timber aluminium designer window that brings together natural materials, innovative engineering, and a genuinely striking aesthetic.
Flush, Frameless External Appearance
The innovative glass sash is completely invisible from the outside, creating the appearance of fixed glazing – pure, uninterrupted, and architecturally refined.Slim Frame for Maximum Light
A narrow profile maximises the glazed area, allowing an abundance of natural light to fill your interior – a feature that transforms how a room feels throughout the day.Natural Timber Interior
Inside, the warmth of natural timber – available in oak, spruce, larch, ash, or walnut – creates a finish that feels genuinely at home in even the most carefully considered interior.Concealed Hardware as Standard
No visible handles or hinges interrupt the clean lines of the HF 520. Concealed hardware is fitted as standard, preserving the integrity of the design inside and out.Triple Glazing & Strong Thermal Performance
Achieving U-values as low as 0.71 W/m²K, the HF 520 is a highly thermally efficient window that also delivers sound reduction of up to 47 dB.Pairs with the KF 520 uPVC Aluminium Window
Combine the HF 520 in living spaces with the KF 520 in bathrooms or utility rooms – maintaining a perfectly harmonious external appearance throughout your home.Colours
External Colours and Internal Timbers, Your Choice
Select any RAL colour for the powder-coated aluminium exterior, and choose your internal timber from oak, spruce, larch, ash, or walnut. A combination as deliberate and refined as the window itself.
Standard
HM113
M916
HM907
HM906
HM819
HM817
HM803
HM739
HM735
HM722
HM721
HM716
HM712
HM704
HM605
HM304
Internal
FI500
FI512
FI510
FI505
FI503
FI501
Options
Specified to Suit Your Project Precisely
The HF 520 is available as a turn, turn-tilt, or tilt window, as well as fixed glazing configurations. A thoughtful range of stylish window handles can be selected to complement your timber finish and interior scheme – each designed to sit sympathetically within the HF 520's overall aesthetic. Shading and fly screen options are available, and the HF 520 can be combined with the KF 520 for a unified appearance across your entire home.
Specifications
HF 520 Technical Specifications
Full specification data for the HF 520 is available to view below for architects and specifiers.
Specification
Material
Thermal Insulation (Uw)
Sound Reduction
Security
Locking
External Design
Interior Timber Options
External Cladding
Compatible With
Detail
Timber-Aluminium Composite
Up to 0.71 W/(m²K)
Up to 35–47 dB
Up to RC1, RC2
Fully Concealed
No visible sash frame — flush appearance
Oak, Spruce, Larch, Ash, Walnut
Powder-Coated Aluminium (any RAL colour)
KF 520 uPVC-Aluminium Designer Window
Downloads
Technical Downloads for the HF 520
Architects and specifiers can download section details, technical data sheets, and cross-section drawings for the Internorm HF 520 below.
Architecture That Speaks for Itself
Some windows frame a view. The HF 520 disappears into it. With no visible sash on the outside, it creates a façade of pure, uninterrupted glass – the kind of detail that architects and self-builders spend months searching for. It's available through Camel Glass, your Internorm partner across the South West.
Inside, the picture changes. Natural timber – in your choice of oak, spruce, larch, walnut, ash, or more – fills the reveal with warmth and character. It's a deliberate contrast: the precision and restraint of the exterior, against the natural richness of the interior. A window that rewards both the eye and the instinct for quality.
The Right Partner for Your Most Ambitious Project
Camel Glass works with architects, self-builders, and discerning homeowners on projects across Cornwall and North Devon – and the HF 520 is a product we believe in deeply. Its combination of natural materials, flush design, and genuine performance makes it one of the finest timber aluminium windows available in the UK.
Our team provides full technical support throughout the specification process, from section details and architectural drawings through to site survey, installation, and aftercare. If you're working on a project that deserves the best, we'd love to be part of it.
Frequently Asked Questions
Here are some of the most common questions we receive about the Internorm HF 520. For project-specific queries, our specialists are always happy to talk.
What makes the HF 520 different from a standard timber window?
The HF 520 has no visible sash frame on the exterior, creating a flush, fixed-glazing appearance. Concealed hardware is standard, and the aluminium cladding means no external painting or maintenance is required.
What internal timber finishes are available for the HF 520?
Oak, spruce, larch, ash, and walnut are all available, each in a range of colour treatments – so you can match the timber to your floors, joinery, and interior aesthetic.
Can the HF 520 be combined with uPVC windows in the same home?
Yes – the HF 520 pairs directly with the KF 520 uPVC aluminium designer window, maintaining a consistent external appearance while allowing different internal materials in different rooms.
Is the HF 520 suitable for a new build or self-build project?
Absolutely. Its flush design, slim frame, and concealed hardware make it a natural choice for modern and architecturally ambitious new builds and self-build projects.
How do I access technical drawings for the HF 520?
Technical drawings and section details are available to download on this page. Our team can also provide additional specification support – simply get in touch or visit one of our showrooms.
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