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MHB Steel Framed Windows NL Taalstraat Vught

Ultra Slim Thermally Broken Steel

  • The slimmest thermally broken steel system on the market

  • Best thermal performance testing of any thermally broken steel system

  • 100+ years life expectance

  • Large tested sizes available

  • Certified finishing options suitable for various locations

  • Wide range of bespoke metallic finishes

  • Tailor-made solutions to meet individual project requirements


The MHB SL30-ISO system offers industrial style metal frames designed to create a traditional steel design to glazing with modern performance values.

The architectural metal of the SL30-ISO profile is fully thermally broken and is available in a range of finishes in order to achieve your desired visual effect.

The SL30-ISO system from MHB is the slimmest thermally broken steel system available on the market. You are able to achieve a combined vent plus frame profile of just 50mm or a fixed steel frame of 30mm.

This minimal steel framing creates that slim framing effect in consonance with industrial loft-style buildings and art deco design. These elegant steel-framed windows and doors create a traditional element to architectural designs that create an 'on-trend aesthetic to both the external façade and interior design.

The Most Exclusive Steel System

As well as including a full thermal break and having the slimmest sightlines of any insulated steel window or door system, the MHB SL30-ISO system offers unprecedented levels of performance and durability.

It has been determined to have a life expectancy of 100+ years according to ISO 15686-2 and the steel profiles are designed for both private residential use and public-use buildings.

The slim steel frames can be used to create a wide variety of openings including typical hinged windows and doors, fixed glazing, steel bifold doors and pivoting openings.

The beauty of MHB is its ability to work outside the 'box. Various configurations have been tested and detailed. However, the project team at IQ Glass and MHB are able to help develop new and unique applications of the system to suit your project requirements. This includes larger sizes, specific opening types, and particular performance targets.

very slim steel doors to rear extension
large steel framed windows

Steel Framed Windows

The MHB Sl30-ISO system is a full thermally broken steel solution able to create a wide range of openings. 

Steel window possibilities including large steel-framed facades, slim framed fixed steel windows, side hung steel windows, top hung steel windows, vertical pivoting steel windows, horizontally pivoting steel windows* and bifold steel windows. 

The slim thermally broken steel frame of the fixed frame is only 30mm and offers the slimmest sightlines on the market. Glazing bars within the opening can be 30mm true glazing dividers or applied glazing bars in your choice of configuration. 

Opening windows can easily be integrated into larger steel-framed facades or paired with opening doors whilst maintaining very minimal sightlines. 

*Horizontally and vertically pivoting windows are available in a range of shapes including oval and arched windows. All installations are bespoke engineered on request. 


Slim Steel Framed Doors

The slim steel frames of the MHB Sl30-ISO system are the perfect solution for modern door openings. 

The minimal steel sightlines maintain a modern industrial design whist the thermal break and highly insulated glass ensure the doors achieve high levels of performance. 

Again, the steel profiles are able to create a wide range of steel door openings including single doors, double doors, large patio door arrangements, pivot doors and bifolding doors. 

The steel bifold door from MHB offers an ultra-slim sightline with just 42mm of the frame across the connecting bifold panes. 

You can easily integrate these steel-framed opening doors within a larger steel-framed MHB facade or pair them with side glazing and opening windows. The connection profiles between windows and doors are still extremely slim at just 56mm. 

MHB SL30-ISO steel framed doors on modern extension


MHB SL30 ISO steel framed glass box extension


The steel profiles of the SL30-ISO system are fully thermally broken. This allows us to achieve high levels of thermal insulation when paired with insulating glass units. 

For example, you can achieve a Uw value of 1.1W/m2K when you use double glazing with Ug value 1.0 W/m2K. All overall Uw values should be calculated individually for each project to offer accurate performance values however Uw values from 1.1-1.3 W/m2K are expected. 

The system is designed for external use and has been tested for air permeability and water tightness. Various opening types were tested with all applications achieving Class 4 for air permeability and up to Class 9A (600 Pa water pressure for water tightness). 

Thanks to the in-house R+D department and MHB they can engineer installations that achieve much higher performance than this where required. Let us know what your specific performance requirements are and we can provide the solution. 





Bespoke Finishing Options

All profiles are finished to your specified colour / finish in house by MHB. Their in-house finishing facility has been awarded the Qualisteelcoat C5 certification which ensures a high quality finish on all projects. 

There are a range of finishes available including standard PPC certified to Qualicoat class 2. This finish is classed as 'Super Durable' and are tested in accordance with ISO 2180 with a three year Florida exposure test. 

There are also a range of different finishing grades possible for inland and coastal projects 

As well as Matt powder coated finishes you can also choose from a selection of PPC finishing options with varying levels of gloss and texture. 

In addition, you can also specify a selection of special metallic finishes which offer a true metallic design including various colours of bronze. 

metal framed doors

Handle Options

The MHB Sl30-ISO system offers a range of handles for both the windows and the steel door openings. 

The handles are fully interchangeable with the various escutcheon options. 

There are 4 main handle options, all available in a straight or cranked design. In addition, window openings have 2 additional handle options in a T or L shape. 

All handles (excluding the brass versions of the window handles) are available in brushed stainless steel which can be PPC coated to match the frame finishes. 

When selecting the handles for steel doors you also have options on how to integrate the handles into the frame. Please see the datasheet for all the options and image examples.

ASK US ABOUT OUR MHB Steel Windows and Doors System SL30 ISO



MHB Steel Windows and Doors System SL30 ISO Brochure


MHB SL30 - Product Data Sheet


Video | MHB Handle Options

Technical | True vs Applied Glazing Bars