In Conversation with Simon Mathijssen, Managing Director of MHB steel windows & doors
For architects and homeowners drawn to the elegance of traditional steel glazing, MHB occupies a rare position: a family-owned Dutch manufacturer handcrafting solid steel windows and doors with the slender, characterful lines often associated with Crittall-style design – but with the insulation, strength and performance demanded by contemporary architecture. At the helm is Simon Mathijssen, Managing Director and twelfth-generation custodian of a company whose expertise in steel has been refined over more than 350 years.
Twelve generations of craftsmanship
Founded in 1667, MHB is the fifth oldest family business in the Netherlands. Now in its twelfth generation, the company remains family-owned – and firmly rooted in craftsmanship. When Simon Mathijssen took over as Managing Director in 2022, he inherited not just a manufacturing company, but a legacy spanning more than 350 years.
“It makes me proud,” he reflects. “We are building on a very strong foundation left behind by the generations before us.”
For architects specifying high-end steel glazing, that continuity matters. Because MHB’s story is not simply about steel windows – it is about the evolution of performance, precision and design integrity over centuries.
From master blacksmiths to hand-crafted glazing
The Mathijssen family history is grounded in traditional blacksmithing. Simon’s great-grandfather was the last master blacksmith in the family line – a reminder that today’s ultra-refined steel systems are built on years of craft and physical skill.
“I did a blacksmithing workshop myself,” Simon says, “and it is hard! It takes great skill, craftsmanship and endurance.”
That heritage is not symbolic – it still shapes how MHB operates today. Unlike many modern steel window manufacturers, MHB develops and fabricates its own solid steel, thermally-broken profiles in-house. Every profile is cut, welded, polished and finished by a highly trained team in the Netherlands.
Welding alone requires two years of specialist training.
“There is skill, precision and heavy work involved at every stage. It’s all the little things that don’t meet the eye that take great craftsmanship. Everything we do is still really crafted by hand.”
For architects accustomed to aluminium systems extruded and assembled at scale, this distinction is significant. MHB steel windows are not simply manufactured. They are made.
“When you have our windows in your home, it feels different,” Simon explains. “Compared to aluminium systems produced by extrusion, our steel windows have craftsmanship, skill and sweat built into them. And people appreciate that.”
Every window carries, in his words, “a bit of story in it.”
Reinventing steel glazing for superior performance
In the 1950s, MHB was manufacturing steel windows admired by architects for their slim profiles and aesthetic purity. But by the 1970s, the market shifted dramatically towards aluminium.
The reason was not aesthetic – it was performance. Traditional steel systems were prone to draughts, condensation and poor insulation. Aluminium, at that time, offered a more practical solution.
MHB responded differently to many competitors. Rather than compromise, the company deepened its technical expertise, specialising in fire-rated doors and partitions for commercial construction demanding high levels of performance and reliability.
Then architects began returning with a challenge: could MHB recreate the elegance of 1920s and 1930s steel windows – but with modern thermal and wind and water performance? The answer became a defining moment in the company’s history.
Responding to the architects’ challenge: a thermally-broken steel window profile
In response to demand for a high performance, insulated steel window, in 2007, MHB developed a patented thermally broken solid steel profile – a breakthrough that shocked much of the industry.
Unlike folded sheet steel systems, which can appear bulky and lack insulation, MHB’s profiles are manufactured from solid steel and thermally broken within the section itself. The result is exceptional strength combined with contemporary performance.
The innovation allowed architects to specify slender steel frames with compliant U-values – without resorting to wider aluminium sections or compromising on detailing.
“We have the knowledge and expertise and have spent many years optimising design and performance of our products,” Simon says. “We are always looking to balance design and performance.”
For more about MHB’s patented thermal break technology, take a look at our blog, What is a Thermal Break in Windows? A Guide to Thermally Broken Steel Systems.
Creating design freedom in solid steel
What truly differentiates MHB steel systems is structural capability. Because the profiles are manufactured from solid steel, they offer exceptional strength without increased sightlines. Architects can design deeper sections rather than wider ones – maintaining slim visual lines while achieving structural performance.
This opens possibilities for:
- Large-span steel doors and screens
- Minimalist contemporary glazing
- Heritage renovations requiring authentic detailing
- High-end residential projects demanding bespoke solutions
Folded sheet steel systems cannot achieve the same combination of refinement and strength. Nor can many traditional steel brands offer thermally broken profiles compliant with today’s insulation standards.
For conservation architects in particular, this flexibility is invaluable.
“We can copy historic detailing,” Simon explains. “That is very important when protecting heritage buildings. We can replicate the small details – radii, sightlines, hinge styles – so the windows look authentic, not modern imitations.”
Find out more in our blog, Why Steel Windows Are Back in Demand for Modern & Heritage Homes.
A partnership approach to growth
Despite its global reputation, MHB is not focused on rapid expansion.
“As a family business, we are not looking to actively grow fast,” Simon says. “Our focus is on quality and reliability. We like to grow slow but steady.”
For decades, MHB installed its own windows, believing that installation is the ultimate expression of quality. As international demand increased, the company shifted towards carefully selected long-term partners – companies aligned in values, capability and network.
“We work with a great network of architects and designers at the ultra high end of the market,” Simon explains. “It is a small community but we collaborate for the long term.”
UltraView is one of those specialist partners – providing UK-based architects and homeowners with local expertise, technical guidance and installation standards that reflect MHB’s own philosophy.
More than just a window system
When asked what he hopes his ancestors would think of MHB today, Simon pauses.
“I hope they would be proud of the things we’ve achieved. The fact that customers from all over the world come to us for bespoke steel windows, still made by hand in Europe – that is quite something.”
For architects and designers working in an industry increasingly dominated by mass production and who want to create something unique – choosing a real product with a real story – is a big part of MHB’s appeal.
Experience MHB systems in a working environment
Come and feel the quality and craftsmanship in MHB steel windows and doors for yourself at our new Cotswold showroom. Designed to represent a working home environment, our new space showcases MHB and Sky-Frame systems in different configurations along with smart lighting and home control systems.