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What are the benefits of steel framing compared to…

What are the differences between Wood and Steel Frames?

When completing home renovations or a building project, you will need to consider what window and door framing materials to use. There are four main options, although this article will focus on two: wood and steel framing. Both are popular options offering an array of great characteristics.


Slim Steel Framed System

At Mondrian Glazing, we produce steel and aluminium framing. We are passionate about glass and creating beautiful, bright living spaces. Although we do not manufacture wooden framing products, we believe that you deserve to make an informed decision about your windows and doors.


The popularity of wooden frames has persisted throughout history to the modern-day, formally through necessity (as the only option for many), latterly through its respected characteristics. However, does it compare to steel?





One of the most defining features of wood is its appearance; it has a natural, organic look. Due to its prevalence throughout history, it is considered useful when completing renovations on period properties as it maintains the dated aesthetics of the building. This is also similar to steel, it is also a very suitable option as it has been used throughout history, albeit a more recent history – it can still provide a vintage aesthetic.


Overall, steel offers more aesthetic options because of its strength. It allows for more intricate designs with more glass and smaller sightlines in the frame. The use of glazing bars offers a vintage look that will last significantly longer than wood.



Thermal Efficiency

Wooden frames are natural insulators due to the air pockets in their cellular structure. They prevent the heat from transferring quickly. Steel is naturally a conductor of heat, which means that heat will transfer from one side to the other.

This is not the most useful for exterior use; however, Mondrian have thermally broken steel glazing systems that utilise the lasted advance in thermal break technology to offer a much higher thermal performance than timber. 

Thermal break technology means that an insulating piece of plastic is installed into the frame, preventing heat transfer and substantially improving the thermal efficiency. Thermal break technology can perform better than other options like wood.

Both systems have a high thermal efficiency when steel is thermally broken. Steel is more effective when reducing the use of extra energy and is better for the environment thanks to its recyclable nature.



glass and steel framed staircase

If wooden frames are treated with stain or paint and installed in a favourable environment, they can last up to 60 years. Sixty years is an impressive amount of time, however, it does not compete when compared with the lifespan of treated steel (up to 170 years).

Wood also needs significantly more maintenance and care. Many problems arise in wood that are considered “silent killer,” which is discussed in the next section.

There are three main issues with wooden frames: rotting, insects, and warping. Stains and paints chip or wear away over time which can cause significant issues for the integrity of the frame.  Steel is not influenced by warping or insects but experiences a particular type of degradation called corrosion.



Wood is the only framing resource harvested from a living organism; the fact that it is a soft tissue means it is susceptible to being broken down by bacteria over time and rotting away. The best way to prevent that is to treat the wood; this can be done by painting or staining the material. One of the most significant issues with rotting is that it could be breaking down the structural integrity from the inside, meaning it is not always noticeable until the frame has been compromised.



As mentioned above, wood originates in an organic environment; this results in many insects relying on wood for habitation or consumption. There are an array of beetles, termites and ants that will damage wooden frames creating inconsistencies in the frames. Any holes created will result in reduced thermal efficiency and could influence the quality of the structure.


The final disadvantage of using wood is that it is more prone to warping over time due to moisture. The wooden fibres in the window frame do not always dry collectively; some take extended periods of time. When moisture is reduced, the fibre begins to shrink. This causes tension and results in warping. Overall, wood is not as weather-resistant as other options. The environment has a direct influence on the lifespan of wooden frames.


Corrosion is caused by wet conditions and oxidisation. The process breaks down the steel over time and negatively influences the structural integrity. Corrosion can be prevented by treating the steel; one of the most popular is galvanisation, it is steel with a zinc coating that extends the lifespan of the steel up to 170 years.



Many people like the look of timber framed glazing systems but with the issues of maintenance and potential issues later down the line, steel is by far the better option.

fixed screen to reception area

Both materials discussed have their benefits and setbacks; but the benefits of steel framed glazing outweigh the benefits of timber by far. Steel is not only more durable, but does not encounter any of the ‘silent killers’ that can ruin wood framed glazing.


The steel aesthetic is also extremely flexible in design. Mondrian can utilise glazing bar designs and frame finishes to create systems with an elegant or industrial design depending on the type of project and its requirements.


Mondrian Glazing offers steel framing and focuses on providing exceptional quality products that last a lifetime. We offer bespoke glazing systems for both residential and commercial products; if you are interested, contact us at Mondrian Glazing.

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A Guide to Different Types of Steel

What are the different types of steel, and what are their uses?

There are many types of steel products and finishes on the market, each having different characteristics; this article is designed to collate the necessary information about steel finishes and work as a comprehensive guide. The focus of this article will be Corten Steel, Galvanised Steel and Stainless Steel. It will cover how each type of steel is made, their characteristics and their sustainability.

Steel is one of the most essential materials to construction, architecture and engineering and is one of the most widely used metals in the world. It is strong, recyclable and overall extremely versatile. So, what’s the catch? Steel can be prone to corrosion – this is when the oxygen and water molecules cause a chemical reaction on the material’s surface, breaking the steel down over time. However, this is easily overcome by adding a protective finish to the steel.

Mondrian Glazing offers all three of the aforementioned steels and finishes for the steel-framed windows and doors we manufacture. We are passionate about creating exceptional glazing solutions aesthetically and functionally. Combating weathering successfully is critical to the longevity of the Mondrian products lifespan.


Corten/Weathered Steel

Steel framed arched doors.

The name Corten is derived from the two main properties of Corten steel, “cor”-rosion resistance and “ten”-sile strength. Corten steel refers to a type of steel that possesses a resistance to atmospheric corrosions like “oxidisation”.

This resistance is due to how the Corten is formed. The first step of creating Corten is the hot rolling process. The steel passes between rollers at very high temperatures, whilst this happens, the iron waste material moves to the surface – this is the protective barrier developing.  Occasionally extra alloying elements are added (copper, chromium and nickel) which aid in the development of the protective barrier.

The iron waste materials and alloying materials creates a rust that congeals on the surface of the steel. The iron waste and added alloying elements form a protective barrier, preventing further rusting of the steel underneath. 

Many providers offer pre-weathered Corten; this is a valuable feature as this prevents runoff of the Corten staining other surrounding materials. Once the outer iron waste layer has corroded away, the material develops a more stable surface with minimal staining or shedding.

The process of creating a protective barrier saves the initial cost of painting and the maintenance costs for repainting. The Corten also changes colour over time; the colour is slightly dependant on the environment but, over a 40 year period, it starts off as a bright orange-yellow and develops to browning-black colours.  The Corten also has an almost regenerative ability; if some of the protective layer is removed, the Corten will regenerate, and a new layer will form over the exposed area.

Steel is known for its sustainability; due to its strength, it can be recycled countless times. The Corten finish increases the lifespan of the steel, increasing its sustainability further, as resources are needed less often for recycling. Depending on the thickness of the steel and weather conditions, it can last up to 150 years.

There are many benefits of using Corten steel, although it should be avoided for projects less than one mile from the beach as the high levels of salt and moisture in the air can negatively impact the protective layer. When salt and moisture are continually deposited onto the steel surface, it tends to maintain a continuously damp environment; this produces the rust product Akaganéite, which in high concentrations can hinder the development of the protective oxide layer. 


Galvanised Steel

external steel framed double casement doors

Galvanisation is another form of creating a protective coating for steel. The process is relatively simple; the premade steel is submerged into a zinc coating solution approximately 680 degrees Fahrenheit. After the steel is removed from the Zinc bath, it is cooled, and a chemical reaction (oxidisation) occurs. This reaction causes the Zinc to bond to the steel; and forms the protective seal.

The new surface appears to have a crystalline finish or spangled finish. Although if this finish does not always meet certain aesthetic requirements, it can be painted to suit specific design requirements. For the best results products designed for galvanised steel must be used, manufacturer’s instructions on application must be followed and the steel must be sufficiently primed.

One of the benefits of galvanised steel is that it is ideal for marine applications as it is resistant to all types of weathering. It has proven to be extremely reliable in both coastal and urban environments because of its corrosion resistance.

Galvanised steel is very sustainable; it is suggested that the sustainability of galvanised steel is almost unmatchable. This type of finish increases the life span significantly, lasting up to 170 years. Galvanised steel is also very low maintenance.


Stainless Steel

Steel Framed Windows

Stainless steel is formed when raw materials like Iron ore, Nickel, Chromium, Silicon, Titanium, Niobium, Manganese and Carbon are combined. There are many varieties of stainless steel as the chemical makeup of the steel influences its capabilities.  The ratio can change how strong the protective oxide layer is, its strength, melting point, and how resistant it is to specific corrosives.

The raw materials are heated to their melting point and combined over a 12-hour process in an electric furnace. The excess carbon is removed through a vacuum process and sometimes stirred to distribute the raw materials evenly throughout the stainless steel. As the steel cools, it is then rolled; this can be either hot or cold rolling to create a rough shape. It is cut, shaped and then the surface is grinded down to remove impurities and make the steel smoother.  Once smoothed, they create a powerful alloy that is resistant to corrosion.

Stainless steel can be painted, although, there is an issue with the cohesion of the paint. As stainless steel is almost completely smooth, the steel must be cleaned and primed adequately, or the paint will not successfully bond to the surface. Using the appropriate products designed for stainless steel will result in the successful application. 

Stainless steel is considered the “green material” in the construction sector; its recovery rate is close to 100%. It is also easy to clean and considered a “hygienic material.” Stainless steel is also easy to maintain. 


Each type of steel or steel finish discussed has its own benefits and qualities, whether it be aesthetically or functionally.

Mondrian’s experienced team of technical advisors are on hand to answer any steel related questions and to discuss our high-quality steel framed glazing systems in more depth.

If you are interested in any of the steel finishes discussed or are still unsure which type of steel is best for your project, get in touch with the team today.


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Steel framed-glazing or aluminium-framed glazing?

Advantages of using steel-framed glazing over aluminium-framed glazing

When searching for new windows or doors, there is a lot of information to absorb and a lot of jargon that can be hard to understand. This article has been written to try and summarise the pro’s and con’s of each in a way that’s not confusing to the reader. Both Aluminium and Steel framed glazing have excellent characteristics, so the decision is entirely dependent on the needs of the building.

What is the difference between aluminium and steel?

industrial style steel framed doorsAluminium is the most common metal globally and extracted from bauxite ore; it is not naturally occurring. The aluminium oxide goes through a process called electrolytic reduction (an electric current is sent through the material, removing other components of the aluminium oxide), creating pure aluminium.

Steel is considered one of the world’s most important construction materials and originates from Iron ore. Oxygen and other impurities need to be removed from the iron ore to create steel so, the iron is combined with carbon dioxide and a few other elements in a blast furnace-basic oxygen furnace or an electric arc furnace. After the removal of the Oxygen and impurities, steel is created, cast and rolled.  The steel used at Mondrian Glazing also goes through a process called galvanisation. Galvanisation adds a protective zinc coating to the steel; the steel is submerged in a bath of molten hot zinc. The method of galvanisation prevents rust and prolongs the overall lifespan of the steel.

So, what are the functional difference between steel and aluminium frames?

Strength and Sightlines

One of the main differences between steel-framed glazing and aluminium framed glazing is strength; overall, steel is three times stronger. The increased strength of steel-framed glazing allows for more intricate designs compared to the aluminium framed alternative. Steel windows and doors can be significantly larger with smaller sightlines (the visible areas of aluminium or steel around the door or window). This means that it is easier to create expansive panoramic views and invites a vast amount of natural light into a home, restaurant, or office. Due to the strength of steel-framed glazing, arched designs for windows and doors are usually an option with steel framing. An example of the sizing difference is our Mondrian Glazing steel framing; sightlines start at 47mm compared to our smallest aluminium frame starting at 120mm.

Weight and Accessibility

mondrian belgium door

Complimenting the pre-existing aesthetics of a home or commercial project is essential when choosing what metal frame is best, as there is quite a difference in the look and feel of aluminium and steel-framed glazing. Many argue that the look of steel framing cannot be compared to any other metals. Many architects prefer the weight behind the steel framing as it provides a more sturdy, stable feel. Steel is heavier than aluminium overall, meaning the doors and windows will take more effort to open and shut. If accessibility is a concern, lighter aluminium framed doors and windows will be significantly more suitable than the steel counterpart as they are easier to use. 


Design and Aesthetics

Another consideration when choosing window or door frames is the range of colours available; fortunately, both aluminium and steel frames have the same range of RAL colour options as any PPC RAL finish can be applied to either frame material. If intricate designs are more of an interest, then steel framing allows for arch designs rather than the regular rectangular/square shape of windows and doors. Both options also allow bespoke glazing bars.


The galvanised steel has a protective coat and has a lifespan of 34-170 years. Wiping down the steel will prevent the chemical compounds from reacting and causing rust in the future.

 Aluminium framing is cheaper in comparison to steel and does not rust but, overall, has a shorter lifespan. The lifespan for raw aluminium is 30-60 years, excluding the paint finish. Although it is unlikely for aluminium not to have a paint finish, this further increases its life span by up to 20 years. The paint coating used at Mondrian glazing is a polyester powder finish and is known for its resistance to chemicals, corrosion and weather.

Fire Resistance

Mondrian CWS-50-Slim Frames

Safety will be a priority for many when deciding on what metal to choose. Both steel and aluminium frames are non-combustive, so the metals are incapable of igniting and burning when subjected to fire. However, steel has a greater fire resistance due to the higher melting point of around 1500 degrees, so it is often the base material for fire rated installations.

 When a Steel is fire-rated, it means it prevents the fire and some smoke from spreading quickly. Steel doors can last from 30-240 minutes under fire temperatures depending on the system.

Aluminium framing is not known for its fire-rated capabilities and is not used for fire-resistant systems. This metal has a melting point of around 600-660 degree celsius, so is not suitable for these important installations.

How sustainable are aluminium and steel?

Overall, steel accounts for 7-9% of all global emissions and aluminium accounts for 3.5% of global emissions (Less aluminium is produced, meaning it is no more sustainable than steel production). The initial creation process of aluminium and steel leaves a lot to be desired when considering sustainability. However, many argue that if the metals are kept in reasonable condition, they can be recycled and reused many times, resulting in a reduced carbon footprint.  A positive is the recycling process has a significantly lower energy cost; aluminium only uses around 5% of the energy required during initial production.

Both aluminium and steel frames can be thermally broken; this reduces the amount of heat that escapes from the windows and doors. Thermally broken metal saves energy, cost and is sustainable.

 Steel and aluminium framing is more sustainable when compared to other materials commonly used for frames. The steel and aluminium frames last longer than timber framing and can be recycled more times than timber and plastic options. Plastic options last from 20-25 years, and timber frames last for up to 60 years but are not commonly recycled as many times as iron and aluminium can be.


Cost is a defining factor for many when choosing the right door or window frames. It is well known that steel is a more expensive raw material, and galvanisation (required to provide a non-corrosive finish) further increases the price.

Typically, thermally broken steel-framed glazing is three times more expensive than an aluminium alternative. However, there is no comparison for the strength and aesthetics of steel.

It will depend on what is important on the project (design or cost) as t what the best solution for each specific project. If aluminium is preferred, we recommend the Sieger Legacy range, which offers a minimal steel design but in an aluminium frame. (please note that size and weight restrictions apply due to the lower strength aluminium).


 If you are interested in adding steel or aluminium framed windows or doors to your residential and commercial project, contact Mondrian glazing.

Steel door system Technical

Thermally broken steel frame

What is a thermally broken steel frame? 

Steel is considered one of the most crucial materials globally because of its popularity in construction, architecture, and engineering. The popularity of steel can be accounted to its versatility and unparalleled characteristics. Steel is three times more robust than aluminium and has a melting point 900 degrees higher, totaling 1500 degrees. Due to its strength, it can be reworked many times, meaning it is more sustainable than other framing options like plastic. Steel is also non-combustive; this means it is incapable of igniting and burning when exposed to fire. It can also be subjected to weathering and survive for many years without buckling and warping. Granting it does need small amounts of maintenance to prevent chemical compound changes that cause rusting.

patinated antique look Windows

Steel framing has many fantastic qualities, including its strength, durability and resistance to fire. However, there is some room for improvement in regards to the natural thermal performance of a steel frame due to steel’s low thermal mass.

 A low thermal mass means that the material is heat conductive, gaining and losing heat very quickly. Heat loss can happen through convection, conduction, radiation, mass transfer, or any combination of these.  As much as 49% heat lost during winter and up to 87% of heat gained during summer comes from the windows/doors. Even with double glazing, the conductivity of steel framing hinders the system’s overall performance (The Uw value).  With the costs of energy increasing and modern thermal performance requirements/ building regulations changing, people are striving to become more energy-efficient.

So, how do we improve the thermal performance of steel in consideration of its conductivity?

Architectural Bronze Patination - Shopping centre AntwerpThermally broken steel framing is the answer to this issue. A thermally broken frame divides the steel frame into two pieces, separating the interior and exterior, joined with a less conductive material. This material is most often reinforced polyamide or polyurethane plastic which is significantly less thermally conductive than the steel frame, (insulating 500 times better than aluminium alone). The polyamide barrier reduces temperature transfer across the steel framing and ensures the system achieves modern thermal performance values. A thermally broken frame should be used in conjunction with an insulating glass unit with Ug value 1.1 W/m2K as a minimum.

Another benefit of thermally broken framing is the prevention of sound pollution. The break in the frame allows for less sound to travel through the windows and doors, meaning a quieter interior. It is especially useful if the building is close to a busy road or school, for example.

What are the issues of using Non thermally broken systems?

internal glass pivot door with slim steel frames

The use of a non-thermally-broken steel system for an exterior window or door can lead to both freezing in colder months and condensation build-up internally on the cold metal surfaces. The build-up of water residue can lead to mold and damp issues on the internal building finishes, such as wood flooring and curtains. Mold exposure not only damages the interior of the building but also leads to an array of long-term health issues if not removed. Thermally broken steel framing prevents mold-induced health problems and prolongs the system’s life while being more energy-efficient.

Non thermally broken steel-framed glass structures do have their uses in the internal spaces of a building. Many prefer the heat being able to travel through the inside of a building which non thermally broken frames are perfect for. The windows are also a great alternative to walls, as they allow more light into rooms. They work very well in commercial projects like offices or restaurants.

If you’d like to find out more about our Mondrian Glazing thermally broken steel framing for windows and doors, contact us.