Metal homes and Barndominiums have come a long way since the post-WW2 Lustron steel and ceramic houses made to house the influx of returning GIs. Barndominiums were recalled from their humble origins as shared living and barn space on the show “Fixer Upper” by Chip and Joanna Gains in 2016. Now barndominiums are quite the trend along with their metal home counterparts, but how do they rate, safety wise?
Metal homes/barndominiums are safe despite the disadvantages of steel construction, such as corrosion and rust, susceptibility to fire, condensation, and metal fatigue. Engineering, manufacture, and design have increased their resilience to safety levels above those of standard houses.
If you are interested in how safe a barndominium or metal home is, read on as we discuss how modern design and technology has transformed metal homes into the safest homes of the future.
Potential Safety Concerns of Metal Homes and Barndominiums
A barndominium (or barndo) is a hybrid between a barn and a condominium that began its humble origins as a functioning barn with quarters above to house the caretakers of the livestock or produce. Today they range from the functional shared space of equestrians and their owners to luxurious high vaulted living areas with ample square footage to customize the spacious interiors to the owner’s whims.
Barndominiums are a particular form of metal housing alongside traditional steel homes which center around living space and do not incorporate a barn/livestock area and appear outwardly similar to traditional homes. Both, however, include the steel structure as their core design.
Most of the disadvantages inherent in barndominiums and metal housing are in the nature of the steel construction, which makes up their internal frame. Steel as a building material has many advantages, such as its strength to weight ratio and durability. However, when you consider building a steel-based home, one must be aware of the weaknesses in the steel itself and its effect on safety.
Steel Is Prone to Corrosion
Corrosion in iron and steel results in iron oxide, which we refer to as rust. Steel is made mainly of iron ore, which looks very much like rust in its dark red and grainy composition when in its natural form.
When steel becomes exposed to moisture and oxygen, its iron ore make-up tends to return to its natural state in corrosion and rust. Anyone who has seen a piece of steel in the elements for an extended time will have noted the pitted and decayed appearance.
Corrosion is at its height when a current-conducting medium links a protected metal and a corroded metal. Dissimilar metals in contact will result in one metal becoming eroded while the other remains protected such as:
- Freshly cut steel and threads on a cut pipe will corrode first
- Steel under pressure will corrode before the unstressed metal
- Where zinc coatings and steel are in contact, the zinc will corrode while the steel remains unaffected
The rate of corrosion is influenced by the climatic conditions of the steel structures environment. For steel to corrode, it needs an electrolyte such as water to conduct corrosions current to the affected metal. Rain, dew, and humidity are excellent conductors, and that is why it is essential to protect the steel structure of your barndominium in areas of high humidity and rainfall.
- Marine areas are the most at risk due to the enhanced current saltwater’s enhanced carrying capacity as a corrosion agent.
- Soil earth and clay also conduct electricity to steel structures underground
- Industrial smoke and pollutants can act as enhanced corrosion conductors, so metal housing areas in industrial areas are more at risk.
Rust can cause structural damage in steel constructions by forcing apart adjacent structures through a build-up process called ‘rust packing’ and creating torsional buckling of steel frames. To avoid weakened structural stability in your metal home, you would need to consider:
Sacrificial metals can protect the steel structure of your barndominium home by placing the steel against dissimilar metals. Metals such as zinc and magnesium are more likely to oxidize before the steel and function to protect the steel from corrosion.
These sacrificial metals may take the form of:
Galvanizing is a process that creates a protective coating of zinc over the metals that can be prone to oxidation or corrosion, such as steel. The cleaned steel is immersed in molten zinc, which hardens to form a moisture barrier. The zinc molecules sacrifice themselves preferentially to the underlying steel and halt corrosion.
This protection can also be achieved by electro-galvanization when zinc particles are given a positive charge to adhere tightly to the underlying metal.
Organic paints such as polyester, acrylic, and fluorocarbon can be sprayed and baked onto an already treated metal sheet and provide both aesthetic appeal and corrosion protection from moisture.
Acrylic and polyester paint are durable options of second coat protection and can be enhanced by silicone to deliver better corrosion resistance.
Fluorocarbon provides a barrier to heat UV radiation and chalking and lasts longer than acrylic and silicone-poly paints.
Reputable steel building manufacturers will provide a warranty that includes protection against rust and corrosion. Some companies give a forty to fifty-year warranty on their metals and finishes and a good reflection of the quality of your building materials.
Steel Is Not Fireproof
Although steel construction in your metal home or barndominium may reduce your structure’s flammability enormously compared to wood homes, it does not make it fireproof. If the temperature reaches high enough intensity, steel can weaken or fail tragically.
Temperatures of around 550℃ (1022℉) there is a marked decline in the load-bearing capacity of structural steel and may cause buckling, twisting, and eventually collapse.
You may significantly increase the safety of your metal home or barndominium in cases of fire by incorporating fire resistant strategies in the building of your home. You may achieve this through two fireproofing methods, namely: reactive and non-reactive. Intumescent paints only utilize their fireproof qualities once they are already exposed to high temperatures.
In contrast, board fireproofing and fire retardant sprays are non-reactive and have fire-stopping properties regardless of high temperatures.
Intumescent coatings provide excellent passive fire protection and extend the time that a steel housing structure can withstand high temperatures. From the Greek word “tumesco,” meaning expand or swell, intumescent paints react to high temperatures by increasing their density. They are available in a thick or thin film and can be applied by brush roller or spray on or off-site.
Fireproof boards can protect steel building columns for up to 240 minutes and steel beams for up to 180 minutes. Mineral wool and ceramic fibers can be combined with various building materials such as resin, gypsum, and concrete to provide fire resistance. These can be added to your steel house structure by cladding or drywall.
High Temperature or Mineral Wool Blankets
This form of fireproofing can work up to temperatures of 1832℉ (1000℃), and you may place it in parts of your home that are out of sight and on curved surfaces. They are also more cost-effective than other fire resistance options.
Metal Buildings Are Prone to Condensation
The cooler nature of steel in your metal home or barndominium may make it more susceptible to condensation in the form of ceiling drips and surface moisture. This moisture may occur when external warm, moist air contacts your cooler roofline or walls, or from the interior of your home via your heating or air conditioner.
This condensation can affect the safety of your barndominium or metal home by:
- Enhance corrosion even on treated metal walls and fasteners and decrease the lifespan of your building
- Affect performance of insulation
- Cause mold or mildew that creates health risks for occupants with allergies or asthma
- Allow insect infestations
There are two kinds of condensation in metal homes:
- Visible condensation occurs as frost, ice, and water and you may observe it in skylights and cooling ducts
- Concealed condensation is the more destructive form, and it arises from external air that condenses on interior surfaces at dew point or below.
This problem can be caused by:
- Roof leaks
- Lack of structural air barriers
- Incorrect vapor pressure ratios between indoor and outdoor air
- Improper insulation installment
How to control condensation:
- Ventilation balances moist interior air with the drier outside air and lowers humidity.
- Correct Insulation prevents the contact between the warm and humid interior air and the dry metal panels. Effective insulation controls the heat loss at the exposed exterior of the building, but additional insulation may be necessary for ceiling and wall cavities. Condensation points may also be painted with moisture-absorbing paint.
- Ground-level condensation control can also eliminate the effects of condensation on your barndominium. Make sure you have a well-drained base course of crushed rock or gravel under your foundation and proper drainage for meltwater or rain.
The Steel in Metal Homes and Barndominiums May Suffer From Fatigue
The steel components of your metal home are susceptible to metal fatigue. If there are variations in the tensile strength of the members, certain members may have to bear higher loads and cause a reduction in overall strength.
When steel loses its flexibility, it may become brittle and even fracture, which can damage property and occupants. The most common form of metal fatigue occurs when a steel structure has variations of tensile strength applied to them, such as a taller building such as a barndominium in a high wind area. This flaw can result in either:
- Ductile failure. This failure occurs where the component may stretch or bend before failure.
- Brittle failure is where the component breaks with little to no distortion.
Methods to prevent metal fatigue:
- Select high-quality materials with high fracture resistance
- Pay extra attention to joins and double shear joints
- Protect metal from corrosive elements
- Protect from UV light damage where possible
- Symmetry and simplicity of design
- Avoid changes in geometry on high-stress areas or openings
- Avoid metal plating with different properties to the underlying metal
- Perform maintenance and regular inspections on your metal home
Metal Homes and Lightning
Despite the myths that metal homes and barndominiums are a lightning hazard, this is, in fact, an incorrect assumption. Many people remember school science classes and the nature of metals as a conductor of electricity and assume that a metal building would be a beacon for lightning strikes in a storm.
Metal homes, to the contrary, are as safe, if not safer, than traditional homes when it comes to environmental, electrical damage. Because steel is such a great conductor, lighting is passed safely via the walls to the earth without endangering the occupant of the home. With the safe conduction of electrical current to earth, steel homes incur less damage and are less likely to catch fire after a lightning strike.
Three ways to ensure your safety in a metal home is:
- A lightning rod
- A concrete foundation
- Proper grounding
Metal Homes and Earthquakes
More and more, engineers are looking to metal homes as the solution to seismic activity and its damage to steel homes and structures. The ductility and strength of metal make it more capable than traditional structures of absorbing seismic vibrations. This additional safety can be achieved by certain structural design advances such as:
- Steel cross braces to transfer the force of seismic waves back to the ground
- Vertical walls and shear walls to add stiffness to resist swaying
- Base isolation separates the building from its foundation to absorb shock
The barndominium and metal homes are becoming increasingly popular for a good reason. Their shortfalls are solvable by careful design and focus on preventative measures during the construction of your metal home. With advances in technology, these metal homes are proving to be not as safe but safer and more environmentally friendly than traditional housing.
More and more, people have begun to seek metal homes as the solution to the destruction caused by natural disasters such as earthquakes, hurricanes, and rampant bush fires. They come close to being the safest alternative to our increasingly turbulent environment, and they also can be breathtaking in their aesthetics.
You can watch the following videos on steel and metal homes for further information:
- Wikipedia: Lustron house
- Wikipedia: Barndominium
- Wikipedia: steel buildings
- Science direct: Corrosion Damage analysis of Steel frames Considering Lateral Torsional Buckling
- CLM Fireproofing: Our Guide to Structural Steel Fireproofing
- Intumescent Paint Contractors: Intumescent Paint for Steel
- Greenspec: Insulation materials and their Thermal properties
- Whirlwind Steel: Typical Causes of Corrosion on Structural Steel and Five Steps for Prevention
- Wikipedia: Mineral Wool
- Epa.gov:Moisture Control Guidance for Building Design, Construction and Maintenance
- Designing buildings Wiki: Failure of Metals
- Ductility Review: Strength Mechanics of Materials
- Academia.edu: Lightning Phenomenon, Effects and Protection of Structures from Lightning
- Academia.edu: Analysis of Seismic Design Steel Braced Frame