What You Need To Know: Engineering Standards For Metal Buildings

When you purchase a steel Quonset hut building, you’re making an investment for years to come. To get the most out of this investment, you’ll want a building that’s engineered and designed to last a lifetime.

From energy efficient coatings to common code and load requirements, we’re answering frequently asked engineering questions customers have asked us over our decades of being in the steel Quonset hut business.

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What are Quonset Huts Made Out Of And Why Should I Care?

An arch building can technically be made out of almost any metal, but for strength, longevity, and low maintenance, modern Quonset huts are exclusively made out of steel that’s coated in an anti-corrosive agent to protect against rust.

Steel offers several advantages over buildings made from other materials. We cover why steel is better than other buildings here:

Why Does The Grade, Gauge, And Panel Depth Matter?

Three major factors that affect a steel building’s strength are the grade (quality), gauge of the steel and depth of the corrugation of the panels.

As one would expect, the thicker the steel and the deeper the corrugation, the stronger the building. But what’s equally as important is the grade or quality of the steel, which is the tensile and yield strength to help minimize tearing and deforming. Common grades range from 40 KSI up to the highest, 80 KSI.

Gauge especially comes into play when talking about the strength needed to support a location’s snow and wind load requirements. For example, if you live in an area that gets hit with heavy snow, you’ll need a thicker gauge of steel to add strength to your steel building.

What Gauge Of Steel Is Best For My Building?

The gauge of steel refers to the thickness of the panel. Though it might be a little confusing, the gauge of steel works backward, meaning the smaller the number, the thicker the steel.

This is because in the early development of the steel gauge measurement system, the one-inch thickness of steel was measured in fractions such as 1/14” thick, 1/16” thick and so on. Eventually, the bottom number of the fraction was used to describe the gauge number.

It’s important to consult with a professional, licensed engineer to determine the correct grade and gauge of steel for your Quonset hut in order to keep you and your belongings safe.

What Is Corrugated Steel (Panel Depth)?

Corrugated steel has been a popular choice in commercial and agricultural buildings for years, and has been gaining popularity in residential steel buildings.

Similar to the way a cardboard box is strengthened by a sheet of wavy paper sandwiched between two flat layers, sheets of metal can be made stronger by corrugating the material to make ridges and grooves.

Corrugated and ribbed steel panels are usually made of sheets that are shaped into ridges or waves (although some panels may have linear or square-edged shapes).

These steel sheets are made using a cold-form process, where the metal is pressed flat and then run through a process called roll forming. During this process, the sheets are cut to length, then sheets are pressured using rolling dies to create the corrugations.

Common sizes of corrugated materials can range from an extremely thin 30 gauge or a very thick six gauge. Steel buildings usually range between 26 gauge and 12 gauge.

Why Are Anti-Corrosive Agents And Coatings Important?

Any untreated material made with iron exposed to oxygen and water will rust. Since steel is almost completely made of iron, it’s the most highly man made material that is subject to rust.

When steel rusts, it undergoes a chemical reaction called corrosion. How quickly steel will rust depends on how much of the steel is exposed to moisture and air, the level of moisture and air, and whether or not any rust inhibitors are used.

Rusting will affect the outside of the steel before corroding through the steel surface. Therefore, it is important to have a protective coating to shield your metal from rusting. Galvanizing, the process of applying a protective coating to steel or iron, is important because it can provide long-lasting protection for products.

Galvanized coating is made from zinc and used to stop the formation of rust by preventing corrosive substances from reaching the metal underneath.

There are many benefits to using galvanized products for your steel building, including:

  • Saving money: While it may seem expensive at first, treating your steel building with a rust inhibitor can save you money. You won’t have to replace any parts of your building due to rust damage and save money on overall maintenance costs.
  • Little-to-no maintenance: An anti-corrosion agent will help upkeep the appearance and safety of your Quonset hut.
  • Long-lasting: You can increase your building’s life expectancy for decades by protecting it from rust with a galvanized coating, especially if your building is located in a harsh environment.

There have been many advancements with galvanization since it was first introduced in 1836. For example, the organic coating Galvalume Plus combines both aluminum and zinc alloys for maximum protection, making it highly corrosion resistant against rust.

How Does The Coating Affect The Maintenance Of The Steel Building?

A high quality galvanized coating makes the building maintenance-free, as it doesn’t need to be painted in order to protect the steel. Be sure to look for a coating that doesn’t require reapplication or the addition of varnish.

Protecting your building by painting or using a plastic coating can be impractical in the long run, because if the steel is damaged, the protective coating can fall away or chip which will make the steel to become vulnerable to rust.

Galvalume Plus is hot dipped and applied using reverse roll coaters. Then, it is thermally cured so the coating stays on the steel and provides long-lasting protection against rust for decades.

How Thick Should My Coating Be?

The thicker the coating of your rust inhibitor, the longer the lifespan of protection for your steel building. Therefore, coating thickness is one of the most important components of the quality of galvanized coating.

For example, the thickness of Galvalume Plus (AZ60/AZM180) provides a greater lifespan and corrosion protection than galvanized coated steel with a (G90/Z275) zinc coating, according research conducted by Arcelor Mittal, the world’s largest steel producer. Compared to hot dip galvanized coatings of the same thickness, Galvalume Plus has at least twice the atmospheric corrosion resistance in marine, rural and industrial environments.

Thickness helps coatings provide the ultimate combination of durability, protection and resistance against corrosion in most environments. Common thicknesses are AZ50/AZM150, AZ55/AZM165 up to AZ60/AZM180

Are Steel Coatings Oily Or Dry To The Touch? Do They Smudge?

If a coating is not thermally cured, it is more than likely going to feel oily to the touch and is more likely to smudge and show fingerprints. Galvalume coating is an example of this.

Dry finish organic coatings like Galvalume Plus provide excellent resistance to smudging and can make assembling your steel building easier, as they won’t get any residue on your hands.

This also makes assembly safer, as slippery panels are more likely to fall out of your hands.

The Ultimate Guide to Steel Buildings

The Ultimate Guide to Steel Buildings

Learn more about:

  • The features and benefits of arch-style workshops
  • Step-by-step arch construction
  • Technical specs & certifications


Disaster Resistance

Hurricane Resistant

Hurricane Resistant

Hurricane Maria aftermath in Puerto Rico

Snow Load

Snow Load

Blizzard in Whittier, Alaska

Tornado Resistant

Tornado Resistant

Tornado aftermath in Jonesville, Virginia

Earthquake Resistant

Earthquake Resistant

7.0 magnitude earthquake in Anchor Point, Alaska

Fire Resistant

Fire Resistant

Remains after fire, Hampton, Virginia


Can A Building Ever Be 100 Percent “Disaster Proof?”

While there are engineering techniques that can create a sound structure that could endure natural disasters, no building company can claim in good conscience that their building is 100 percent disaster proof.

This is because even the best engineered buildings can suffer severe damage during storms.

However, you can build disaster resistant structures that increase the chances that a building will survive a severe weather event intact.

Can My Steel Building Survive A Natural Disaster?

If mother nature can dish it out, the chances are a Quonset Hut can take it.

There are several inherent advantages that steel Quonset buildings have to protect it from the extreme weather.

The hemispherical shape of the buildings allow for wind to evenly distribute the wind load, transferring the pressure to the bottom of each arch. There is little to no chance of the roof blowing off because unlike a traditional straight wall building, there is no separate roof.

Each arch is bolted together and overlaps to ensure maximum strength during dangerous winds. Steel Quonset huts are difficult to remove from their foundations because it’s extremely difficult for strong winds to infiltrate the building’s overlapping joints.

In extreme weather events, strong winds can cause falling trees and flying projectiles. Winds can reach over 150 miles per hour and turn large objects into deadly projectiles that can penetrate a traditional building’s walls. However, a corrugated solid steel building can sustain minimal damage in the same conditions due to its extreme strength.

Are All Quonset Huts HVHZ Certified?

Not all manufacturers have their Quonset huts HVHZ certified because the certification takes time, money and expert engineering to complete. Therefore, not all Quonset huts have the quality of the product and ability to get certification.

However, certain areas like Florida’s Broward County, Miami-Dade County or the Florida Keys require buildings to be High Velocity Hurricane Zone approved.

How Does A Building Get HVHZ Approval?

The HVHZ designation shows that building products used within the zone have been tested in a lab to meet the high standards of performance under extreme stress and pressure. The conditions are manufactured according to a third-party quality assurance program.

In order to get HVHZ approval, the manufacturer must have the product evaluated for compliance with standards established by the Code by a Commission approved entity or Florida licensed P.E. or R.A.

Plus, manufacturers must also contract with a Commission approved quality assurance entity to monitor manufacturing production or have the product listed and labeled by a Commission approved certification program.

The manufacturer must submit three things:

  • Documentation on the evaluation to the building department demonstrating compliance
  • Demonstration of active monitoring of production by an approved QA entity
  • Installation instructions

Can My Steel Building Survive A Fire?

Steel qualifies as either a Type I or Type II building material and is non-combustible.

While other additions to a Quonset Hut may be flammable and subject to being destroyed by fire, the steel itself won’t burn and survive a fire.

In order to determine non-combustibility, the building material must undergo a test in which it’s subjected to 750°C (1382°F) controlling temperature for 15 minutes in an apparatus determined by the standard method of testing.

Three tests are required for each sample, and there are three criteria that must be met:

  • The mean of the maximum temperature rise of the three (or more) specimens of the sample during the test is not exceed 36o C.
  • There is no flaming of any of the three (or more) specimens during the last 14 minutes and 30 seconds of the test; and
  • The maximum loss of mass of any of the three(or more) specimens during the test does not exceed 20 percent.

When bare steel is subjected to the fire test, it will not raise the temperature, flame or lose mass, which deems it to be non-combustible.

Can My Steel Building Survive An Earthquake?

Yes, Quonset huts have withstood the impacts of many strong earthquakes with little or no damage.

A building’s seismic risk is mainly determined by its strength and stiffness. This means the stiffer the building, the less it will move or deflect when seismic waves move through the structure. Quonset huts are designed to flex, making them the best structures for earthquake-prone areas.

During an earthquake, the load is transferred to the foundation through the ceiling and walls. Because a Quonset hut is constructed as one unit, it evenly distributes the energy caused by seismic waves to its concrete foundation with little chance of damage.

The height and mass of a Quonset hut add to its ability to withstand earthquakes. A heavier building’s mass will slow down the intensity of the oscillation, which lessens the possibility of a collapse.

Since Quonset huts are typically shorter than most straight wall buildings, they may suffer significantly less damage than a taller one.

Quonset huts have 100 percent usable space, which means they do not require the use of beams and trusses to support the building. This can eliminate the potential weak spots inside of the building and few areas where the structure can become damaged, which can contribute to a collapse.

Additionally, it’s important that your steel building is engineered to meet proper seismic design regulations.  Seismic Design Category (SDC) is determined based on your geographic location, underlying soils and building use.

Soil types are determined with an A-F rating system. An “A” soil is very shallow and has hard bedrock, which is an advantage for seismic design. An “F” class soil is soft and can amplify seismic sources.

For SDC, there are two types of buildings: typical structures like offices and apartments and buildings that have to function after a seismic event like hospitals.

The seismic category assignment can also range from A-F.

  • Seismic Design Category A – Buildings in areas where expected ground shaking will be minor with good soil
  • Seismic Design Category B – Buildings of Occupancy Groups I,II and III where expected ground shaking will be moderate. Stratified soils with Good and poor soil
  • Seismic Design Category C – Buildings of Occupancy Groups IV ( Hospitals, Police Stations Emergency control centers, etc.) where expected ground shaking will be moderate and buildings of occupancy categories I, II, and III where more severe ground shaking will occur
  • Seismic Design Category D -Corresponds to buildings and structures in areas expected to experience severe and destructive ground shaking but not located close to a major fault and have poor soil
  • Seismic Design Category E – Corresponds to buildings of Occupancy Groups I,II and III in areas near major active faults in which soil or rock are of no consequence
  • Seismic Design Category F – Corresponds to buildings of Occupancy Groups IV ( Hospitals, Police Stations Emergency control centers, etc)areas near major active faults in which soil or rock are of no consequence
Can My Steel Building Reliably Keep Water Out?

Can My Steel Building Reliably Keep Water Out?

If your Quonset hut is assembled correctly, there should be no leaks. This is due to how the panels overlap and the bolt pattern that joins them.

Additionally, the washers you use are extremely important. Older buildings and some substandard steel building companies use neoprene washers, which can dry rot, don’t protect against water corrosion, and lose flexibility in cold weather. This increases the likelihood that your steel building will leak.

Can My Steel Building Survive A Blizzard?

As part of the design process, snow loads are calculated and the shape of the building allows it to stand up to snow.

Building codes first identify the ground snow load, which helps to calculate the uniform design snow load on the building’s roof.

When purchasing a steel building, make sure it follows snow load provisions required by the ASCE 7-95 and the International Building Code. Plus, check with your county or city to check for specific code for your building site.

While all Quonset hut models are usually able to be designed to accommodate heavy snow loads in areas that experience frequent snow storms, the X-Model is the most popular. This is because the X-Model has a pitched roof and slanted sides, making it easier for heavy snow to slide right off.


What Does It Mean When A Building Is LEED Certified?

The Leadership in Energy and Environmental Design certification, commonly known as LEED, is a program sponsored by the U.S. Green Building Council. The program is designed around the concept of sustainability.

There are different levels of LEED certification that building owners can achieve depending on the level that the building complies with certification standards based on five categories:

  • Energy use, including energy efficient lighting and HVAC systems
  • Location of the building and sustainability of the environment
  • Indoor air quality and use of daylight to reduce lighting costs
  • Water conservation and reduced-use mechanisms
  • Use of sustainable materials during construction

Which Building Materials Are Environmentally Friendly?

Yes. Steel is a highly recyclable material–in fact, it’s the most recycled material in the world!

Unlike other materials, steel can be recycled without losing any strength or durability, and can be recycled at any point in its lifetime.

Steel scraps can be classified into three categories:

  • Post Consumer Content – Scrap steel resulting from end of life consumer products (e.g. steel cans, steel auto bodies, building materials).
  • Pre-Consumer Content – Scrap steel resulting from the product manufacturing operations (e.g. turnings, stampings from auto part manufacturers).
  • Home scrap – Scrap produced from within the mill itself

Additionally, today’s steelmaking processes have optimized energy use, and breakthrough technologies are expected to lead to major changes in the way steel is made, according to the WorldSteel Association.  Plus, research from the WorldSteel Association concluded that the energy required to produce raw steel has dropped more than 60 percent since 1960.

Can Steel Buildings Be Eco-Friendly, Sustainably Produced, And LEED Certified?

Metal buildings can be specifically engineered to have a minimal carbon footprint and abide by LEED standards.

In addition to the building itself, there are many options for adding onto and customizing steel buildings to maximize their sustainability:

  • Using renewable resources like sunlight by installing large windows using solar-powered energy sources.
  • Utilizing high-efficiency windows and insulation to reduce energy use and increase the efficiency of the building envelope (the barrier between conditioned and unconditioned space).
  • Placing windows, walls, awnings and porches in a way that provides more natural light, maximizing solar gain and lessening the need for electric light during the day.
  • Installing on-site renewable energy sources such as solar power, wind power, hydropower or biomass to significantly reduce the environmental impact of the building and maximizing your eco-friendly building potential.

Are There Benefits To Building A LEED Certified Structure?

Absolutely. In addition to helping the environment, LEED certified buildings typically cost less to operate.

Owning a LEED certified structure may qualify owners for financial benefits through tax rebates and incentives, making them a great investment in the long run.

Buildings that use energy efficient lighting systems and low-flow bathroom fixtures can also lower utility bills for tenants, all while creating a healthier environment for occupants.

Are There Both Residential And Commercial LEED Certifications?

Yes. Commercial buildings have to meet strict standards as determined by the Green Building Certification Institute, an independent organization that conducts inspections of commercial buildings to make sure they’re following ISO international certification standards.

LEED certified green homes are designed to provide clean indoor air and ample natural light and to use safe building materials to ensure good health for occupants, according to the U.S. Green Building Council.

Like commercial buildings, residential buildings are inspected for LEED certification by an independent, third-party verification system.

The best way to become LEED certified is to use environmentally friendly construction methods, sustainable materials and energy-efficient systems into your building plans. Examples of this include:

  • Energy efficient lighting systems
  • Insulation
  • ENERGY STAR-rated windows
  • Low-flow water fix
  • Modern heat pumps
  • Energy efficient HVAC systems

What Is The LEED Solar Reflectance Index And How Can Steel Be Compliant?

The LEED Solar Reflectance Index (SRI) measures a constructed surface’s ability to reflect solar heat. It’s defined so that a standard black surface is 0 and a standard white surface is 100.

LEED requires specific SRI values for materials. Building products and materials must be tested by an independent laboratory.

ENERGY STAR requires an SRI value of 0.25 or higher for a steep slope (greater than 2:12 pitch) roofs and 0.15 or greater after three years. Low slope roofs require an initial SRI value of 0/65 or higher and 0.50 or greater after three years.

Depending on the coating, steel can be compliant with the LEED Solar Reflectance Index.