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The modern era of steelmaking traditionally began in 1855 with the introduction of the Bessemer process which consisted in blowing air through the molten iron to speed the process of oxidation and removal of various impurities from the metal. This allowed a production of large quantities of quality steel at an affordable rate. Steelmaking was further improved in the 20 th century by the Linz–Donawitz-steelmaking method, better known as basic oxygen steelmaking (BOS), which today accounts to roughly 60% of all global steel output. Most of the other 40% is produced by the Electric Arc Furnace (EAF) method that heats charged material by means of an electric arc. Although both methods use large quantities of recycled scrap metal, the EAF method is particularly useful in its capacity to produce steel from 100% recycled scrap metal, while the BOS method always requires a certain minimum amount of metal ore content to start with.

This makes modern steel one of the highest recycled materials on the planet. Today recycled steel accounts for over 85% of used material in global steel production. This has reduced both the need for large scale iron mining operations and the need for some countries to import iron ore at a high cost, bringing key economic and environmental benefits.

After steel is produced by either the BOS or EAF method, there is still the possibility to improve or adjust its properties depending on different needs. What’s known as secondary steelmaking, is a key part of modern steel production. The final composition and properties of steel can be adjusted by processes such as deoxidation, desulfurization, degassing, decarburization, allowing, trimming additions, as well as heating and temperature adjustment. When a desired consistency has been achieved, the next step is casting, followed by forming the metal into a desired shape by methods such as hot rolling.

Although the steel now has the required shape, hardness, and consistency, it still requires protection from rusting. At this point, an additional step is required which is particularly pertinent to metal roofing, namely galvanization – the application of a protective zinc coating to the metal. The most common and effective method of galvanization is what’s known as hot-dip galvanization. In this process the steel strips are cleaned from any oils and dirt with a caustic solution. The solution is then rinsed off and the steel is pickled in an acidic solution to remove mill scale on its surface (iron oxide) and rinsed again. A flux of zinc ammonium chloride is then applied in order to inhibit oxidation. The steel is then dipped into a molten zinc bath and held there until its temperature equilibrates with the temperature of the molten zinc.

After the temperature settles, steel is removed from the bath, the zinc layer is blown off by air wipers until the desired coat thickness is reached, and the metal is cooled in a quench tank. Among other layers, the most important is an application of a chromate layer to prevent ‘white rust’ (caused by the oxidation of the zinc coating). The final step is to inspect the steel strip, oil it, cut it at desired length, and to coil it.

Galvanized steel has some extremely useful advantages over other metals, including different types of steel. Common metal roof providers in today’s market use poor quality non-galvanized steel. The only protection from rust is a coat of paint that, with time, can easily crack and expose the underlying steel. The advantage of galvanized steel is that the steel is not just coated in paint, but an extremely durable layer of zinc that binds with the steel itself. Even in cases where the inner steel is exposed, protection can continue because zinc is close enough to be electrically coupled. Thus, rusting on exposed and cut edges does not occur as it would on painted non-galvanized metal sheets. No non-metallic coating can provide the same protection as zinc coating. Furthermore, galvanized steel provides outstanding resistance to any mechanical damage and will rarely require maintenance. Finally, its main advantage is that the cost is simply unbeatable. Getting a copper, aluminum, or stainless-steel roof is extremely unpractical because it is extremely expensive and these metals do not provide any benefits over a much more affordable galvanized steel option. Thus, a galvanized steel roof is simply the best cost-effective option in today’s metal roofing market.

The process of developing the materials and delivering them for a particular project can be separated into different steps. Developing the materials includes manufacturing a certain number of metal panels and custom-made flashings, as well as assembling any additional metal and non-metal accessories, such as screws, vents, lumber, membrane, roof boots, hermetic, sealant, etc.

The process of manufacturing starts with a roll-forming machine. We use a US produced one-sided computer-based machine. The roll form line with PLC (programmable logic controller) is intended for serial production manufacturers. PLC allows to configure the speed, number and length of panels. The material (in the form of separate sheets) is placed into the slot and pushed further towards the rollers that shape the final properties of the profile. Also, there are gauging rollers that give the material needed thicknesses or stiffness, optional rollers for semi round or trapezoidal ribs, and composite rollers that form a damage-resistant polymer coating.

The machine presses and shapes metal at room temperature while the material goes through several stations.  Each station of rollers presses the steel with slightly more force than the preceding one. At the final stage the panel undergoes straightening, relieving the pressure, and cutting according to a predefined length. Finally, the product is manually moved aside.

For the manufacture of flashings, we use manually adjusted on-site roll formers and benders. A big part of this process relies on semi-automatic and manual bending machines. The metal brake allows to have perfect folds for long lengths of flashing. Different types of flashings have slightly different dimensions and require certain steps (folds) in order to produce a proper form. For a number of projects, standard sizes do not fit and additional measurements require customization to specific dimensions. Usually, this process has to be done manually.

Lastly, additional metal and non-metal accessories are collected. Metal panels, flashings, and additional accessories are collected and are loaded for transport. Delivery includes transporting the materials to the project site and safely off-loading the materials at a convenient location for the property owner and the installation workers. Our delivery crew makes sure that materials are delivered and stored in a such way that prevents any potential damage to the property.

Furthermore, after the work is finished, our workers make sure to do an extremely careful and diligent job cleaning the site from any left-over materials.

Area of a triangle = [Base x Height]/2

Area of a trapezoid = [(Sum of two parallel sides) x (height)]/2

Once the measurements are made, the formulas are used to calculate the areas, and the totals are added for a final amount.

The second method involves measuring the roof in divisions of rectangles and triangles using Google Earth software. Following this, one then uses mobile applications like pitch gauge and the street view function on Google Maps to measure the pitch of the roof.

The next step is setting the cut-level. This determines the waste factor and difficulty of the project. Waste factor can range from Cut Level-0, when practically no waste of material occurs, to Cut Level-5, when up to 25% waste occurs. Once the measurements, pitch level, and cut-level are inputted into the application for each division of the roof, these totals are then added and an estimate of the square footage of the roof is obtained.

We must note that because satellite image measurements are never exact, the formulas used by the application give only an approximation of the square footage and can range anywhere from 80-90% in accuracy.

However, this is still the most common method used by roofing companies to give potential customers quick estimates without the need to visit their property.

The third method is used exclusively by professionals in the roofing industry. Initially, there are two options to pursue this method. The first is to obtain blue prints or architectural drawings that include the pitch for all sections of the roof as well as measurements of all the sides from a top-view point.

The second option is to use high definition aerial view pictures captured by a drone. This also requires getting an accurate in-person measurement of one side of the roof as well as the pitch levels for all sections of the roof. The measurements are ideally performed using a laser measuring tape and a Smart Protractor mobile application. After one obtains these measurements, they are inputted into a sophisticated computer software program like Eagle View or iRoofing, which can process the information and determine the area of the roof with 100% accuracy.

Furthermore, they can also help determine the dimensions of additional accessories that will be needed to complete the project. This method is used by roofing professionals specifically because it gives an extremely accurate estimate of labor and material costs of the project, while requiring little time and effort.

As mentioned earlier, the waste factor is one of the key elements in determining the price of a project. When installing a metal roof, the panels have a certain amount of overlap. Furthermore, the metal panels are standard sized and always need to be cut to custom lengths according to each project. This indicates that the area of the roof will always be less than the total area of the materials needed, requiring every estimate to take the waste factor into account, which can usually be as high as 20%, depending on the complexion of the roof. This key element is often overlooked; only true roofing professionals can individually evaluate the waste factor of a project and provide the customer and roofing company a cost base analysis that is both accurate and transparent.

What to expect from the process of installing a metal roof? To answer this question, you need to divide the process into certain stages. These steps follow a certain order and require various installation techniques. At each stage, we noted a number of professional recommendations from a roof installation profession, which we think you should know about before going ahead with your metal roof installation.

This step requires to check the availability of all the required tools and instruments for the installation, obtain the permission of the property owner to use their electricity, and determine an appropriate place for safe storage of work equipment. The responsibility of each installation team is to maintain all required safety standards and be fully informed about the work plan for every particular project. In order to complete the project in the set time period the installation team must determine if the roof contains any potential weak spots that might require additional support as well as any other relevant nuances.

Recommendation: Before any work has begun on a project, the above-mentioned questions must be discussed with the property owner.

Although removal of shingles is not necessary for metal roof installation, some removal is still required. Shingles are cut off on the edges of the roof and deteriorated shingles are usually removed, especially those in the most vulnerable areas like near vents and skylights. In order to establish proper ventilation for the roof, there is a need to cut out a ridge vent. If needed, the ventilation system can be complemented by installing metal vents, especially in the case where the ridge will not run along the entire plane of the roof, or the plane is separated from the main roof and requires self-ventilation.

Recommendation: It is necessary to establish which vents will be replaced by metal ones, and which will be dismantled at installation of the ridge venting system. If absolutely necessary, the top layer of the shingles roof should be removed partially or in full.

This stage does not require special skills or tools. Essentially, the waterproof membrane should be installed around the whole perimeter of the roof. To get the best result, the edge of the membrane should be lowered under the gutter by a few centimeters. In this case, the water that seeps under the metal (mainly from condensation) will flow down the surface of the membrane to the gutter. The presence of a membrane is the basis of roofing, since waterproof barriers are used in shingle, flat, and metal roofing industry.

Recommendation: Unfortunately, not all companies utilize the use of a waterproof membrane in today’s industry. Thus, before installing your roof with anyone, we advise to check whether the installation of the membrane is provided by the official agreement between you and the roofing company. If there is no membrane in your agreement, we strongly advise to either find an additional company for an installation of the membrane, or to find a company that includes this step in their metal roof installation process.

The key to a successful completion of this stage requires establishing a correct layout of the roof for the installation of starters – flashings that determine whether metal panels will lie flat or have gaps along the roof. If the flashing is not installed correctly, the risk of leakage increases substantially. Particular attention should be paid to the installation of ridge cups, valleys, and wall flashings. The most common problems associated with a poor installation of the above-mentioned parts are the formation of bird nests and water leakage in walls and ceilings. A professional treatment of chimneys, mental vents, and skylights during metal roof installation can reduce the risk of leakages by 75%, largely because these areas of the roof are most vulnerable to various external factors. During strapping installation, one needs to be certain that the lumber is of good quality and has no external damage.

Recommendation: The use of non-standard flashings is rare, but may be required due to the design of the roof. In order to establish a straight alignment of the roof, one needs to install the strapping in such manner that creates a straight and levelled surface, compensating for any curvature, depressions and bumps that constitute the original surface of the roof. Only a straight and levelled surface can be used for metal roof installation.

Working with metal panels requires proper marking, precise and accurate cutting, as well as a secure fastening. Proper marking allows the installer to understand the location of each panel on the roof. The cut of the panel must be precise and careful to avoid possible exposure of the metal that can lead to damage to the zinc surface and corrosion in the future. Fixing the metal tiles to the roof structure in a secure and professional manner is a mandatory element of any successful metal roof installation. Only an experienced installer can make the effort to tighten the screw to an extent that isn’t too tight (which could potentially damage the screw head or metal surface) or too loose (leaving the screw point unprotected).

Recommendation: When installing metal panels, one needs to remember to move from one section of the plane of the roof to the next only when the work on the previous one is finished. It should be remembered that although the metal surface is stable, minimizing movement plays only a positive role since there is a lesser chance of micro-damage to the metal surface.

The last stage of installation includes sealing the seams and other potentially weak points with silicone. Work on vents, pipes, skylights, chimneys require the use of silicone sealant in practically all cases.

Recommendation: Folds should always be properly lined with metal. Silicone is a very effective, but still only a further preventative measure. One should not try to compensate bad installation practices with large-scale use of silicone sealant.