Like anything else, there are a number of factors and cost drivers that go into the price of constructing a steel building. In general, larger buildings cost more to erect than small ones, but you can’t base your estimate merely on how many stories or how much square footage you plan to build.
Let’s take a look at some of the things that impact the price of constructing a steel building so you can get a better idea of what to consider when the time comes.
estimating the cost of erecting a metal building
Briefly, you have tools available to you in the early design phase that help give you a ballpark of the cost of the completed building.
- Cost models
- Historic costs
- Elemental costs
Consult an experienced contractor or building designer for assistance. Elemental costs include the structural frame and is expressed as the rate per meter squared (ex. kg/m2) based on the gross internal floor area (GIFA).
Key cost drivers of steel building erection
Four areas contain the key drivers of the cost of metal building construction.
1. Function, industry sector and height
You can use your industry sector as one basis for determining cost; you can get a general idea by researching recent construction within your sector to find out how much similar buildings cost to erect. Each sector tends to have a typical frame cost tied to the floor space required.
How the building is to be used influences the design loadings under consideration by the structural engineer. Also, the function of the building often determines the clear span and floor-to-floor height requirements.
Finally, frame weight has an impact on cost, and the weight varies according to building type. A low eave industrial warehouse frame may weigh less than a long span office building. Because fewer columns are required in long-span construction, the spanning beams and steel sections tend to be heavier than otherwise.
These factors must be clarified and confirmed by the structural engineer from design assumptions and principles.
2. Site conditions, form and complexity
Form and function determine the complexity of building design. Depending on the form of the building, the regularity of the grid and the structural integrity impacts cost. You will pay more for a building that uses non-standard sections and connections.
Anything that adds to the time and effort of fabrication and installation will increase the price of the building. Tolerances and interfaces must be carefully planned and executed for non-standard sections. Retention of a facade, whether there is an adjacent building, and the condition of the ground are other factors driving the cost.
3. Access and logistics
Obviously, there will be differences between constructing a building in a large, empty space and erecting one in the middle of downtown amid other buildings or residences.
In the more crowded scenario, you may be facing restriction on work hours, extending the time it will take to assemble your building. You may be required to put noise abatement in place, another extra expense. Access for cranes and deliveries may be tricky and require different permitting or delivery methods.
4. Risk and procurement
Finally, you cannot predict the cost of materials, including steel. So much depends on the prevailing economic conditions and the fluctuation of prices throughout the economic cycles that it can be impossible to forecast accurately.
Changes in government administration and issues with trading partners can also raise or lower prices of various commodities worldwide.
Segments of frame cost
Frame costs are typically broken down into these fractions of the total:
- Raw materials: 30% to 40%
- Fabrication costs: 30% to 40%
- Construction/erection costs: 10% to 15%
- Fire protection: 10% to 15%
- Engineering: 2%
- Transport: 1%
Complex frames with high proportions of non-standard sections and complicated connections as well as specialized building systems with greater fabrication requirements increase the rate per ton over a standard frame.
Other drivers include:
- The extent of repetition in the design
- Piece count
- The type of connections
- Access to the site
Key drivers by steel building type
As we mentioned earlier, the form and function of the building are two of the key drivers of cost. Below are the details of three building types to give you an idea of what we are talking about.
1. Low rise and short span buildings
You generally see this type of building in an office park or an educational campus. The buildings need to be flexible in function and are typically divided into smaller units or rooms.
These buildings tend to have large floor plates and stand two to four stories high. The floor-to-floor heights are about 3.75 to 4 meters (about 12 to 13 feet). The uniform grid of six to nine meters provides a mostly column-free space with high floor-to-floor heights.
The average steel frame weight can be reduced by using few to no complex designs and a regular grid. The fire protection requirement for this type of building is usually lower, 30 to 60 minutes standard.
2. High rise and long span buildings
More materials mean higher costs. You need a longer structural grid span to achieve the desired open floor space, which increases the frame weight. You can use cellular beams with openings through the web to run services and maximize the floor-to-floor height. The building fit-out is also more flexible this way.
Taller buildings tend to be erected on constrained or irregular sites, which influence building form. You may need to alter the floor plates on the upper stories, creating a mixed-use scheme. All of this contributes to a higher average steel frame weight, potentially 75 to 86 kg/m2.
If you are planning anything over 15 stories, you will likely have a higher proportion of complex segments, non-standard sections, and complicated logistics. The rate may be 15% to 20% higher than standard.
3. Industrial buildings
There is a wide range of buildings in this sector - warehouses, non-food retail, distribution centers, just to name a few.
The most common form is a single story warehouse with some office space on the first-floor mezzanine. The flexibility of the interior space is a priority as is regular column spacing and long, open spans. Fire protection requirements vary with location.
The story height of a warehouse may have the same gross internal floor area but will be more similar in weight to a high eave building with a higher frame cost and a higher number of upper floor areas and mezzanine levels.
Size, function, complexity and location are all major impacts on the price of erecting a metal building. Besides the building design, you are also looking at prices for material, labor, and location, all of which fluctuate from region to region and over time.
However, you are using durable, strong steel for your structure. You will quickly achieve the return on your investment with savings on maintenance and utility costs for decades to come.