"Station Construction Types - Which Type Fits Your Needs.and Budget?"

Written by: Ken Newell, AIA, Stewart-Cooper-Newell Architects

The building and design industry is a complex and complicated arena of technologies that evolve every year. There are a wide variety of construction types that are used throughout the industry by qualified owners, designers and builders. Knowing the major categories of these construction types and the advantages/disadvantages of each is important for any group anticipating a building project. Cost of construction, duration of construction, and anticipated building life span are just a few of the issues that can vary with various construction types. Your familiarity with the differences will assist you in deciding which construction type is right for you.

For simplicity sake, we will define construction types as the materials and methods used to build facilities. Probably 95% of all stations fall into one of two construction types: conventional or pre-engineered. First let's define conventional construction and preengineered construction for the purposes of today's conversation.

Conventional Construction: Defined

Conventional Construction is what most of you think about when you think of construction. Most of your homes are conventional construction. Almost all older stations are of this construction type. The site is prepared and materials arrive on site to be assembled into a building. Brick, block, studs, trusses, beams, shingles, etc., are put together piece by piece to finally evolve into a built structure. The structure includes load bearing exterior and/or interior walls.or a structural column grid throughout the building. The roof is usually supported by wood, steel, or concrete members.

City of Gastonia Prototype Sub Station: Example of Conventional Construction

Conventional Construction: Pros

• Best suited for facilities with irregular floor plan arrangements
• Best suited for multi-story buildings
• Unlimited aesthetic styling that blends will into any surrounding, including residential areas

Conventional Construction During Construction

Conventional Construction: Cons

• Load bearing walls and columns limit flexibility and future reconfiguration of interior spaces
• Historically, conventional wood, steel, or concrete structural members can have longer delivery times
• In the case of wood, the building components are combustible
• The total construction time is typically longer that other construction types

Example of Conventional Construction Wood Roof Trusses

Pre-Engineered Construction: Defined

Pre-engineered Construction typically means that major components of the building were manufactured elsewhere and delivered to the site to be erected. Most common for stations is that the structural frame of the building is pre-engineered as large, tapered columns with connected roof beams all made from heavy steel.often referred to as a "butler building" frame. When metal skins are used to form the outside walls of these large frames, the structure is commonly referred to as a metal building. However, more and more of these frames are wrapped in exterior, masonry walls or a wide variety of other finishes. The roof structure is typically heavy gauge steel purlins over the major frames.

Hilton Head Island SubStation: Example of Pre-Engineered Construction

Pre-Engineered Construction: Pros

• Historically speeds construction through shorter delivery times and faster erection of major building components
• Easily allows for large clear spans and partition walls which can be reconfigured in the future
• Is usually a non-combustible construction type
• Building cost is typically less

Hilton Head Island SubStation: Pre-Engineered Under Construction

Pre-Engineered Construction: Cons

• Best suited for rectilinear buildings with few changes in the building profile and simple roof configurations
• Requires careful planning of structural member sizing and placement so as not to conflict with building openings and clearance requirements
• Economic benefit decreases in multi-story structures
• Some of the building materials often used with pre-engineered structures have performance and longevity limitations
• Some communities are opposed to the concept of pre-engineered construction due to their perception of the construction type based on examples they are familiar with

Regarding the last item above, many laymen only know pre-engineered as buildings like "Joe's Auto Shop" down on the corner. These are often unattractive, metal-skin buildings. Pre-engineered stations can be designed and built so that the only time anyone will know that the structure is pre-engineered is when they walk into the apparatus bays and look up at the rigid steel frames.

Old Richmond Fire Station: Example of Pre-Engineered Construction

Conclusion

There are many factors to consider when contemplating your choice of construction. The decision by most Owners is usually determined by their available construction budget. Our experience has revealed that there is typically more than $25 per square foot difference in the cost of construction for these two construction types.

Both conventional and pre-engineered are valid construction types in the proper applications. Designed and built properly, the structural integrity and longevity of both types are equivalent and should be expected to provide great service for 50 to 75 years. Keep in mind that there are good and bad examples of both construction types. Don't let the bad examples of either type influence your choice.