Metal Building Design And Components
Metal Buildings from the client stand point is not difficult but does require some familiarity with industry terminology. Below you will find an explanation of some of these terms so that you will be able to fill out the Quote Form on this website or talk to a representative of our company by phone. While it is not required to know these terms because our representative is more than willing to walk you through the process but it is helpful.
What Type Of Building:
Are you building this for your home, a backyard shop or garage or is this more a commercial type building?
Width, Length & Eave Height of Metal Buildings:
The beginning point of any construction project is size. Specifically the width, length and height of the building you want.
Width is the measurement required from sidewall to sidewall.
Length is measured from the end wall to the other end wall.
Height is the height as measured from the slab to the eave height.
In the construction industry the width is always applied first, then the length and finally the height. An example would be a “50′(wide) x 75′(long) x 12′(high at the side)”
The roof slope (also known as the “Roof Pitch”) is the height of the roof from the edge (eave) to the top (or peak) of the roof. Most buildings in Texas have a 1:12 roof slope. That means the pitch of the roof inclines 1 inch for every 12 inches you move along the width of the building. Higher pitches are required in the Northern States to allow snow to slide off the roof more readily so as to prevent too much weight from snow encumbering the roof. You may want to increase the roof slope for aesthetic purposes, because of higher wind loads in hurricane zones or to obtain specific clearances in the end wall or inside the building.
Column shape refers to the I Beam support columns that are covered by the steel skin of the metal buildings. There are generally two types of columns, Constant Depth and Tapered. The Constant Depth column is the same width and shape from one end to the other, basically an I Beam from top to bottom. A Tapered Column narrows down from the top at the rafter down to the floor, so that the bottom is narrower the the top. The tapered column is lighter and uses less steel without sacrificing structural integrity, and because of this it is less expensive than a constant depth column after a building exceeds about 40 ft. in width. There are reasons to choose constant depth column over the Tapered Column even though it may be more expensive. One reason would be if you want to drywall the interior. The studs for the drywall are more easily accommodated for in a Constant Depth column. Your representative can help you decide which is best for your project.
Sidewall Girt Type:
A Girt is to the wall support what the purlin is to roof support. It may also be referred to a “sheeting rail” or a “belt rail”. It provides lateral support to the wall especially concerning wind loads. There are typically two kinds of side wall girts, Flush and Bypass. A flush girt system has the outside flange of the girt aligning with the outside flange of the rigid frame column. In a bypass girt system, the whole girt is installed outside of the rigid frame column with a bypass girt system. The flush girt system utilizes more of the usable floor space in the metal building. The bypass girt system, like the tapered columns, is lighter and is thus less expensive where bay spacing exceeds 25 ft. The reason for this is that bypass girts overlap each other and so provide for additional support where the column meets the girt. If you are wanting to add windows and doors you may want to move the girts up beyond 8′ so that you will utilize just inches instead of feet when framing out for doors and windows.
End Wall Girts:
Same as the Side Wall Girts only on the End Wall.
End wall Frame Type:
There are two basic types of end wall frames; expandable and non-expandable. An expandable frame is more specifically called a rigid design. An expandable end wall frame allows you to easily add doors and windows at a later date even after construction is complete. You can also “expand” the building at a later date. Of course, an expandable end wall is heavier than a non-expandable end wall and thus costs more. Non-expandable end walls come in two types, bearing and half rigid frame. The bearing end wall frame is the least expensive end wall frame type but does require additional bracing which can restrict door and window placement. A half-load end wall frame looks like an expandable end wall frame but it is quite different from an engineering standpoint. The half load rigid frame end wall is lighter because it is not designed to carry as much load as an expandable frame. While the bearing end wall frame requires X-bracing for additional support, the half load does not which allows you more flexibility when it comes to adding doors and windows.
Basically you have two choices when it comes to the overhear bay doors, Roll up and Sectional. Roll up doors are exactly what they sound like, they roll up using a chain and sprocket system. The other type is a Sectional Door which is like the doors at your home, they slide up by way of a garage door opener. You may also want a walk in personnel door in addition to the bay doors.
Again you have a choice of size, type and number of windows. Your representative will be able to help you with that.
Sidewall Bay Spacing:
Sidewall bay spacing is measured from the middle of one side column to the next column. The client doesn’t need to bother themselves with exact dimensions as the representative can advise them on that. Just let them know how many side bay doors you want and they can take it from there.
Base condition refers to the type of part used to attach the metal frame to the concrete foundation. There are four basic types Angle, Channel, Girt, and Drip Flashing. You may also combine certain elements of a few of these to provide greater pest barriers for example. Angle is the most common and comes just as it sounds, as an angle. It is most commonly used on a concrete slab foundation. Channel Bases use a “C” channel beam that lays flat along the bottom of the wall on the slab. The Girt Base is designed to be used in buildings that sit on piers rather than a slab design but may also be useful in a Slab foundation. Drip flashing can be added which can help protect from environmental factors.
Any building site is going to require a certain amount of what is called “dirt work”. This is a process that builds up, levels and compacts a dirt pad that prepares the site for the concrete foundation. You may hire someone yourself our we can do it for you, just let your representative know which you prefer.
Again you can contract this yourself or have us do it for you. The concrete foundation is what the building will sit on. There are two main types and many variations within those types. The two main types are Slab and Pier. Pier is the most cost efficient type but surface conditions and customer requirements may not allow this. A concrete slab is the most common type and environmental factors will help determine which variation is best for your building.
Primer is the coating that is applied to the raw steel as part of the manufacturing process. It is meant as an intermediary protection and lasts only a short time in building years. While in the short run it is less expensive to just have a primer coat on a finished building a Secondary or paint coat should be considered if you want to prevent damage in the long term.
These days most buildings built in municipalities require a permit based on a compliance code in order for construction to be approved by the city. The individual municipalities determine which codes they follow and may have additional local codes for metal buildings. Many counties in Texas do not have a specific code requirement but it is up to the customer to determine if a code is required. You can do this by calling the local municipality or county where the building is going to be placed. If you do not wish to obtain the permit on your own you can find a engineer, architect or a permit expediter. These can be found by simple google search for your area.