Here we talk about the technical side of the shed and the slang used in the industry. Our aim is to provide informed information to assist you in buying your new building. If you have any question please don’t hesitate to call us, and one of our staff will be happy to assist you.
What is Site Specific Engineering
Many shed suppliers will supply you with generic engineering which covers all areas with NO consideration to terrain and shielding of the building. Site Specific Engineering ensures the building is designed for your area and location giving you peace of mind and assurance that the building you purchase is fit for purpose. Many local authorities around Australia will not accept engineering unless it is site specific.
Wind speed may be referred to in many ways. W33 , W41, W50, W50C or N1, N2, N3, N4, are all super ceded methods of stating winds speed. Anyone quoting these wind speeds are not keeping up with current engineering requirements as set out by the Building Code of Australia (BCA).
Wind speed is measured in metres per second (m/s), N40 – N50 – N60 are the new wind codes all building should be designed to (example N40 = wind speed of 40 metres per second m/s).
How is strength determined
Strength of the building can be determined many ways. The rule of thumb used in the shed industry is the weight of the building. When getting quotes always ask what the weight of the building is, the kit that weighs more for the same size building will indicate it has heavier steel components than the kit that is lower in weight. Generally, the kit that is heavier in weight will be stronger and may cost more.
What is the gable end
When looking at the end of the building which shows the roof pitch, and the highest point of the building, also known as the end wall.
What is the span
Also known as width the shed span refers to the gable end of the building and indicates the width of the building.
What is roof pitch
It is the angle the roof falls from the ridge to your gutter, we use 10, 15, 20, 25 and 32.5 degree roof pitches.
What is the apex
Apex refers to the top of the roof also known as the ridge of the roof.
What is a rafter
Rafter refers to the beam that follows the pitch of the roof from the apex to the gutter, it is a major structural component that supports the roof.
What is a column
Column refers to the section that fixes to the floor with a bracket and bolts to the rafter with a bracket, this is a major structural component that supports the roof and walls.
What is the knee joint
The knee joint is the point where the column and rafter are joined by the knee bracket or knee plate, the further the bracket wraps around the column and rafter, stronger the joint is.
What is the apex joint
The apex joint is the point where the left and right rafter are joined by the apex plate, the further the bracket wraps around the rafters, stronger the joint is.
What is a portal frame
Portal frame refers to both columns and both rafters bolted together using knee plates and apex plate, when bolted together they form the portal frame.
What does length mean
Length of the building is determined by the distance from one gable end to the other gable end.
What is a bay
Bay of the building is determined by the distance from one portal to the next portal this determines the length of the building, you may have a 9m long building made up of 3 bays at 3m.
What is the height
Height of the building is from bottom of column to the top of the eave purlin along the length of the building.
What is barn height
Barn height is determined by two heights, outer wall and inner wall, the inner wall is the main body of the barn the outer walls are the enclosed awnings of the barn.
Does the roof pitch change
The roof pitches on the barn can be the same, you can also have a higher roof pitch on the main body of the barn and a lesser pitch on the awnings.
What is clear span
Clear span is the distance from column to column without any internal post supporting the roof.
How far can I span
With our engineering we can span from 3m to 24m clear span, in our standard range. With our hot rolled buildings the sky is the limit!
What is a purlin
In the shed industry the purlin refers to the roof battens, they are metal battens that span across your portals to support the roof sheets, the more purlins you have the stronger the building becomes.
What is an eave purlin
The eave purlin runs the length of the building and provides a fixing point for the wall and roof sheeting.
What is a girt
In the shed industry girts refer to the walls of the building, they are metal battens that span across the portals to support the wall sheets, the more wall girts the stronger the building.
What is a mullion
Mullions are support columns for the gable end (end walls) and roller doors. Referred to as front wall mullion and back wall mullion and roller door mullions, wall girts can only span a certain distance, the engineer inserts a mullion to share the load of the wall it is supporting in the gable ends.
What is a header
The header refers to a beam running across an opening of a window, door or roller door, used to attach sheeting and give additional strength.
Do I need bracing
Bracing is very important to the structure of your building, bracing is determined by wind loading , terrain and location of the building. The amount of bracing required will be determined by Steel Buildings Australia and the Engineer.
Do carports need bracing
Generally if carport posts are bolted on top of the slab or piers, bracing will be required, if the posts are embedded or set in the piers, bracing is not required, refer to your engineers details to determine bracing requirements.
What is TCT
TCT stands for Total Coated Thickness and is the thickness of the base metal after it is coated with colour. TCT sizes in the shed industry are as follows .42TCT - .47TCT - .53TCT. Any other size may indicate imported steel.
What is BMT
BMT stands for Base Metal Thickness and is the thickness of the material before it is coated. BlueScope BMT sizes in the shed industry are as follows: .35BMT, .42BMT, .48BMT. Any other size may indicate imported steel.
What are the flashings
Flashings are used to cover sheeting were it meets at a corner. Flashings will weather proof the building. Some companies don’t use corner flashings, they expect you to bend high tensile sheeting around the corner of the building, very expensive if you make a mistake.
What is top hat used for
Top hat is used for the roof purlins and wall girts, the span between portals and wind loading of the building will determine the size of top hat used in the building, main sizes used in the shed industry are TH64075, TH64100, TH96075, TH96100, TH120120.
What is a C or Z section
C/Z Sections are used extensively in the shed industry to make the main frame of the building and mezzanine floors, the span (width) of the building and wind loading will determine the size of C/Z section used.
What is a web frame
Web frames are much stronger than the C section frame, used to gain greater spans and additional strength in the frame of the building.
What is a UB frame
UB stands for universal beam, UB frames are the pinnacle of shed frames, very strong, the ability to span much further, commonly used in large industrial applications.
Thankyou for taking the time to read and understand what is involved in a shed, if you have any comments of how we can improve SHED TALK please send us a comment, if you have any questions, please don’t hesitate to call us.
Steel Buildings Australia