Shed – eye for detail.

Posted on : October 14, 2012

Sheds come in different types

The majority of sheds sold today in Australia are of the portal frame design and the components are what is called cold rollformed. But there are two other important types of shed construction that is becoming more popular, the structural steel frame and the stud frame sheds. This is a quick rundown on the three different types:

 

1. Cold rollformed portal frame shed.

This is the most common type of shed and is normally supplied pre-engineered and in a kit form. The main structure (called the portal frame) consists of rolled purlins, girts, batton, top hat and brackets. The cladding and flashings are common to all types.

 

Portal frame showing apex and knee brackets

Portal frame showing apex and knee brackets

As you can see the basic prinicple is that all the purlins (both rafters and colums) consist of cold rolled C section joined by fabricated brackets that bolt each assembly together. The roof and wall members are added once all the portal frames have been stood. This is a very efficient system that can be transported easily and assembled on site with minimal tools. 

 

2. Structural fabricated steel shed.

 Nearly the same engineering prinicple as number 1 – except all the colums and rafters are from hot rolled section such as H section, I beam, or C channels with welded cleats and joiners on all ends. All other components are normally the same. The advantage of this type of design is for larger spans especially used in large warehouse constructions and normally over 18 meter width.
Structural steel is a bolt together design with heavy structural steel

The structural steel is heavy to transport but does allow faster erection and extremely high strength joining system. All the other components are very similar.

 

3. Steel stud framed sheds.

 Now this is completely different to the above two. It is identical to the steel stud framing used in housing and results in a very strong overall construction. The walls and trusses are all prefabicated in sections and simply stood on site and then clad. The advantage of this system is the ease of which you finish the sheeting internally and is the reason it is gaining popularity. 

Steel stud frame shed

As you can see there are no colums protruding into the interior and all window and door penetrations are done at fabrication stage. While slightly more to transport – the erection time is greatly reduced and the finish (interior) allows much cheaper cladding solutions. It can be treated in the same way as a normal house frame. 

 

Not all sheds are the same, and to ensure you obtain one that suits your purpose contact Shedeye.

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ShedSafe – An Industry Body or A Brand – Part 3?

Posted on : November 5, 2011

Shedsafe – A Question Mark?

Just answer one question please ?

What is the Base Metal Thickness required by ASI?

This is Part 3 and only a question? Within Shedsafe terms and conditions to join the group (brand) – the above item J. is applicable.

So – Shedsafe only allows BMT or TCT approved by the ASI – THE QUESTION IS what is the answer please. How thick is the BMT in all your shed members 0.35BMT or 0.42BMT or what? The ASI has now got to answer the question.

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ShedSafe – An Industry Body or A Brand – Part 2?

Posted on : September 28, 2011

Shedsafe errors in the requirements of its members?

This Part 2 (of many to come) is basically regarding the accreditation requirements placed on its manufacturers of sheds that are Shedsafe Accredited. The first requirement that is outlined below is in regard to the thickness of the steel roofing utilised in shed construction. Prior to delving into this area – a brief explanation of the product flow is required of the steel used in the shed roof cladding .

The steel manufacturers process iron ore in a furnace to produce steel – very basic and this is then transformed into the many steel products available on the market. The roof sheet steel is in a coil approximately 940mm wide with a BMT (Base Metal Thickness) of 0.42mm which can have a Coloured paint coating or Zinc Aluminium Alloy. This coil is sold to the metal rollformers to run through a rollforming machine to get the required profile of roofing. These companies also rollform the purlins, battens, tophat, gutters, ridge cap, fascia, barge mould, gable roll and fold most of the required metal flashings. These are all rolled from an order from the shed manufacturer according to the shed being supplied. In some cases the shed reseller may be part of a large group and simply order direct from the parent rollformer.

So the rolled coloured corrugated roofing arrives on site (and all other parts) as a direct result from the customer shed order that has been designed, approved, manufactured, delivered and ready for erection. Your shed is also issued with a 15 year roofing, cladding and purlin warranty from the steel manufacturer also sometimes the parent company of the shed reseller.

Lets start with the quote to the customer from the shed reseller. You’ve given all the details of your requirements of a shed and accepted the quote. Here is a small sample of one such Shedsafe Accredited reseller that is also owned by a national Shedsafe Accredited Shed manufacturer.

 

Details of Roof Sheet Thickness

 

Notice the roof cladding is 0.40 TCT Trimdek Profile C/B. The Trimdek and Colorbond description is fine, the 0.40 TCT is the roof sheet properties – that is in this case a 0.40mm thick Total Coated Thickness or back to the earlier description is equivalent of 0.35mm BMT (Base Metal Thickness). So this is 0.07mm thinner than the normal roof sheeting that should be installed on a domestic sheds. Why do they supply this sheeting for roof materials on sheds? Because it’s cheaper and many people don’t know the difference! So Shedsafe accredited resellers and manufacturers have been through the extensive training and requirements of the ASI run Shedsafe group. In fact in one of their requirements of shed manufacturers to become accredited is the fact outlined above regarding product warranty for 15 years. Here is the item by Shedsafe that requires manufacturers and resellers to:

 

15 Year Roofing Warranty

 

So the Shed Industry Benchmark group of Shedsafe – is setting the target or requirement of a 15 year warranty and its strick accreditation process is followed by all of its members. So the sample above (a shed which was supplied in 0.35BMT roofing) will have a 15 year warranty? WRONG.

Now lets look at Shedsafe again, an industry body run by the ASI of which BlueScope is the major sponsor. BlueScope also manufacturers the steel coloured coil for these very same Shedsafe accredited manufacturers and resellers. So lets examine the warranty for 0.35BMT roofing use in sheds.

 

 

BlueScope Roofing & Cladding Warranty

 

The main part in this warranty is that the supplier of the steel will not give a warranty on the 0.35BMT roofing that can be found in part 1 of the terms and conditions of the BlueScope Shed & Garage Warranty.  The basic error is that the BlueScope run ASI and its ShedSafe group have not covered all the small detail and continues to stipulate that Shedsafe accreditation is the Industry Benchmark. If they cannot enforce a simple base metal thickness that the manufacturer stipulates – what else is also wrong?

If your shed is supplied with 0.35BMT (or 0.40TCT) roofing – then it is not covered by the BlueScope warranty and the shed reseller will have to provide an independent cover for this warranty. Will they provide a 15 Year warranty on a 0.35 BMT thick roof sheet?
Accreditation is a simple word that enforces the meaning of having all the checks and processes in place to eliminate error.
This is one error that Shedsafe has to correct.
Next week part 3 – more detail of the marketing group Shedsafe!
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Concreting before or after The Shed is erected

Posted on : May 10, 2011

The following question has been posed on the Shedeye forums.

I have purchased a 6 x 6 single roller door shed that I am erecting and have to do my own slab. Some people told me it’s easier to pour the slab after the shed is built and it covers all the holes in the wall sheets. But the shed supplier told me to pour the slab first as the steel sheeting supplier warranty would be voided as direct contact with concrete rusts the sheets.

Which one is right?

Concrete, due to the high alkaline, will rust colorbond quite quickly.

Take heed as the advice from bluescope is

Erecting the shed prior to the concrete slab being poured, consequenty using the steel walling as formwork, is not recommended.  The predominant problem associated with this poor practice is accelerated corrosion due to:

  • Contact with wet cement, which is strongly alkaline.
  • Shrinkage of cured concrete enabling the build-up of dirt and debris in the gap left between the slab and the wall.

(bluescopesteel website).

In addition to the above advice, you should maintain a free drip edge, this is very important otherwise you get a build-up of water at the cut edge of the steel, and rust is guaranteed!

As always there are exceptions to the rule, and some of the best shed companies and builders do in fact pour the slab after the shed is built, the techniques used to achieve that are destined for another article!  The owner builder should stick with the advice in this article.

 

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