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.



One Response to “Concreting before or after The Shed is erected”

  1. Sheds said...

    There are plenty of techniques that are followed in an engineering tasks like these and the process followed for each one would vary some might prove to be good ones helping to complete it off within time while some might not but the ultimate approval lies with the person who is paying for the services, so asking company person to follow some specific step won’t be an issue.

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