Q & A

Not Rigid Enough

Whilst some SWP columns may appear  not rigid enough in their unused state, once they are put in place and filled with concrete they are more than strong enough to support an evenly distributed internal pressure caused by concrete.  In the initial marketing of PVC column formwork many contractors had expressed this doubt but once test columns were poured or trials on site were conducted this doubt was eliminated.

Will Require Too Much Bracing

Effectively SWP requires no more bracing than any other formwork system.  The bracing is not required to add strength to the formwork but to ensure the formwork does not bow away from the steel reinforcing (this usually only applies to quite tall columns).

Require Too Much Care in Handling and Storage

This is not a valid complaint and will not be raised very often.  Obviously SWP must be secured when stored on a windy site but it can be left in the weather, have objects dropped on it (up to a certain degree), etc. unlike most other formwork systems.

Spiral Marks Left On Column

Unlined SWP Column Formwork will leave a spiral mark on the inside of the column but it is a less pronounced mark compared to other spiral wound formwork.  Such lines can simply be stoned off the column.

Height of Columns

There is no maximum height apart from that of practical use, i.e. that which will fit on a truck, train, etc or that which can be manipulated on site. The important issue is the internal pressure that is being put on the formwork per hour. Please refer to following table.