CVC Columns’ formwork is made by spirally winding a continuous strip of plastic profile, locking the edges together to form a tube. It’s a fast and efficient process that results in the most convenient formwork available.
CVC Columns’ formwork is custom made to the sizes ordered. There are no standard lengths or diameters.
CVC Columns’ forms are ordered by specifying the diameter and length required. Two thicknesses of plastic profile are available, depending on the height of the concrete pour – as per the chart on this page.
Note: The rate of pour affects the load on the formwork. This chart is for the safe height of
column that can be poured in an hour. (In extreme conditions this time may vary.) Please contact our customer service team for additional information.
Two finishes are available.
Structural: The finished column will show a spiral line.
Architectural: The column forms lined with a rigid plastic sheet, providing a smooth finish to
the concrete column.
Colum formwork should not be stored in direct sunlight for long periods. Where possible, column forms should be stored vertically.
Where column forms must be stored horizontally:
- The ground must be flat, even and clear of debris.
- Formwork stacks should not exceed 15 metres high.
- Formwork made from heavy profile should not be stored on top of formwork made
from light profile.
The top and bottom of the column form must be fixed in their designated positions.
At the bottom: Typically the column form is held by 4 equally spaced blocks of wood
fixed to the floor slab.
At the top: The top of the form is usually held in place by the soffit formwork.
Where there is no soffit formwork (such as a final floor to a roof), props should be placed on the vertical bracing to position the column. A hole cut in a piece of plywood to suit the O.D. of the form and fixed around the top of the form and to the vertical bracing will help resist damage from equipment used during pouring.
Note: Forms should be placed with the arrow facing upwards.
Bracing is recommended for columns.
- 3.5 metres and longer with diameters larger than 450mm.
- 3.0 metres and longer with diameters less than 450mm.
CVC Columns’ forms are generally braced according to accepted industry practice. Bracing ensures the column form remains straight and reduces the chances of bowing during pouring, it is especially important with tall, small diameter columns.
Cross bracing is typically placed at intervals of between 4 and 6 times the column diameter.
Vertical bracing assists in ensuring the column form remains plumb and in the correct position.
Commonly 4 timbers (100mm x 75mm) for diameters below 600mm or 6 timbers (for larger diameters) are equally spaced around the circumference of the form running the full height of the column.
Props should not be placed directly onto the CVC Columns formwork.
Two methods of stripping CVC Columns’ forms are commonly used.
Unwinding: Use a strong knife and pliers to break the spiral lock at the top of the column
form and unwind it, pulling the plastic profile away from the concrete
column. Once started, the unwinding process can be continued by hand.
Slab Stripping: Using an angle grinder or similar, the column form may be cut from top to
bottom and sprung free from the column.
This method is typically quicker than unwinding, but may leave some marks
on the finished column.
The above information aims to give general guidance to experienced form workers in the use of CVC Columns’ formwork.
It should be read in conjunction with relevant Standards, Specifications and Codes of Practice.