Damage

Repair of damaged areas. For small areas use a short length of Zemdrain® tape. For larger areas place a new piece of Zemdrain® over the damaged area and cut through both layers to form an infill section. Remove the damaged liner and replace with the new piece using staples or tape

Tie Bars

Holes for formwork ties should only be formed after Zemdrain® has been completely fixed to the formwork. Cut a clean hole with a blade cutter and for extra security staple in place.

Release agents

Release agents should not be used with Zemdrain®. They can block the liner pores or cause uneven swelling making the liner unfit for use. Care should be taken to avoid spillage of diesel, hydraulic oil and other contamination onto the liner

Complicated Shapes

Zemdrain® MD is best for complicated shapes. The liner has been successfully used with circular, convex and concave forms.

Joints

For classic, the two pieces of liner are simply overlapped and stapled down.

For MD, the two pieces are butt jointed and  both are stapled down. For good joints no further actions is required. For poor joints the gap should be filled with a sealant or covered with Zemdrain® tape

Spacers

In order to reduce visible imprints on the concrete, such as those caused by spacers, the maximum pressure on Zemdrain® should be less than 20 k/cm². Loading caused by reinforcement should be distributed onto as many spacers as possible

Drainage Path

For Classic, it is essential that he bottom of the liner is open to the atmosphere to permit unimpeded drainage.

For MD, there is usually sufficient storage capacity within the net to accommodate all water removed from the concrete

Steel Faced formwork

Zemdrain® Classic and MD can be used with steel faced formwork. Special fixing techniques may be required depending upon the dimensions of the formwork.

It is essential when using Zemdrain® with steel faced forms to design in the liner fixing details at the time of manufacture of the form.

Panel Systems

Zemdrain® MD & Zemdrain® Classic have been used successfully with large panel systems without the need for over sheeting with additional plywood. Care needs to be taken to ensure that before fitting Zemdrain® that the panels are lying flat and that there are no gaps between them.The resulting surface is not completely flat but is acceptable for most non-visual applications

Concrete Colour

The colour of the finished concrete is primarily a function of the type of cement used. Hence for white cement the concrete colour remains white. For GGBS the colour will be light grey, with other cements giving a darker colour.

The fine aggregate will also have some influence on the colour, as will the amount and uniformity of vibration and curing.