Cordek offers a range of formwork solutions for the construction of in-situ ground beams & pile caps. The Sideform system is manufactured from twin wall polypropylene sheet which can be supplied pre-formed to customers dimensions or in standard sheets for fabrication on site. Sideform is a permanent formwork solution for the construction of in-situ ground beams & pile caps. Sideform is manufactured from twin wall polypropylene sheet which can be supplied pre-formed to customers dimensions or in standard sheets for fabrication on site.