Clay is the original waterproofing material and, if used correctly, offers the best long term solution to waterproofing larger lakes and reservoirs. Clay is the best option if the material can be found on site. It can be expensive and less environmentally friendly to import clay onto site for use as a waterproof membrane. If you are considering a pond, lake or reservoir and you believe there is a chance clay is available on site, telephone and speak to Chris Keech on 01460 279 200 to discuss your options.