The first construction step, i.e. digging a hole for the future pond is usually done by the proprietor himself. In this way he can determine the shape, depth and size of the pond. Similarly, laying the outlet pipe and embedding the base in concrete with setting the gully trap is done by means of self-help after agreement with the professional firm. The following step - to cover pond bottom and slopes with a layer of fine sand should be already checked by the firm providing further works. The firm will lay one or several layers of geotextiles, according to the type of background (stony, clay, gravel). Foil (e.g. Aquafol 1 mm thick, produced by Fatra Napajedla) is then laid on the geotextile. The foil can be welded when necessary. Both the foil and geotextile are cut through around the gully trap embedded in concrete. It is fit with a collar which, after drawing up to the gully trap prevents water leaking. The foil around the pond would look unnaturally and thus it should be camouflaged, e.g. with stones or plants. The foil lifetime warranty is at least 15 years.