Utilizing today's modern construction techniques, developers and engineers are able to realize the full potential of land both above and below ground. Parking garages, subways, shops and storage areas are commonly situated underground without restriction or hinderance from what lies above. Lead waterproofing is often specified when installation or construction occurs beneath landscape plots, reflecting pools, fountains or planter boxes. Lead membranes or pans, when installed correctly, provide an impermeable moisture barrier that will last as long as the buildings that surrounds them. Waterproofing today means "membrane", which includes built up or laminated coverings made up of large unbroken surfaces demanding continuous integrity of the barrier for water-tightness. Most installations of this nature use lead "burning" (welding) to join the sheets as large as needed and that can be handled. In waterproofing situations where increased safety is a factor or greater long-term reliability is desired, lead should be specified at 6 lb. or 8 lb. per square foot weight or equivalent to 3/32? or 1/8? thickness. However for less demanding or critical areas such as shower stalls, a lighter sheet lead weight of 4 lb. or 1/16? is used.