Calder lead


We recommend the installation of underlay to isolate the lead sheet from its substrate. Its usage allows effective expansion and contraction between the two layers (due to temperature changes), by reducing drag.


Building Paper has a wide range of uses within the construction industry including use as an underlay for lead sheet, providing a separation layer between materials and as a form of temporary protection.

It is suitable for use on smooth substrates including plywood (providing its underside is ventilated) and natural stone surfaces.

When used on smooth concrete or screed finishes the building paper forms a protective layer which prevents chemicals, such as alkalis in cement, penetrating and damaging the lead sheeting.

Calder’s building papers all conform to British Standard BS1521 Class A.

Available in:

  • Standard Building Paper - 25 m x 1000 mm rolls
  • Moisture Resistant Building Paper - 25 m x 1000 mm rolls


Calder’s geotec 220PY underlay is only suited for use on existing traditional timber board substrates in conjunction with ventilation. It has been specifically designed and manufactured to prevent ridges and fractures forming in each lead sheet, where thermal movement causes it to pass over the edges of individual boards.

Extremely lightweight (weighing only 220 g/m2), it is a high-quality, durable, non-woven, needle punched, polyester textile underlay.

Available in:

  • 25 m x 1000 mm roll
  • 50 m x 1000 mm roll