Oldroyd Gtx/ Gtx10/ Gtx20


The Oldroyd Gtx range consists of studded polypropylene cavity drainage membranes with a geotextile mesh welded to one side (often referred to as 'geocomposite membranes' or 'geocomposites'). The non-woven geotextile layer is welded to the membranes ensuring that it will not easily separate and won't be subject to slippage during use. The geotextile mesh filters out the 'fines' in the groundwater, preventing them from causing blockages in other areas of the drainage system.

To be applied by a suitably qualified contractor.

Vertical applications:

  • Waterproofing membrane: The Oldroyd Gtx range of membranes is often used when waterproofing earth-retaining structures such as basements and retaining walls. In these situations they are applied externally and are therefore generally used only on newbuild projects.
  • Protection layer: Oldroyd Gtx membranes are usually used as a secondary drainage layer to protect a primary waterproofing system. When used in this way, Oldroyd Gtx membranes are effectively used to replace protection boards, but with the added advantage of diverting the majority of groundwater away from the primary waterproofing system – avoiding the need for drainage aggregates and allowing excavated soil to be reused as backfill.
  • Fin Drain: Oldroyd Gtx membranes can also be used as ground pressure relief fin drains in civil engineering applications and as vertical edge drains around pavements and carriageways.

Horizontal applications:

The Oldroyd Gtx range of membranes can be used as horizontal drainage layers in a wide range of applications including:

  • Green roofs.
  • Roof decks / terraces.
  • Reservoir roofs
  • Podium decks.
  • Balconies.

Joint laps:

  • Vertical joint: minimum 200 mm overlap is recommended; sealed with sealing rope.
  • Horizontal joint: minimum 150 mm overlap is recommended; sealed with sealing rope.

General information

Uniclass 2015

Pr_25_57_65_60 Plastics sheetsPrimary


J30/330 Protection of external coatings

J30/80 Protection of coatings

J40/295 Geocomposite studded cavity drainage/ venting membrane

J40/380 Protection boards for damp proofing/ tanking

J40/70 Protection boards for damp proofing/ tanking

R16/380 Sheet fin drains

Specification data - Plastics sheets

Product Reference

Oldroyd Gtx membrane

5 mm stud.

Oldroyd Gtx10 membrane

10 mm stud.

Oldroyd Gtx20 membrane

20 mm stud.

Joint sealant

Not required

Oldroyd sealing rope

Standard product features




  • Membrane: 0.5 mm.
  • Stud height: 5 mm (Gtx), 10.5 mm (Gtx10) or 20 mm (Gtx20).

Compressive strength:

  • Gtx: > 400 kN/m².
  • Gtx10: > 700 kN/m².
  • Gtx20: > 150 kN/m².