DELTA® TERRAXX in drivable roof decks

DELTA® TERRAXX in drivable roof decks

Delta Membrane Systems Ltd Third party certifications:
  • QA Certificate

    QA Certificate

    Certificate type

A high-density polyethylene dimpled sheet which acts as a surface drainage layer in vertical and horizontal applications.

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A high-density polyethylene dimpled sheet which acts as a surface drainage layer in vertical and horizontal applications.


  • Comprises a layer of polypropylene compression-resistant permanent filtration geotextile, laminated to a silver polyethylene (HDPE) drainage sheet with 9 mm height dimples.
  • The vertical drainage system combines high compressive strength with excellent drainage properties.
  • The integrated geotextile mat filters out suspended soil particles and ensures constant water drain-off through the air gap created by the dimple texturing.
  • The silver surface gives the sheet low emissivity as well as enhancing its heat transition resistance.
  • When applied to perimeter insulation boards, the dimpled sheet provides the necessary insulation from contact with the surrounding soil thanks to its plane reverse face.
  • Suitable for vertical gas (methane and Radon) drainage when combined with a classical filtration gravel layer underneath the floor slab. The top apertures of the drainage sheet should be covered with a layer of gravel to enable the gas to escape into the ambient air without difficulty.

General information

Uniclass 2015

Pr_25_57_65_60 Plastics sheetsPrimary


J40/295 Geocomposite studded cavity drainage/ venting membrane

J42/385 Filter layer

Q37/350 Drainage layer

R16/360 Polyethylene sheet for filter drain capping

Specification data - Plastics sheets

Product Reference



Delta®-Geo-Drain Clip

Attachment clip for fastening Delta®-MS-Profile.

Delta®-Stop Pin

Adhesive pin to facilitate the installation of the dimpled sheet.

Delta®-MS Plug

Nylon percussion plug for concrete or masonry.

Delta®-MS Knopf

Washer fastening.


Brown moulding cap to protect the upper edge of the sheet.


Moulding cap for application to insulation boards (60–100 mm).

Delta®-Terraxx-Schraube fixing

For fastening to perimeter insulation boards.

Standard product features

Technical data:

  • Conforms to CE requirements and those of BS EN 13252, Certificate No. 0799-CPD-13.
  • Drainage rate: Approximately 3.5 L/s per metre.
  • Compressive strength (transient loading): Approximately 400 kN/m².
  • Compressive strength (permanent loading): Approximately 90 kN/m².
  • Installation depth (maximum): 10 m.
  • Service temperature range: -30°C to +80°C.
  • Delta® dimpled sheets are rot-proof, resisting saline solutions, inorganic acids, alkalines, and polar liquids.
  • They are proof against attack or modification by any of the minerals, humic acids, and bacterial catabolic products that naturally occur in the soil, as well as by bacteria, fungi, and micro-organisms.
  • The response of all sheet types to soil or underground water is completely neutral, nor will they leach any harmful and/ or ecologically doubtful substances.
  • Care should be taken to ensure that they are not permanently exposed to UV radiation.

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Third party certifications
  • CE: Conforms to CE requirements and those of BS EN 13252 - Certificate No. 0799-CPD-13
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