Protecto-drain 8 is a dimpled HPDE membrane, sometimes called a cavity drain, for use against foundation walls, basements and subterranean concrete, waterproofed structures. It is designed to protect the structure against mechanical damage and to create an air gap between the waterproofing and the earth, producing a reliable drainage channel for groundwater to pass down the surface of the structure and into a suitable sump or channel. The membrane means that hydrostatic pressure does not develop within the structural layers, avoiding the risk of punctures and damp building up.

They are lightweight and easy to install and fix. Installation is quick and very cost-effective.

Applications include:

• Retaining walls
• Walls built half exposed/half buried 
• Abutment drainage
• Gas dispersal & collection
• Erosion control
• Sports field drainage
• Road construction
• Basement waterproofing

Installation

Protecto-drain 8 Place the dimpled sheet against the foundation wall or structure and overlap each sheet by at least 20cm. The cups should face the structure on their underside, so that the open cup is facing the ground / earth / backfill.  For bonding each sheet together, install double-sided PROTECTO-TAPE along the full length of one sheet and remove the slip foil.

Place one sheet on top of the other by pressing the open cups into those on the other sheet - the cups will fit neatly within the angled sides into the cup/button. The PROTECTO-TAPE is designed to hold the sheets in place temporarily before the backfill process takes place. Sheets can also be secured using clout nails and buttons (available from Wallbarn), clamped down with a batten fixed at the top of the membrane or fixed with a bolt gun.

Fill the void behind the membrane with free-draining aggregate such as gravel or loose stones. The dimpled membrane should always be installed so that the top of it protrudes above the level of the backfill.