DELTA PT - Cavity Drain Membrane System (Type C)

A dimpled membrane with a mesh face, providing a key for plaster, render or dab fixed plasterboard.

Features and benefits:

• A high performance polyethylene membrane for use on damp and/ or contaminated walls, above and below ground, vaults and basements.
• Delta-PT is extruded into a series of studs to create a continuous air gap behind the waterproof membrane.
• Plastering: The membrane should be plastered with either 'Whitewall' plaster or Carlite Bonding.
• External rendering:
• Where the membrane is to be used externally it must be rendered with a cement-lime-sand (1:1:6) render applied in three coats to a total thickness of 20 mm.
• Due to the difference in thermal characteristics between Delta-PT and the render, expansion joints through the render to the membrane must be trowelled in along each lap joint to reduce the possibility of cracking. These joints must be filled with a suitable flexible polymer-based sealant.
• Alternatively, a polymer/fibre modified render can be used and should be applied in two coats. This render is polymer/ fibre modified, and eliminates the need for extensive expansion joints, other than what is required to meet the Building Regulations.
• A 5 mm ventilation gap at the top, and at least 10 mm at the bottom should be left to assist the ventilation of the air-gap behind the Delta-PT membrane. Delta-PT profile is secured to the membrane and substrate to maintain these gaps.
• Dry lining:
• A Bonding plaster to BS 1191-2, Type A3, is applied in vertical strips over the fixing centres and in bands along the top and bottom of the membrane. The plaster dabs are applied to a minimum thickness of 8 mm, and should cover a minimum of 50% of the membrane.
• Gypsum plasterboard to BS 1230-1,or similar drylining boards covered by Agrément Certificate, are pressed onto the plaster dabs and jointed in the usual manner.
• Decoration: Once the plastered, dry-lined or rendered surface has dried, the surface can be painted or wallpapered using traditional methods and materials.