waterproofing membranes, damp proofing, Delta PT

FINISHING WORKS

PLASTERING
Delta-PT should be plastered with either:
• ‘Whitewall’ plaster
• Carlite Bonding.
A 6mm scratch coat must be applied and allowed to set before
applying the next coat, in accordance with in BS 8481: 2006, BS EN
13914-2 : 2005 (and / or the appropriate Agrément Certificate).
The standard of installation should comply with the requirements of
BS 8000-10 : 1995. The plaster should be a minimum total depth of 15 mm.

Where a sand-cement mix is to be used internally, two coats are
applied and finished with a 3 mm thick gypsum-based skim coat.
A further plaster option is Roundtower Natural Hydraullic Lime Plaster
- seek advice from Delta.

RENDERING EXTERNALLY
Where Delta-PT has been 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 using the procedures defined in BS EN 13914 -1 :
2005. The standard of installation should comply with the
requirements of BS 8000-10 : 1995.
The render should be applied in three coats with seven to ten days
being allowed between coats.
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 polymerbased sealant.

Alternatively, polymer modified render should be applied in two
coats. The render is polymer/fibre modified, and eliminates the need
for extensive expansion joints, other than what is required to meet 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 EN 13279-1: 2005, is mixed and 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 EN 520: 2004, or similar dry lining boards
covered by Agrément Certificate, are pressed onto the plaster dabs and
jointed in the usual manner. Temporary spacers approximately 20
mm to 25 mm high are positioned under the dry lining to support it during the curing period.
DECORATION
Once the plastered, dry-lined or rendered surface has dried, the
surface can be painted or wallpapered using traditional methods and materials.