Product Description
Rendermix is a concrete integral liquid waterproofer incorporating a fungicidal additive and inhibitor for use in rendering after a chemical DPC has been installed. It may also be used in mortar and concrete mixes.
Rendermix will prevent hygroscopic salt movement causing secondary dampness in rendering after a chemical injection or DPC installation.
Rendermix
is an alkaline soap of mixed fatty acids compounded to a soft easily
dispersed solution. Rendermix is initially alkaline, and has no
corrosive effect on reinforcement. It is economical and convenient to
use. Not only is water repelling to reduce penetration but also water
retentive which aids curing, ensuring maximum strength. It will help
reduce the formation of efflorescence and lime bloom by restricting
moisture movement and aid the reduction of crazing in rich mixtures by
controlling rate of water evaporation.
Rendermix may be used in
any situation where it is necessary to construct cement based sections
resistant to external water pressure, or to contain water in an
enclosure.
Structures containing Rendermix are not vapour-proof
and therefore where applicable (i.e. flooring) a suitable vapour-proof
membrane should be included
Application
Where specific building methods are covered by British Standard Code of Practice, these should be followed as a guide to good building Practice. New brickwork to be rendered should be left with raked mortar joints to form a key. Old brickwork, concrete or rendering should be raked out or hacked; existing plaster and decoration must be removed completely.
Make good loose areas of rendering and ensure backing is sound, free from dust, laitance, paint, grease, oil surface water or any other contaminants which may affect adhesion.
Porous surfaces must be established, for example with 1 part SBR Bonding Agent mixed with 2 parts cement (by volume) to produce a thin, smooth cream. Brush this mix vigorously into the surface and allow to harden (minimum 16 hours, maximum 3 days), then apply a bonding primer (to a dry surface), composed of 1 part SBR Bonding Agent, 1 part water mixed with 5 parts cement (by volume). Render/screed into the bonding primer whilst still wet / external renderings, mix designs should be chosen to suit the background, the exposure and the type of finish required.
The mix design for each successive coat should be weaker and thinner than the coat to which it is applied.
MIX A: Waterproofing structures against ground water pressure, water retaining structures (swimming pools, tanks and ponds) and re-plastering after insertion of a DPC:
Cement: 1 part by volume
Sand: 21/2 parts volume
Rendermix/water: 1:25
Approximate yield per 50kg of cement = 0.14m3.
MIX B: Screeds (minimum thickness 50mm)
Cement: 1 part by volume
Sand: 1 part by volume
10 - 12mm granite or shingle aggregate: 2 parts by volume.
Rendermix/water: 1:30 (Gauge to a working consistency). The sand should conform to BS 882: 1992 Type M (flooring sand).
Approximate yield per 50kg of cement = 0.16m3.
Product Data Sheets
Technical Data Sheet Safety Data Sheet
