4. WYKAMOL INTEGRAL WATERPROOFING LIQUID

DESCRIPTION: Wykamol Integral Waterproofing Liquid (IWL) is an additive designed for use in sand/cement mixes following the insertion of a chemical d.p.c. and other waterproofing situations. Based on an alkaline soap of mixed fatty acids, Wykamol IWL performs by forming hydrophobic salts with cement thereby reducing permeability. This product is manufactured under a quality system complying with BS EN ISO 9001:1994.

SITE WORK
Application: Wykamol IWL should be used in a 3:1 sand/cement mix at the dosage rates noted on the product label, and added to the gauging water before mixing. The constituents of mixes should conform to the following descriptions:

a) Ordinary Portland Cement (OPC) to BS12: 1991.
b) Aggregate - clean sharp washed sand. The coarsest, sharpest sand graded for plastering is preferred (ideally this should conform with BS1 199:1996 Type 'A').
c) Water - fit for drinking and free from organic matter.

The sand/cement mix should be applied at a thickness of 10 mm. Where a second coat is required this should incorporate the admixture at the same dosage rate and be an equivalent or slightly weaker mix (i.e. 4:1) than
the initial coat. The surface of each coat should be lightly scratched to provide a physical key for subsequent coats.

N.B. Wykamol IWL is not suitable for use in lime-based mixes or mixes with a lower cement content. The following should also be noted and may be relevant to the use of Wykamol Renovating Plaster

a) The amount of gauging water in undercoats should be the minimum consistent with reasonable application.
b) Strong mixes should not be applied over weaker substrates, i.e. old plaster, soft bricks etc.
c) Undercoats should be scrape finished to reduce cracking. In hot and dry conditions rapid water loss during the curing period should be prevented by the use of polythene membranes, fine water sprays etc. This will reduce the risk of shrinkage cracking and ensure correct cement hydration (strength development).
d) New plasterwork should not bridge the d.p.c. and finish 25 mm short of the floor.
e) Gypsum based materials should not be used in direct contact with damp-proofed walls, e.g. lightweight gypsum undercoats, gypsum adhesives etc.
f) No more than two plaster coats (sand/cement 20 mm total thickness, Renovating Plaster up to 30 mm) should be applied in one continuous working process. If greater thicknesses are required the first coats should
be scratched and left to cure (7-14 days) prior to applying an SBR-modified cement slurry and proceeding as above.
g) Where appropriate, external renders should be applied in accordance with BS5262: 1991 and terminate with a bell mouth just above the d.p.c. level. Any external feature likely to lead to ongoing sources of penetrating damp should be rectified; in particular, porous brickwork on exposed elevations may benefit from protection with a masonry water repellent.