The control of rising damp using cream or gel damp course materials.
Recently we have seen the introduction of creams/gels/pastes as a new way of introducing a chemical damp proof course into an existing structure. These are high viscosity materials with a consistency somewhere between mayonnaise and thick wallpaper paste. They are introduced into a wall with virtually no pressure, often using a hand held applicator. Whereas ‘damp course fluids’ are all very similar in type and the amount of active ingredient they contain (there are a few cheap exceptions that have a reduced the level of active ingredient), these new high viscosity materials contain very different amounts of active ingredient. Granted they all look the same and some will therefore inevitably believe that if they look the same then they will perform the same. This may well be the case but as the composition of each varies so much and none as yet has a long term proven track record some form of independent test comparison is required in order to help people make a judgement.

Fluid discrepancies now removed
A very interesting point concerning the use of these high viscosity materials is that they remove virtually all of the possible discrepancies historically associated with the introduction of ‘damp course fluids’. The manufacturers of the new high viscosity creams/gels/pastes stipulate the drill hole size, depth and centres into which the material is to be introduced. Furthermore as no pressure is involved an exact quantity of material is introduced into each drill hole as directed by the manufacturer. This ‘drill and fill’ one shot introductory process now totally removes the vagaries of insufficient material having been injected or inadequate diffusion having taken place and virtually eliminates operative error.

Manufacturers beware!
If we look to the future and imagine that it becomes necessary to investigate in detail a guarantee claim where one of these high viscosity materials was used. If the definitive test described in BRE Digest 245 when combined with a salt profile has proved continuing active rising damp is still present and it is established that the drill hole size, depths and centres are all correct then there is only one conclusion left. Continuing rising damp would have to be down to product failure. What else could it possibly be? The only imaginable vagary is that the hole may not have been fully filled but it would be relatively simple to prove this one way or another therefore any failure in performance will lay squarely at the manufacturer’s door.

These new one shot ‘drill and fill’ materials have been extremely well received by the industry because of their simplicity. However never before has the ability to pin point product effectiveness been so available to a contractor so manufacturers beware!

© Property Guarantee Administration 2004 Macdonald

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