Homes throughout the UK may be at risk from rising
damp despite being equipped with chemical damp-proof courses (DPCs), according
to research from Safeguard Europe – the UK’s leading
specialist in damp-proofing and waterproofing technology.
Laboratory
tests at its research and development laboratory have proven that DPC creams
with low concentrations of silicone will ultimately prove ineffective.
DPC creams
work because they contain silicone that penetrates the pores of the mortar in
masonry and brickwork to form a waterproof seal. Some DPC creams on the market
contain as little as 10% silicone.
Yet UK
testing and certification takes no account of the silicone content of these
creams and their consequent performance.
Only
comparative testing on a range of products will demonstrate these differences,
so Safeguard pitted its own high-silicone content products, Dryzone
Damp-Proofing Cream and Dryzone Damp-Proofing Rods, against two DPC creams that
contained 20% and less than 15% silicone respectively. All four products are
certified by a leading UK test house.
The
experiment consisted of preparing five pieces of lime mortar, each with a hole
in the centre. They were left for four weeks and then each was injected with
one of the DPC treatments, with one piece left untreated as a control for
comparison.
They were
left to cure for a further four weeks and then split in two to reveal the
extent of the waterproof zone. The results were in line with earlier research
by the University of Portsmouth, showing that the size of the waterproof zone
around the injection holes is relative to the amount and strength of active
material injected.
The low
strength creams do not create a waterproof zone as large as that produced by
high-strength products such as Dryzone Damp-Proofing Cream or Dryrod
Damp-Proofing Rods, which diffuses silicone throughout the pores of the mortar
when inserted into drill holes.
This means
that the low strength creams are more likely to fail because the further the
spread the more effective the treatment. If the creams do not spread far enough
then they will still allow moisture to rise in those areas they do not reach.
