Penetrative Damp Treatment

Storm dry is a colourless, breathable, water-repellent treatment for brick, concrete and stone walls. It is supplied in the form of a deeply penetrating cream that is applied to the wall surface using a roller or brush. Once Storm dry has been applied to the wall surface, it will permeate deeply before curing to form a water-repellent barrier. Typical applications for Storm dry include:

  • Protecting against penetrating damp (rain penetration)
  • Improving the thermal resistance of masonry by keeping it dry (energy saving)
  • Improving the performance of cavity wall insulation by protecting it from moisture
  • Improving flood resistance of masonry

Breathable and Long Lasting

Storm dry is based on carefully selected silanes and siloxanes which line the pores of the masonry to form a water-repellent silicone matrix. Because it works by lining the pores rather than blocking them the masonry is allowed to breathe and does not suffer from increased frost damage (spalling). Due to its novel formulation and deep penetration, Storm dry is resistant to UV light and other forms of degradation, resulting in a life expectancy of 20-30 years.

Deeply Penetrating

Storm dry is able to penetrate more deeply into masonry than traditional liquid-applied masonry water repellents. As well as increasing life expectancy this also improves Storm dry’s crack-bridging ability. As the diagram below shows, Storm dry is able to provide water-repellency beyond the depth of small cracks:

It should be noted that larger cracks will still need to be filled as part of the Storm dry treatment. Mortar lines may need to be repointed with a sand/cement or sand/lime mix incorporating Storm dry Repointing Additive.


Storm dry has been tested to EN ISO 15148:2002 (E), demonstrating its effectiveness on concrete, mortar, brick, and sandstone. The graph below shows that the water uptake for Storm dry treated samples was considerably lower than for untreated samples:

As Storm dry is formulated to penetrate deeply into masonry it can take up to two months after application for a noticeable “beading effect” to appear when rainfall strikes the wall. However, Storm dry is resistant to rain after just 12 hours. This can be confirmed by using a Storm dry Gauge (pictured below).

In common with most other masonry water repellents, Storm dry’s beading effect will become less pronounced after two or three years. However Storm dry will continue working for 20-30 years. Once again this can be confirmed by using a Storm dry Gauge.

Improving the Thermal Performance of Masonry

Improving the thermal resistance of walls through the use of conventional insulation is not always practical – particularly where older buildings are concerned. Many homes and commercial properties in the UK are built using single-skin walls, making them unsuitable for cavity wall insulation. The installation of internal insulation can be disruptive and takes up valuable living space whilst externally applied insulation is often unattractive.

Fortunately, Storm dry offers a solution. It is a well-known fact that porous masonry materials such as brick, stone, concrete, and mortar are worse insulators when they are wet. By preventing the absorption of water, Storm dry ensures that the insulation properties of the masonry are maximised throughout the year.

Tests carried out using Storm dry at the University of Portsmouth and subsequent SAP analysis showed that energy savings of up to 27% are possible when Storm dry is used on single-skin walls due to reductions in thermal conductivity. This has been verified in an independent report carried out by environmental consultants, Giraffe Innovation. When the effects of reduction in evaporative cooling are taken into account, total energy savings of up to 29% are possible.

Improving the Flood Resistance of Masonry

Storm dry can be used to increase the flood resistance of masonry as part of a flood resistance or resilience system. It is particularly effective when used in conjunction with repointing up to design flood height using a mortar incorporating Storm dry Repointing Additive No.2.

When used as part of a cavity drain flood protection system (e.g. Oldroyd Xv), Storm dry will increase the primary resistance of the masonry – reducing the risk of ingressing flood water overwhelming the pumping system. Contact our technical department for details.