(photo: Belzona International)
13.02.2017, 23:43

Preventing Dampness with an Invisible Wall Treatment

External walls are frequently exposed to rain which enters porous masonry surfaces and penetrates internal walls unless they are protected.

External walls are frequently exposed to rain which enters porous masonry surfaces and penetrates internal walls. A common cause of mould growth, dampness will deteriorate walls quickly and even poses potential health risks.

In stone buildings which predate the introduction of cavity walls, the problem of damp is common. In the winter months, external walls can also be affected by freeze-thaw cycles, where water penetrates the masonry and freezes, creating cracks and eventual erosion. Evidently, to protect these walls from external and internal degradation, they need to be shielded from water penetration whilst simultaneously letting internal moisture escape (a characteristic that is often referred to as "breathability").


Some commonly used waterproofing materials permanently seal the external wall, trapping existing moisture within, making the wall susceptible to cracking during freeze-thaw cycles. An alternative to sealing would be to impregnate the substrate with a clear waterproofing treatment. This method lets the treatment penetrate deep into the building fabric, allowing any moisture to evaporate, while keeping the water out. The difference between sealing and impregnating can be seen in the diagram below. An additional benefit of a clear treatment is its absence of colour, so the appearance of a treated building can remain as it was intended.


A range of waterproofing treatments is currently available on the market with varying expected lengths of service, including our own Belzona 5122 "Clear Cladding" product which forms an invisible, micro-porous, water repellent barrier that allows the passage of air and water vapour, ensuring that moisture is not trapped in the substrate. This single component material is supplied as a concentrate for dilution with water prior to use and can be brush- or spray- applied.

In addition to waterproofing buildings, Clear Cladding reduces dirt retention. This water repellent treatment for masonry protection can be applied onto concrete, limestone, brick, sandstone and other natural materials, and dries within 2 hours under normal climatic conditions.


Em Robinson from Anglesey, North Wales, commented on her experience with Clear Cladding: “We first used this product 19 years ago and have only needed to reapply after some ingress of water last winter, which was an exceptionally bad one. We are especially pleased with the finish as it is invisible, not altering the look of the stone or mortar in any way. The only noticeable difference is, when raining, the stone remains its dry colour and you can see the water 'beading’ off the surface. The other advantage of this product, as opposed to other waterproofing methods, is that you can see when it is no longer working by splashing water onto it and only have to reapply the areas no longer repelling water. Also you only need one application.”

The treatment has been used to protect commercial, industrial and private buildings and structures against dampness whilst reducing the effects of erosion and efflorescence.



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