It is acknowledged that when renovating old buildings, basements, cellars, etc a major challenge is solving the problem of damp and wet walls.

Buildings lose their resistance to water over time and this promotes the capillary action of rising damp. Dampness penetrates through the walls into the plaster and causes wet patches, the formation of mildew and salt efflorescence – all of which can cause the plaster to fall off.

Such problems make a house uncomfortable and unhealthy to live in. Ultimately parts of the property will become uninhabitable.

Conventional waterproofing methods require several processes. For example, one of the most well known techniques is to apply a membrane between the walls and the plaster. Multi-step processes are both time consuming and costly.


The one step waterproofing solution developed by Izonil simplifies the whole process. It’s Waterproof and Breathable Plaster provides a totally waterproof barrier, without the need for a membrane. Applied direct to walls it seals and prevents the ingress of water either side of the plaster while remaining vapour and air-permeable, allowing trapped moisture to evaporate. Unlike most waterproofing solutions, Izonil Waterproof and Breathable Plaster does not trap moisture by “wrapping the wall in a plastic bag.”

How to use?



Before applying Izonil Waterproof and Breathable Plaster mechanically prepare the substrate to provide a structurally sound surface. Remove all existing render, plaster, grease, oil, dirt and deleterius material. Clean the surface with clean water. To maximize cohesion a thin mixture of cement and water slurry or other standard primer must be applied on to the surface before plastering.




Add 4.5 to 5 liters of clean water to each bag (25kg) of Izonil W&B Plaster. Mixing is recommended by hand or concrete mixer, forced action mixer. Mix for at least for 3 to 5 minutes in the mixer until the mixture becomes smooth, thick, creamy consistency.





Izonil W&B Plaster can be applied by trowel or mortar gun. Apply in one single layer, 15mm thick or in 2-3 layers, 10mm thick per layer. Izonil W&B Plaster is a fine grade mortar and so offers a 'one coat' solution providing undercoat and professional finish coat. Can be finished with standard plastering tools, while the product is still workable.



Customer feedback

"As in every job the final outcome generally rests with the degree of preparation that has gone before it, as we were working on an old brick vault. We blasted the walls as recommended with a high pressure water hose, which was both quick and effective. From then on it was a case of "Izonil W&BP" does everything it says on the tin. If you are working in a confined space like we were clear the area completely and put a cover on the floor, this is more for the pre-application coat of cement and water than the Izonil. The Izonil is easy to prepare and apply leaving a much better finish than I had anticipated. We applied it as one 15mm coat, which seems perfectly adequate. For some reason from mixing onwards the product inspired me with the confidence it was going to work, and it has brilliantly, we got about 1.5m2 per 25kilo bag, which to my mind makes it a very cost effect remedy to the perennial damp problem. What I really like about the spec is that it is breathable, so I am much looking forward to using it for the first time in a external application, traditional render making some stone built buildings sweat internally. Thank you for introducing this product to me, I consider its place in my product awareness, another string to my bow in my efforts to become a building sage."

Builder N.H.B.C


Before using our product, please read through our Technical Data Sheet.