Izonil Waterproof and Breathable Plaster










Izonil Waterproof & Breathable Plaster provides a completely waterproof barrier, sealing and preventing the ingress of water on either side of the plaster while remaining air-permeable.

Izonil Waterproof & Breathable Plaster offers a unique, long-lasting solution to moisture and vapor related problems associated with a wall’s surface. It is exceptionally applicable in any area of the building industry where waterproofing is essential.

Izonil Waterproof & Breathable Plaster does not contain harmful or flammable ingredients and is environmentally friendly.


Izonil Waterproof & Breathable Plaster is a factory-prepared mixture of Type I or II Portland cement complying with UBC (1997 Uniform Building Code ™) 21.403, sand complying with ASTM C 144, fibers and proprietary additives. Manufactured to strictly controlled specifications, it is supplied as a ready-mixed plaster that requires only the addition of water on site.

Izonil Waterproof and Breathable Plaster is a waterproof, vapor and air permeable, plaster which is installed in accordance with ASTM C 926 over properly prepared concrete, masonry or over framed construction. It is a fine grade plaster applicable as undercoat and professional finish coat.

Depth of water penetration of hardened mortar:    ≤ 1 mm (< 1/25 inch)
Water vapor diffusion resistance coefficient (μ):     12.4
Approx. Coverage:     40 lbs (18 kg) / 1.1 yd2 (1 m2) / 3/5 inch (15 mm)
Minimum thickness:     3/5 inch (15 mm)

• Exceptional waterproofing capability
• Resistant to direct water contact
• Exceptional air and vapor permeability
• Applicable as above-grade or sub-grade insulation
• Excellent cohesion and bonding strength
• Frost resistant and sulfate-proof
• Can be applied to wet surfaces
• Prevents salt efflorescence
• Provides a barrier against wind driven rain
• Can be applied by spray applicator or by hand (trowel)
Possible Applications

Izonil Waterproof & Breathable Plaster is designed for renovating and waterproofing walls of buildings, cellars and basements. It provides a long lasting solution to problems caused by water and moisture in conventional masonry, concrete construction and framed construction. Applications include restoration, repair work and new plastering where protection is needed against water damage.

• Permanent interior and exterior renovation of soaked, wet, salt-damaged
   walls of traditionally-built buildings
• Waterproofing and plaster walls of new and old buildings against floods,
   ground water, fog and other water related elements
• Waterproof plastering of walls of bathrooms, showers, sanitary blocks,
   swimming pools and other wet premises
• Sub-grade waterproofing of footings, cellars, basements, and foundations
• Plastering of light-framed structures
• Permanent interior or exterior renovation of footings
• Waterproof plastering of pits, sanitary equipment/mechanical unit shafts, and    reservoirs

Job Procedures
Surface Preparation

Before applying Izonil Waterproof & Breathable Plaster, it is important to always remove all existing plaster, stucco, loose particles, residual paint, oil, rust, dust and other impurities. Defective wall elements, such as damaged bricks, should be repaired or replaced. If used as a repair mortar, the old plaster should be removed 30-40 inches (800-1000 mm) above the boundary of water incursion. If salt efflorescence is present, jointing must be raked to a depth of 4/5” (20 mm). The wall surface should be thoroughly cleaned with suitable equipment such as high pressure air, water or wire brush. Water absorbent surfaces should be well moistened with water before application.

To maximize cohesion, a thin mixture of cement and water should be spattered onto the surface before plastering.

Once correctly mixed, Izonil Waterproof & Breathable Plaster can be applied direct on damp or wet masonry. In cases of water leaking onto the plastered surface, it is important to ensure that the leakage is stopped for at least 72 hours or more, if possible, to ensure the proper setting of the plaster. Wood or metal laths used on the wall should be secured properly to prevent sagging of lathwork after the plaster is applied.


Add 1.0 to 1.3 gallons (4 to 5 liters) of water to each bag of Izonil Waterproof & Breathable Plaster. Mix for at least for 3 to 5 minutes until the mixture becomes smooth and buttery. Mixing can be performed by hand or by machine. Do not add anything else to the mix.

Izonil Waterproof & Breathable Plaster has a working time of approximately 1 to 3 hours, depending on ambient conditions.


Izonil Waterproof & Breathable Plaster can be applied by trowel or spray applicator. Depending on the conditions of the surface, it may be applied in no more than three layers. Izonil Waterproof & Breathable Plaster is ideal for a scratch and brown base coat, each approximately 3/8” (10 mm) thick. Surface of the first or scratch coat should be cross-raked or scratched, to form a mechanical key for succeeding second or brown coat. Brown coat should be evened to provide a total scratch and brown thickness of 3/4 inch (19mm) if specified. The final 1/12” to 1/10” (2 to 3 mm) of the application can be skimmed. Izonil Waterproof & Breathable Plaster must be cured for approximately eight hours between layers. If the first layer is fully set, it should be moistened before a second coating is applied as it works best wet-on-wet to optimize cohesion. Application shall be in compliance with requirements of applicable codes, regulations and agencies having jurisdiction.

If used as a sealant (e.g. in basements) and applied in different phases, lap joints must be covered completely within the layers to at least 6 inches (150 mm) thickness. However, if only one layer is to be applied, its thickness must be 3/5 inch (15 mm) and should be applied in one run.

Izonil Waterproof and Breathable Plaster is a fine-grained plaster that can be applied as a finish coat. Surface textures as well as finish can be achieved using standard stucco tools, while the plaster is still workable. Hardened plaster should not be remixed or reused!

Post Application Treatment

It is important to prevent Izonil Waterproof & Breathable Plaster from drying too quickly. Sufficient moisture is required to permit continuous hydration of the cementitious materials and to minimize cracking. Moist curing must be provided for at least 24 hours depending on local climate and working conditions. Walls exposed to direct sunlight and wind should be fog sprayed for (7) seven days after plastering. During this process care must be taken to avoid erosion damage to plaster surface. Plastered interior walls require adequate ventilation to cure.

The final layer of plaster may be painted. Do not use oil-based paint. Final layer can be tiled.

When plastering extremely wet masonry with Izonil Waterproof & Breathable Plaster, there is a possibility of water aggregation on plaster surface. This is natural and will disappear as the plaster sets. It may be necessary to remove any accumulated water from the surrounding area.
Use water to remove Izonil Waterproof & Breathable Plaster from tools and equipment. Hardened material can only be removed mechanically.
Izonil Waterproof & Breathable Plaster is supplied in 50 lbs. paper bags.
Approximately 40 lbs (18 kg) of dry plaster will cover 1 m2 (1.2yd2) at 3/5” (15 mm) thick, excluding allowances for waste, surface profile and porosity. One 50lbs (22.7 kg) bag will cover up to 1.4 yd2 (1.2 m2) with a 3/5” (15 mm) thick layer.
Izonil Waterproof & Breathable Plaster will remain usable for up to 18 months if stored in its original packaging on wooden pallets or shelving in dry conditions.