Moisture-resistant plaster

When building or renovating, moisture-resistant plaster is a must, particularly in locations with high humidity levels. Using the appropriate type of plaster can make all the difference when it comes to shielding your walls from moisture and potential damage, whether you’re working on a kitchen, bathroom, or basement.

Because it is specifically designed to resist moisture, this kind of plaster is perfect for conditions where regular plaster would degrade rapidly. It produces a strong, water-repellent surface that keeps your walls looking new for years to come and aids in the prevention of mold growth.

This post will discuss the various varieties of moisture-resistant plaster, how to select the best type for your project, and some useful application advice. Understanding the advantages and correct application of moisture-resistant plaster can ultimately save you time, money, and effort—whether you’re a professional or a do-it-yourself enthusiast.

Feature	Description
Moisture Resistance	Designed to withstand high humidity levels, perfect for bathrooms and kitchens.
Application	Can be applied to walls and ceilings, creating a smooth and durable surface.
Drying Time	Typically dries within 24-48 hours, depending on the thickness and environmental conditions.
Finish	Offers a variety of finishes, from smooth to textured, allowing for customization.
Compatibility	Works well with various types of surfaces, including concrete, brick, and drywall.
Durability	Highly durable, providing long-lasting protection against moisture damage.

Waterproof plaster. What is it

Water-resistant waterproofing plaster is a type of finish designed to be used in high humidity environments.

Polymer hydrophobic additives that are part of mortar mixture composition provide high moisture resistance.

The ability of moisture-resistant plasters to let vapor through and let the walls "breathe" is their primary benefit.

This feature stops the growth of microorganisms and mold on the walls while enabling you to establish a cozy microclimate in the space.

Glass and mirrors in rooms with moisture-resistant decorative finishes don’t fog up.

For wet rooms, decorative plasters serve as finishing plasters; no additional coatings are needed.

A key component of wall protection in moist or humid spaces, like bathrooms, kitchens, and basements, is moisture-resistant plaster. It guarantees a long-lasting finish that is resistant to moisture exposure in addition to assisting in the prevention of water damage and the growth of mold. Because of its unique formula that repels water, this type of plaster is the best option for areas where traditional plaster might not hold up. Homeowners and builders can create resilient, cozy, and safe spaces by being aware of its advantages and applying it properly.

Classification of waterproof plasters

There are two types of water-resistant plasters: leveling and decorative.

Leveling waterproof plaster establishes a stable and long-lasting foundation for additional ceramic tile cladding or moisture-resistant paint applications.

Venetian plaster is frequently used to decorate moist and humid spaces. It is coated in a unique protective wax. In terms of moisture resistance, this finish is on par with tile cladding. The most expensive and difficult-to-apply decorative coating is Venetian plaster.

Recommendations for choosing formulations

The type of coating, base material, application technique, and building owner’s financial resources all influence the choice of waterproof plasters.

If a covering beneath tiles is needed, precise alignment and a strong base are necessary. Cement and mixtures of cement and polymer completely satisfy these requirements.

Waterproof compounds can be painted on Knauf or Ceresit plaster mixtures designed for wet rooms. A thin layer of Aquastop primer will be applied to provide additional moisture protection.

Because protective wax coatings are applied, Venetian has excellent waterproofing qualities, making it the best decorative finish for wet rooms.

Cement mixtures

Cement and sand are combined with plasticizers and hydrophobic modifying additives to create cement mixtures.

Water resistance and great strength characterize cement plasters for wet rooms.

It is preferable to purchase pre-made dry mixtures that come in a variety of forms on the construction market and have perfectly balanced components:

• waterproofing mixture EC, for plastering on stone and brick;
• Ceresit CR 65 – for any base;
• AZOLIT-VSH – for finishing on concrete and brick;
• Profit Gidrofob for applying an additional waterproofing layer to plastered bases;
• Murexin Waterproofing Hydro Basic 1K, suitable for any base;

This solution needs to be made using a construction mixer or a hammer drill attachment with a mixing attachment, following the directions on the package.

Making cement mortar by hand requires taking a 1:3 mixture of cement and sand, adding PVA glue to make it more water resistant, and adding washing powder to make it more ductile.

Gypsum compositions

The most widely used dry mixes of gypsum plaster for wet rooms are Rotband from Knauf and UNIS Teplon.

Gypsum’s high water absorption is a drawback that can be overcome by impregnating the gypsum finish with water-repellent primers and adding PVA glue to the final solution.

Compositions with polymer additives

High levels of strength, plasticity, and water resistance are found in moisture-resistant compositions made with polymer fillers.

The most often used combinations:

• Profit Barrier, ideal for the base under ceramic tiles;
• Dufa Kratzputz aussen hydrophobic water-repellent plaster, on an acrylic base, is suitable as a decorative plaster for wet rooms. It has an original texture similar to an orange peel;
• Dry moisture-resistant mixtures STUC DECO and STUC GRANITO, based on polymers, can be used as a finishing decorative coating.

Technology of working with moisture-resistant plaster

The base must be cleared of dust, debris, old finishing coats, and crumbling layers before any work is done.

For improved coating adhesion to the wall, remove any mortar from the masonry joints down to a depth of 5 to 10 millimeters before plastering the wall.

Use a chisel to make shallow indentations on the surface of plastered walls to level them.

When plastering concrete walls, use a hammer drill fitted with a spatula attachment or a grinder with a diamond wheel to create notches that are at least 3 mm deep.

Apply two coats of primer to the wall. Once the first layer has fully dried, the second layer is applied.

Before beginning work, plaster mixtures for wet rooms must be carefully prepared, adhering to dosage guidelines and preparation instructions.

Application of the solution

Three layers are applied to the wall in the technology of plastering with moisture-resistant compounds: spray, primer, and covering.

The first layer, or splash, is composed of a creamy-consistency solution. Using a trowel, we hurl it in an arbitrary pattern onto the wall. This method of applying the solution fills in all the gaps and voids.

We remove areas of the first layer that protrude and level it slightly.

For walls made of brick and concrete, the splash should not be thicker than five millimeters. For walls made of wood, 10 millimeters.

No sooner than a day after the splash has dried is the second layer, or primer, applied. The primary layer, known as the primer, can have a thickness of up to three centimeters. Using a wide spatula or trowel, we apply the moisture-resistant solution and pull it along the beacons in zigzag patterns, working our way up from the bottom.

The third layer is a covering that is 1.5–2 millimeters thick. It is applied onto a surface that has been pre-wetted after the previous layer has solidified, and it is smoothed over with wave-like motions using a trowel or wide spatula.

We grout in a counterclockwise circular motion using a wooden or plastic float, without waiting for the moisture-resistant finishing layer to dry.

Using a float fitted with felt or fixed felt, the final sanding is completed.

Grouting the plaster is not necessary when tiling later on.

For areas like bathrooms, kitchens, and basements that frequently experience humidity or direct contact with water, moisture-resistant plaster is a necessary solution. Its resistance to moisture aids in preserving the integrity of your walls over time by averting problems like mold development, moisture, and deterioration.

This kind of plaster improves the visual appeal of your interiors in addition to offering protection. You can make sure that your walls stay sturdy and attractive for many years, even in difficult circumstances, by selecting the appropriate moisture-resistant plaster.

For the longevity and well-being of your living spaces, adding moisture-resistant plaster to your building or renovation projects is a prudent financial decision. It’s a dependable choice with both functional and aesthetic advantages, suitable for both professionals and do-it-yourself enthusiasts.

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