Dry Expansion Of Wet Rooms: Stay Dry Despite The Wet

2023 Author: Hannah Pearcy | [email protected]. Last modified: 2023-11-26 11:39

Domestic bathrooms and other wet rooms are increasingly being constructed using dry construction methods. But which plates are the right ones for which applications? When and how do you have to seal? And what should be considered when filling? Dry expansion of damp rooms - what to look out for.

Author: Susanne Sachsenmaier-Wahl

Dry expansion of wet rooms: This is supported in particular by short construction times and efficient processing. Another great advantage is the fact that water and sewage pipes can be easily installed within the constructions without having to laboriously slit open and close the walls. Installation problems, which are often said to be easy drywall construction, can be easily dealt with: Installation walls with appropriate supporting frames also allow the washbasin and wall-hung toilets to be securely attached. Compared to solid constructions, drywall constructions also score points thanks to their better adaptability to structural conditions. And when it comes to the architecturally sophisticated design of sanitary rooms, dry construction is the method of choice anyway. Curved walls, stems, even bathroom furniture can easily be created with the appropriate building materials. And last, but not least, the list of modernization measures currently tops the barrier-free expansion of the bathroom - and this can be implemented quickly and safely, for example, with appropriate dry screed elements.

For every stress

Before a dry expansion in damp rooms can start, the future use and thus the exposure to moisture and moisture must be clarified. This usage-dependent evaluation is crucial for the correct choice of plate types. Leaflet No. 5 of the Federal Association of Gypsum Industry eV Gypsum Board Industry Group divides moisture exposure into classes:

Stress class 0:

Wall, floor and ceiling surfaces that are only occasionally and temporarily exposed to splash water (e.g. guest toilet (without shower and bathing facilities), utility rooms, kitchens with normal household use, walls in the area of sanitary objects, e.g. B. hand basins and wall-hung toilets, ceilings in bathrooms with normal household use)

Stress class A0:

Wall, floor and ceiling surfaces that are only temporarily and temporarily exposed to splash water (e.g. bathrooms with normal household use or hotel bathrooms in the immediate splash water area of showers and bathtubs with shower partition, without and with a floor drain that is used as planned, such as barrier-free showers)

Stress class A:

Wall, floor and ceiling surfaces that are heavily used by service and cleaning water (e.g. walls and floors in public showers, in wet rooms of sports facilities and wellness areas, swimming pool surrounds)

There are also stress classes B and C, which deal with wall and floor surfaces in swimming pools and rooms with chemical stress. These specialist areas should not, however, deal with these areas any further.

Types of plates

The (plaster) board industry has a wide variety of products suitable for use in damp rooms. A selection of these is presented below:

Impregnated gypsum boards and gypsum fibreboards

Impregnated gypsum boards consist of a gypsum core covered with cardboard. This cardboard is easily recognizable by its greenish color. Gypsum fibreboards are homogeneous gypsum-bound drywall boards with paper fibers; they are already hydrophobized at the factory. Impregnated boards have a delayed water absorption and are mainly used in damp rooms in living areas and rooms with similar loads. Product examples for impregnated gypsum boards: "GKBI building board" from Knauf, "RBI building board" from Rigips, "LaGyp impregnated" from Siniat. Product examples for gypsum fiber boards: “Fermacell” board, “Vidiwall” from Knauf, “Rigidur” from Rigips

Fleece-reinforced plasterboard

Fleece-reinforced gypsum boards have a special resistance to moisture and mold. A UV light-resistant glass fleece safely encases the highly hydrophobic gypsum core of the board. Alternatively, the glass fleece can also be embedded on the surface. These panels are perfect for moderate moisture applications. They have been specially developed for use in damp and wet room areas with moderate to high loads. Product examples: “Drystar Board” from Knauf, “Glasroc X” from Rigips, “La Hydro” from Siniat

Cement slabs

Cement-bound, water-resistant drywall boards come for expansion concepts in all areas subject to high humidity, including chemical loads - such as B. swimming pools, rehabilitation, wellness objects or canteen kitchens and laundries - for use. Product examples: "Powerpanel H2O" by Fermacell, "Aquapanel Cement Board" by Knauf, "Aquaroc" by Rigips, "Hydropanel" by Siniat

Cement-coated rigid foam panels

This type of board consists of a hard foam core, is reinforced with glass fiber fabric and coated with plastic-coated cement mortar. The very light, cement-coated rigid foam panels are moisture-resistant and dimensionally stable under thermal and hygric stresses. As a rule, they are used as a tile base (for example, tub cladding, molded parts), but can also be plastered or filled. Product examples: “Jackoboard” from Jackon Insulation, building boards from Lux Elements or wedi.

Dry expansion of wet rooms: dry screed elements

The decisive breakthrough for dry construction on the floor of wet rooms was achieved by screed systems made of cement-bound boards. The lightweight concrete panels with sandwich structure reinforced on both sides with an alkali-resistant glass mesh fabric can be used in addition to moisture exposure classes 0 and A0, in particular for moisture exposure classes A.

For the installation of floor-level showers, some manufacturers offer system-compatible floor drain systems as a complete system. This largely eliminates weaknesses that often result from a mix of elements that do not conform to the system.

Which record for what?

Even if the areas of application of the panels are listed above, the question remains as to when and which panel can / should be used sensibly for the dry removal of damp rooms. Cement-bonded slabs, for example, allow the complete bathroom expansion from ceiling to wall to floor in all load categories. However, the expansion with cement-bound boards causes higher material costs. The following considerations could be helpful in choosing the right plate from an economic point of view.

If guest toilets, utility rooms and domestic kitchens do not have a floor drain, they are not wet rooms. Then there are no restrictions on the use of gypsum or cement-bound boards. Both can be used here without composite sealing.

You also have free choice of plates "in rooms in which service and cleaning water is not used very often", such as B. in domestic bathrooms, bathrooms of hotels, floor areas with drains in these applications (stress class A0). In these cases, gypsum boards require a composite seal, cement-bonded boards can - depending on the application - be carried out on walls without them.

Gypsum boards are ruled out "in rooms in which service and cleaning water is used very frequently or for long periods of time" (stress class A). This includes bypassing swimming pools and public and private shower facilities. Cement-bonded slabs can be used with a composite waterproofing in these cases.

These considerations make it clear that gypsum boards are a suitable building material, especially in residential construction or in residential buildings. Cement-bound panels, however, significantly expand the application options for drywall in sanitary rooms. In addition, when using cement-bound boards in the area of domestic baths directly exposed to water, there is no need for a full-surface seal, as is necessary with plasterboards. It is sufficient to seal only in the corners and in the area of the fittings. This can make the use of cement slabs economical again, despite higher material costs. Cement-coated hard foam panels, in turn, score points in particular due to their low weight, which can be interesting for structural reasons, for example, when renovating old buildings. In addition, the foam core has a heat-insulating effect. The choice of panels therefore depends on many factors and must always be adapted to the respective requirements - and not least to the client's budget.

Beyond the plate

Conventional hot-dip galvanized drywall profiles can be used to expand domestic bathrooms. In the case of heavy moisture or when there are corrosive substances such as sulfates or chlorides (e.g. in swimming pools, canteen kitchens, laundries, etc.), special corrosion-protected profiles are available. These are coated with an acrylic or epoxy resin coating. They can be easily distinguished by their color (e.g. black or blue).

Filler and surfaces

With the leveling compound, on the other hand, it is advisable not to do without "damp room equipment" even in the area of domestic bathrooms. In rooms in which the relative humidity only briefly exceeds 60 percent during the day (e.g. in domestic bathrooms and comparable rooms), the usual z. Some impregnated fillers are used (eg "Uniflott impregnated" by Knauf, "Vario impregnated" by Rigips). In general, the leveling compound should be matched to the board used. If you follow the manufacturer's recommendations, you are on the safe side.

For the production of coatable surfaces on a wide variety of substrates common in damp areas, e.g. B. Gypsum boards outside the tile mirror, but also for plasters or for filling over tiles, special fillers are offered (eg "Knauf Estetico Universal"). The combination of a very low water absorption capacity of less than three percent in combination with tested mold resistance ensures that mold is avoided even in extreme conditions. The very fine, smooth and mold-resistant surfaces that can be produced with the filler can then be provided with suitable, customary paint systems.

Everything tight?

Floor and wall surfaces that regularly come into contact with water (shower area, walls above the sink and bathtub, walls and floors in public bathrooms) must be sealed. This creates a waterproof, stretchable layer that prevents water from entering the drywall construction. For example, a spreadable seal (also called liquid film) can be used for this (eg "liquid film" from Fermacell, "Knauf Flächendicht", Rigips "liquid sealing film"). In the corners and at connections to sanitary objects, a sealing tape belonging to the paint is placed in the freshly applied liquid film, as well as on pipe ducts. Ready-to-use cuffs are available for this. The tissue is then covered with the liquid film. After a drying time of at least one hour, a second application is made.

Leaflet 5 of the gypsum industry can be found here:

PraxisPlus

Further information on the

products mentioned in the text:

www.fermacell.de

www.jackon-insulation.com

www.knauf.de

www.luxelements.com

www.rigips.de

www.siniat.de

www.wedi.de