In what cases can tiles be laid on gypsum plaster

Tiles are a popular option for both walls and floors when remodeling a space. On the other hand, you may be wondering if it’s okay to lay tiles directly on gypsum plastered walls. Although gypsum plaster provides a level and smooth foundation, it’s important to know when to tile over it.

The choice to tile over gypsum plaster is influenced by a number of variables, including the plaster’s state and the location of the tile installation. Gypsum plaster can make a great base for tiling in certain situations, but in other situations, further preparation may be required to guarantee proper tile adhesion.

Let’s examine the circumstances in which tiling over gypsum plaster is possible as well as the things you should know before beginning the project.

Is it possible to lay tiles on gypsum plaster

We take into account all the necessary information regarding the installation of tiles on gypsum plaster prior to renovations.

The following scenarios require the solution of this issue:

• if the owners got an apartment with damp rooms already plastered with gypsum;
• before renovation, the decorators did not inform the customer that it is undesirable to use gypsum mixtures in rooms with high humidity;
• gypsum was chosen for machine plastering.

You may be convinced to use gypsum compositions by the manufacturer’s instructions on the packaging, which indicate that this mixture can be used even in high humidity areas. Trusting people is not always a good habit. It’s possible to glue anything to anything, but what happens when tile cladding is installed over a gypsum coating?

Reasonably competent and responsible craftsmen do not suggest the gypsum-tile finishing option because of three important considerations:

• low strength of the gypsum coating;
• unsuccessful combination of materials with different expansion coefficients (the factor is triggered by temperature jumps, the greater the range of fluctuations, the faster it manifests itself);
• the favorability of the moisture-absorbing gypsum coating as a habitat for microorganisms, mold, fungus.

Additionally, there are circumstances in which using gypsum binder compositions is advised, such as when the base is composed of:

• gypsum;
• foam concrete;
• tongue and groove slabs;
• aerated concrete;
• expanded clay concrete;
• slag concrete.

These substances are low-strength, weak bases. The materials cannot withstand the tightening internal stress that results from the cement mortar that has been applied to them hardening. As a result, fissures appear, and the base and cement plaster plates eventually chip. Gypsum is lightweight, doesn’t shrink, and adheres firmly to flimsy surfaces. It will be necessary to glue tiles onto gypsum plaster in such circumstances. Experts favor blends that are assured to be of a high caliber, like Rotband.

Disadvantages

The following are some of the current drawbacks that make installing tiles on gypsum material not advised:

• gypsum coating is porous, which complicates uniform fastening of finishing materials;
• low strength of bonds in gypsum material limits the weight of finishing materials applied on top;
• the porous nature of gypsum plaster promotes rapid absorption of water droplets from the air, when wet, gypsum material loses strength;
• the humid environment created in the plaster is favorable for the development of various microflora.

Advantages

Materials made of gypsum plaster are distinguished by:

• high plasticity at the laying stage;
• shrinkage-free;
• easy formation of a smooth surface, immediately suitable for painting (without puttying);
• low coating weight with the same layer thickness;
• high vapor permeability, facilitating the "breathing" of the walls;
• the ability to retain heat is higher than that of cement plasters.

How to glue tiles on gypsum plaster

We examine the process of laying tiles on gypsum plaster to ensure a firm and long-lasting finish. There is technology that is impervious to breach.

1. First, they prepare for gluing the plaster itself.
2. Carry out marking.
3. Glue (row by row) ceramic plates.
4. Groove the seams.
5. Let the glue gain strength.

How to prepare gypsum plaster for tiles

Let’s assume that the coating holds firmly based on the findings of the tapping and inspection. Although it has minor flaws like cracks, potholes, open joints, and stains, it can still be used.

There are several sequential operations that make up preparation:

1. Potholes, depressions, cracks are repaired. Protrusions are ground down using a grouting mesh.
2. The surface is cleaned of stains. If the stains are not only on the surface, but have “eaten into” the plaster layer, the plaster layer is removed at the spot of the stain, after which it is covered with a plaster mixture.
3. Remove unnecessary hardware, isolate the remaining ones.
4. Remove dust.
5. If the room has a normal humidity regime, and the cladding is ordinary tiles, the plates of which weigh little, apply a primer composition that penetrates deeply into the pores (deep penetration). The primer is applied in 3-4 passes. This mixture will strengthen the gypsum surface. Each of the applied layers is necessarily dried.
6. To ensure reliable adhesion, increase strength (when using porcelain stoneware), apply a thin layer of tile adhesive with rubbing movements.
7. Finally dry.
8. Make markings.

To strengthen the finish, you must additionally install and fix a galvanized mesh on the wall’s surface if you plan to face it with porcelain stoneware.

Gypsum plaster cannot be leveled using tile adhesive. The total thickness of the adhesive layer and ceramic tiles should be less than the plaster’s thickness. For leveling, only plaster is utilized.

Features of preparing walls in wet rooms

Applying a waterproofing agent is one of the steps in the "dry scenario" for laying tiles on plaster in a bathroom that is going to be clad. That is, two to three layers of waterproofing are applied in bathrooms following a similar priming procedure (experts advise using liquid mastic, which is available in buckets). The preparation work is finished when it is dry once more.

Not all waterproofing materials are appropriate for covering gypsum walls; for instance, cement waterproofing is not a good fit. When cement "meets" gypsum, it acts chilly. The substances that break down cement stone can be separated from the gypsum composition; in exchange, etricingite, a new "swelling" mineral, forms at the point of contact. The layer containing cement no longer adheres to the gypsum nearly at all. Consequently, different waterproofing compounds—polymer, acrylic, or bitumen—are used.

Similar to paint, mastic compounds are applied with a brush (or roller). The following mastic layers are applied in the intersection at the same time. This enables you to obtain a flat-thickness waterproofing film. Mastic compounds are chosen based on the tile glue’s composition, which is determined by the ceramics’ size and composition, respectively. Making a compositional error will eliminate all of the works. Pay close attention to the manufacturer’s stated purpose for the funds.

Laying tiles on gypsum plaster

This phase starts at:

• mechanical damage and stains of the plaster coating are eliminated;
• strengthened the plastered surface of the wall, increasing its strength;
• reduced the ability of the surface to pass moisture into the plaster layer;
• increased the adhesiveness of the surface so that the tiles stick tenaciously and securely to the gypsum plaster using glue;
• the kitchen or other room to be tiled is marked out.

When marking out, remember that only complete tiles should be used in the upper row when tiling the wall all the way up to the ceiling (halves ruin the visual impression).

The tile adhesive preparation will come next. For interior work, it makes more sense to use a ready-made composition, as the adhesion quality will be adequate to glue the tiles "tightly." Additives that are antiseptic and water-repellent are typically found in ready-made compositions. Make sure the glue is ready by following the directions.

The tiles are adhered to in this order:

1. A galvanized guide profile is mounted horizontally on the wall, on which the tiles of the second row (in a row) from the floor will be placed.
2. The glued side of the tile is moistened (this prevents the tile adhesive from dehydrating).
3. Apply tile adhesive to the glued side of the tile with a spatula, then level the adhesive with a notched trowel.
4. Glue the tile to the wall, pressing evenly along the plane with your hand. If you need to align it according to the adjacent one, use a short level, like a bar.
5. Remove excess protruding mortar (the remains are easily washed off).
6. Install crosses that regulate the size of the seams between the tiles.
7. Lay the outer (cut) plates in the corners last.
8. You can lay the tiles in 3 rows at a time, after which take a break for the adhesive to gain strength. Otherwise, under the weight of the cladding laid above, the lower one will creep.
9. Fill the first row last, removing the profile.
10. Let the glued tile harden for a day or more. Then grout the seams.

Is it possible to lay tiles on undried plaster

A very bad idea would be to glue moisture-tight tiles onto a plaster layer that hasn’t dried. There might be wet material beneath the crust even if the layer appears dry from the top. The fact that fungi will grow and the tile will obstruct moisture escape is not the issue. Compared to dry gypsum, wet gypsum is twice as weak and less resilient. As a result, it’s essential to allow the plaster mixture to dry entirely naturally (without heating and fans). One centimeter of coating typically takes five to seven days to dry; this time varies depending on the humidity and room temperature.

If you’re thinking about tiling over gypsum plaster, you need to make sure the surface is ready. Although it’s not always the case, properly primed and cured gypsum plaster can offer a sturdy foundation for tiles. It’s important to consider factors such as the type of room, exposure to moisture, and plaster condition when assessing whether tiling directly over it is a viable option.

Extra care must be taken in damp areas, such as kitchens and bathrooms, to avoid future issues. It is frequently advised to apply a waterproof membrane or sealant to shield the gypsum plaster from moisture. It can be simple and efficient to tile over gypsum plaster in areas that aren’t exposed to a lot of moisture.

In the end, the choice will be made after evaluating the particulars of your project. A sturdy and long-lasting tile installation can be achieved by taking the time to assess the plaster’s suitability and making the required preparations.

In certain situations where the gypsum plaster has dried completely and bonded to the wall securely, tiles can be placed on top of it. The surface needs to be level, dust-free, and free of loose particles. Furthermore, the moisture content of the space should be moderate because gypsum plaster is not recommended for extremely moist areas like bathrooms. A stable base for tiling can be created with properly prepared gypsum plaster, assuring good adhesion and long-lasting results.

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