When we plan to lay tiles on the walls, we often encounter the problem of old oil paint or paneling, which is not an ideal surface for tiles. How to prepare the walls so that work with tiles goes smoothly? Here are the steps worth taking.
1. Assessment of the Condition of Paneling and Paint
Before we start laying the tiles, we must carefully assess the condition of the existing layers of paint or paneling. If there are many layers of paint and there are numerous cracks and places where the paint is peeling or falling off with the plaster, it is necessary to completely remove it. Removing such paint can be difficult and time-consuming, which is why specialist teams usually decide to rough the surface with a grinder or slotting machine. These grooves, approximately 5 mm deep, then cover at least 60% of the wall surface. In the case of weak plaster, it is worth increasing its strength by covering the grooves twice with a primer. The cavities are then filled with flexible adhesive mortar.
2. Preparation of the Subfloor in Poor Condition
If the substrate is in very poor condition, crooked or covered with weak lime plaster that crumbles when touched lightly, the paneling and plaster must be removed until the wall is exposed. The room should then be plastered again. The plaster is applied to the dusted and primed substrate with a layer up to 2 cm thick. There is no need to smooth the freshly applied plaster, as the coarse-grained surface holds the tile adhesive mortar better.
3. Preparation of the Substrate with a Thin Layer of Paint
If the paint layer is thin and adheres strongly to the cement-lime plaster, it is usually enough to matt the paint surface with coarse-grained sandpaper. To improve the adhesion of the substrate under the tiles, you can gently cut the paint with a sharp scraper or chisel until the plaster is exposed.
4. Selection of Adhesive
A flexible adhesive mortar is used to attach tiles to strong layers of paint, provided the surface has been properly prepared.
5. Alternative Method
If removing old coatings is too burdensome, an alternative method can be used. We level the surface with waterproof (green) plasterboards. To do this, drill 5 cm diameter holes in the plaster at 30 cm intervals, reaching to the surface of the bricks. We fill these holes with excess plaster adhesive mortar so that mortar cakes are formed on the surface. Then we glue the plasterboards to these cakes. We can additionally strengthen the mounting of the boards with expansion bolts for quick installation in some holes. After grouting the board joints and impregnating the surface, we can start laying the tiles. This technology is much less burdensome than removing plaster, and you can start laying tiles the next day after laying the plasterboards.
Laying tiles – summary
Preparing the surface before laying tiles is a key step in the finishing process. Appropriate preparation guarantees that the work will run smoothly and the final effect will be lasting. Therefore, it is worth investing time in proper preparation of walls and choosing appropriate materials for mounting tiles. Thanks to these steps, we can enjoy a beautiful and durable finish in our room.