Preparing the substrate for painting

The first step is a visual and tactile assessment of the surfaces. Cracks, swelling, old flaking paint, streaks, stains, nails, plugs, loose filler, and differences in grain between different sections of the wall are identified. By tapping the surface, you can determine whether the plaster feels solid or hollow; if the latter is the case, it should be removed and refinished.

The cleaning phase is often overlooked but crucial. Dust, grease, smoke, and dirt accumulated over the years reduce the adhesion of new paint. Walls are dusted, and if there's significant dirt, targeted washing is performed, especially in kitchens, hallways, and areas near radiators and air vents. Any visible flaking paint is scraped down to the intact layer.

Cracks are treated based on their nature: superficial microcracks can be smoothed out with suitable fillers and products; larger cracks should be opened, cleaned, filled with specific fillers or fillers, and, if necessary, reinforced with fiberglass tape or mesh, especially along joints between different materials or in areas subject to movement.

Old, improvised filler , damaged edges, and holes left by plugs or fasteners are repaired with paste or powder fillers, then sanded to restore the surface to a uniform level. For heavily marked or uneven walls, it may be helpful to perform a thorough skimming , which eliminates differences in absorption and small undulations.

A key step is applying a primer or sealer suitable for the type of substrate: on new, highly absorbent plaster, it consolidates and evens out the surface; on old, dusty paint, it reduces flaking; on difficult substrates (plaster, drywall, mixed surfaces), it promotes even adhesion of the finish paint. Choosing the right product at this stage prevents stains and streaks due to uneven absorption.

In the presence of mould , the first thing to do is address the causes (condensation, poor ventilation, thermal bridges), then proceed with specific anti-mould treatments and appropriate cycles, avoiding simply covering with a "miracle" paint which, on its own, does not solve the problem.

Only when the surfaces are clean, intact, consolidated, and even does it make sense to move on to the actual painting. Good preparation allows the paints to work at their best and makes the difference between a result that lasts for years and one that quickly begins to show its limits.