Small hollows, faint streaks, battered panels … substrates are not always in great shape before painting. Yet it is exactly good preparation that will allow a perfect finish once the paint is applied. These preparatory plastering works are therefore essential for any renovation project where quality is expected. And to work quickly while achieving the best possible effect, mechanised application of plaster is indispensable.
Full-surface plastering
The first possible use enabled by mechanised plaster application is full surface plastering. It simply involves applying plaster in a single, continuous coat in order to obtain a smooth, uniform finish while reducing the time and effort required.
To do this, the painter proceeds in five steps:
- Preparing the surface: the professional checks that the surface to be coated is clean, dry and free of dust or debris. If necessary, they sand, clean and dust the surface themselves and allow it to dry for as long as needed.
- Preparing the plaster: once the substrate is ready, the appropriate plaster must be chosen for the type of surface to be coated. Some plasters need to be diluted more or less.
- Applying the plaster: two methods are possible. Professionals can opt for mechanised application — and its various possible variants, listed in this article — or manual application.
- Smoothing: whichever method is chosen, once the plaster is applied it must be smoothed. This step eliminates any imperfections and spreads the product evenly over the entire surface.
- Finishing: once the plaster begins to dry, it may be helpful to lightly pass fine abrasive paper over the surface to achieve an even smoother finish.
Because it prepares the substrate for paint by correcting small imperfections and irregularities, full-surface plastering is an integral part of the building painter’s trade. It is an essential step before painting, as it enhances the finish.
Joint tapes
Mechanised application is also increasingly used for coating joint tapes. These thin strips of paper that join plasterboard panels together must, like the surfaces, be coated before painting. This ensures that the entire surface is homogeneous and ready to be painted.
But coating joint tapes differs from full-surface plastering. Special plasters adapted to treating joint tapes are required, and different application methods are necessary, with mechanisation also possible here.
To lay a joint tape, the professional works in six stages:
- Preparing the surface: as with full-surface plastering, the substrate where the joint tapes will be placed must be checked to ensure it is clean and dry before proceeding.
- Preparing the plaster: every type of plaster has its specific use. Care must be taken to choose the most suitable plaster for the situation.
- Applying the plaster: in jargon this is called “buttering the tapered edges”. It means applying plaster to the tapered edges of each plasterboard panel to reinforce the bond between them.
- Placing and pressing the tape: on the freshly applied plaster, the joint tape must then be positioned and pressed down to remove the excess plaster.
- Second coat: after drying, a second pass, wider than the previous layer, is often recommended.
- Finishing: a final sanding step yields a higher-quality finish.
The care taken with joint tapes is fundamental if you want to obtain a quality end result in your renovation project. The plastering stage is therefore also essential here, and mechanisation can be very useful for improving the quality of the finish while reducing the duration of the work.
Advantages of mechanising plaster application
In recent years, mechanised plaster application has become widespread among building professionals, whether they specialise in painting or provide multiple services.
The reason is simple: this method has many advantages over manual application, starting with speed. With a machine, a professional coats a surface much faster than by hand. If working alone, they must sequence their work by applying plaster to one segment and then smoothing it; this is still faster than doing everything manually. If they have help, the plaster can be applied continuously, with a second person taking care of smoothing – and the time saving multiplies.
Mechanised application also avoids the repetitive movements of manual application, reducing the strain of the work for the professional. Associated risks such as musculoskeletal disorders – particularly the infamous “tennis elbow,” a tendonitis of the elbow well known to painters – are lessened.
With higher productivity and greater working comfort, mechanised plastering not only allows more jobs to be completed without having to hire additional staff (reducing costs and boosting turnover), but it also reduces fatigue. Moreover, there are several ways to use mechanised plaster application to your advantage, so that each site can adopt the most suitable method – as this article goes on to explain.