Scrape off the old paint I'm pretty sure they had wall painting in mind when they said it. Do you need to scrape off all old paint before painting? The universal answer is No, it's not necessary. You just need to remove all the paint that has failed. Most often, the newly selected problem areas, where the paint has been compromised, must be removed.
New paint may not adhere properly to walls and there is a greater chance that newly painted walls will develop defects. Check your painted walls by inspecting them for any signs of bubbling, cracking, or peeling. A very powerful and professional-quality infrared tool, the Cobra is small and versatile, about half the size of the IR stripper, and stands out to fit into small, windowed spaces. Turn down the heat and add some moisture and you'll get an effective, old-fashioned way to remove paint that helps remove excess dust (which is what makes removing lead paint dangerous).
Working on 26% cladding, windows, vespers, ceilings, it may be necessary to scrape off all old paint before proceeding with paint preparation. If your walls have paints that are peeling off, be sure to scrape them off and remove any pieces that will peel off. Whether you switch from a painted finish to a varnished finish or from an oil-based finish to latex or any combination of these, you'll get better results if you remove old finishes and start over. After this, sand the filled areas so that the surface is even, applying a new coat of paint.
For example, a customer told me that someone had painted latex paint on oil without priming first. Know that you're not trying to peel off the paint by washing it, but sometimes loose paint will come off if the water is under high pressure. While repainting existing paint saves homeowners time and money, sometimes it's unavoidable to remove old paint for great results and a long-lasting paint job. What I'm saying is that, while you'll definitely get a better product with a full strip and restoration treatment, the conditions may not justify the enormous amount of work involved in peeling paint.
It's a good choice when old paint starts to fade, peel off, develop stains, mold, or other defects. It is necessary to replace old paint of lower quality with one that has a shiny and durable finish, people get bored of old paint and need to change it, or when moving to a new house previously occupied by someone else. Painting on walls painted many years ago may not seem uniform and pleasant, leading to a waste of time, money, efforts and resources. You may have to scrape off the remaining parts a little more, and the walls may still need to be sanded before priming and painting the walls.