Paint and other coating may need to be removed for many different reasons. When intending to repaint, preparation is the most important step because a new coat of paint is only as stable as the surface underneath. Therefore, if the old paint is peeling, flaking or chalking (fine chalklike powder comes off when you rub your hand across the surface), the old paint must be removed before new can be applied or it will not adhere.
Styles change as well. A previous homeowner may have painted over brick or wood that a new homeowner would like stripped back to the natural material.
The best method to remove, or “strip” paint from any surface with the least possible damage depends upon the substance that was painted and the type of paint used. Sandblasting is a well-known way to remove paint from metal and other hard surfaces such as concrete, but particles made of other materials such as plastic and ruby can also used to remove paint and other coatings from sheet steel, aluminum, magnesium, plastics, fiberglass band high tech composites more gently than traditional sand without etching, pitting or warping the underlying surface.
Care must be taken when removing paint from many surfaces to avoid damage. Power washing—spraying water under extremely high pressure—can remove paint from wooden, masonry (stone, brick, etc.), and concrete exteriors. Anyone can use a rented pressure washer, but a professional is trained to choose the right nozzle, temperature, and pressure for each situation and can remove much more paint than a novice without damaging the surface underneath.
In the case of furniture and cabinets, improper stripping can raise the grain of the wood, requiring extensive sanding. Stripping by applying a chemical substance to dissolve the old paint so it can be wiped or scraped away is usually the preferred method on fine wood. This method may also be necessary to remove paint from old brick buildings constructed several decades ago. Common clay bricks used then are softer and more porous than today’s high-fired bricks and could be damaged with power washing.
Graffiti removal takes a combination of strong measures (to get the paint off) and a deft touch (to minimize over-cleaning, which leaves a patchy appearance).
Lead, which was used in the manufacture of paint until the late 1970s, is poisonous if ingested, inhaled or absorbed through the skin. If any of the paint to be removed was applied before 1980, it must be tested for lead. Lead based paint may only be removed and disposed by licensed abatement specialists according to Environmental Protection Agency approved methods.