Water Damage and Paint

Have you had a leak in your roof causing water damage to your drywalled stippled ceiling ?

When moisture permeates through drywall or plaster ceilings, the textured finish will normally become loose and flaky. To repair this, it is very important to scrape off all the loose texture back to the area where it is stable. Remove all dust with a damp towel and apply a coat of Weldbond adhesive, diluted 3 parts water to one part Weldbond to the area where the stipple was removed. When dry, apply a roll coat of Homax Texture Finish, selecting the one to match your existing ceiling texture. This may require two applications if the thickness of the existing ceiling is to be met. Leave for 12 hours to cure. Now the ceiling should be painted to give a uniform colour. Ceiling paints such as Pro Fresh Ceiling Paint availble at Cloverdale Paint Stores, will give excellent results as it will cover water stains and blend the old with the newly patched area. Before painting, prepare the ceiling by applying a masking skirt paper around the perimeter protecting the walls from the ceiling paint. Paint should be applied with a slit foam roller.

Paint is any liquid, liquifiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film.

Paint is used to protect, decorate (such as adding color), or add functionality to an object or surface by covering it with a pigmented coating. An example of protection is to retard corrosion of metal. An example of decoration is to add festive trim to a room interior. An example of added functionality is to modify light reflection or heat radiation of a surface. Another example of functionality would be the use of color to identify hazards or function of equipment and pipelines.

As a verb, painting is the application of paint. Someone who paints artistically is usually called a painter or artist, while someone who paints commercially is often referred to as a painter and decorator, or house painter.

Paint can be applied to almost any kind of object. It is used, among many other uses, in the production of art, in industrial coating, as a driving aid (road surface marking), or as a barrier to prevent corrosion or water damage. Paint is a semifinished product, or intermediate good as the final product is the painted article itself.

Paint can also be mixed with glaze to create various textures and patterns. This process is referred to as faux finish and is quite popular with discerning homeowners, architects and interior designers.

When primers are used

Primer is a paint product that allows finishing paint to adhere much better than if it were used alone. For this purpose, primer is specially designed to adhere to surfaces and to form a binding layer that is better prepared to receive the paint. Because primers do not need to be engineered to have durable, finished surfaces, they can instead be engineered to have more aggressive filling and binding properties with the material underneath. Sometimes this is achieved with specific chemistry, as in the case of aluminum primer, but more often this is achieved through controlling the primer’s physical properties such as porosity, tackiness, and hygroscopy.

In practice, primer is often used when painting many kinds of porous materials, such as concrete and especially wood (see detailed description below). Priming is mandatory if the material is not water resistant and will be exposed to the elements. Priming gypsum board (drywall) is also standard practice with new construction because it seals the wall and aids in preventing mold. Primers can also be used for dirty surfaces that, for some reason, cannot be cleaned, or before painting light colors over existing dark colors.

Primers for wood

There are several reasons why using a primer before painting wood is mandatory. First of all, wood is very porous and will absorb the solvent from paint, drying the paint prematurely. As most paints undergo chemical reactions during the process of curing (for example, latex and alkyd-based paints actually polymerize when curing), they depend on water or solvent being evaporated slowly rather than being absorbed quickly by the underlying material. A layer of primer will help the paint to undergo proper complete curing cycle.

Secondly, without a primer, several layers of paint (as many as eight) can be necessary to completely obscure the wood grain and ensure even color. In general, primers are anywhere from 10 to 75 per cent cheaper than paint, and using a primer prior to painting is more economical. It also helps to obtain an even color, as wood is not uniform.

Lastly, if wood is exposed to moisture, a thin layer of paint will still be water permeable. The end result will be warped parts, mildew, and dry rot. Primer adds to the waterproofness of the paint.

Primers are not necessary for a wood stain treatment that is designed to show the wood grain.

Primers for metal

Some metals require a primer (such as un-treated aluminium) while others may not. A primer designed for metal is still highly recommended if a part is to be exposed to moisture. Once water seeps through to the bare metal, oxidation will begin (plain steel will simply rust). Metal primers may contain additional materials to protect against corrosion, such as sacrificial zinc.

Metal hydroxides/oxides do not provide a solid surface for the paint to adhere to, and paint will come off in large flakes. Using a primer will provide extra insurance against such a scenario. An additional reason for using a primer on metal could be the poor condition of the surface. A steel part can be rusty, for example. Of course, the best solution is to thoroughly clean the metal, but when this is not a viable option, special kinds of primers can be used, which chemically convert rust to the solid metal salts. And even though such surface is still lacking in comparison to the shiny clean metal, it is yet much better than weak, porous rust.

Painting and gluing aluminum is especially important in the aircraft industry, which uses toxic zinc chromate primers and chromating to add the necessary adhesion properties.

Primers for plastic

Using a primer on surfaces made of plastic is really only necessary when making a drastic change of color (going from dark brown to white, for example), as most household plastics are not very porous and are not easily damaged by moisture; or when a long-lasting coat of paint is desired. A primer will reduce the number of layers of paint necessary to completely cover the previous color, and will help the paint make a thorough bond with the surface being painted. As most paints and primers designed to be used for painting plastics are not water based, an important point for choosing a primer for plastic is making sure the primer’s propellant or solvent will not dissolve or warp the plastic part itself. Be sure to test both primer and paint on a small hidden spot of the part you are painting.