The first step in good maintenance
When we say that “maintaining, repairing and replacing” is at the core of a sound preservation approach, it especially means that painting is essential to a maintenance program. Woodwork, doors and windows, wood cornices and dormers, are all elements that need to be painted periodically.
Painting will ensure the best protection for your house and help it stand the test of time. It is also one of the few renovation works that can be performed by most of us… at least those of us who are patient and who find heritage preservation something worthwhile and fun to do.
Some materials are more durable than others. Slate, for instance, will last centuries without maintenance. Conversely, wood and metal are more easily damaged and will deteriorate after a few years if they are not maintained properly. Paint is the means to protect these materials.
The secret for success resides first and foremost in the work preparation. Generally, one must spend as much time preparing the work site as painting. It’s simple; the protection principle of paint is that it must form a watertight coating on the surface that needs to be protected. Hence, if you let the old paint flake off and crack, the painting preparation will be more involved because you will need to carefully scrape and sand the surface so it can then be covered in a uniform and watertight fashion. It is therefore a good idea to regularly repaint exterior wood and metal surfaces. Avoid painting them in full sun or when there’s a high degree of humidity. All new or stripped surfaces must first get a base coat. Also make sure that the new paint is compatible with the existing one.
The principle is to never let surfaces deteriorate; surfaces should always be watertight. If a cracked surface is repainted without sufficient sanding, the new coat of paint might look flawless at first but it will not be long before it starts crazing and all the work will have been done for nothing. The same goes for inadequate sanding that will prevent the paint from adhering properly to the surface leading to its peeling off in patches. Oil-based or water-based paint? It all depends on the surface to cover, so follow the manufacturer’s recommendations carefully…
The principle is the same as for wood. The surface to be painted must be well prepped and rust must be removed. Rust can be compared to tooth decay; if not taken care of, the metal surface will literally disintegrate with time. You must therefore start by inspecting all nooks and crannies followed by a careful scraping with a rigid metallic scraper or a metallic brush used by hand or attached to a drill (protective goggles are a must).
If scraping is not enough to uncover sound metal, you may have to use a chemical rust removal product to stop the process. You will then apply a metal primer and finally a finishing coat that will itself have antirust agents.