If you have rafters in your commercial building that needs to be painted, you might be wondering just what needs to be done to get them looking great. Many businesses have opted to have exposed rafters, resembling a more postindustrial, open feel. When you have presented rafters, maintenance on them can be relatively minimal once you have the right coating or paint applied.
Types of Rafters
There are mainly two types of exposed rafters. They are:
Steel – This type is used the most and the steps needed to paint them can depend on a few different things. The age and their exterior surface are major factors. Other things that can make a difference can be the kind of exposure that they might have – such as weather elements.
Wood – This type usually is either kept in its natural state, or sealed with a coating.
Preparation Steps
The first step that will have to be accomplished is cleaning the rafters. The area to be painted will need to be inspected first, as there can be a buildup of dust and oils. These issues will need to be taken care of, especially if it can produce a hazard.
This can be done by:
Steel –
- Media Blasting – The right type of abrasives are used, with special equipment, to blast off old paint or coatings and any rust that is on the surface of the rafters. By using this method, you will be able to achieve an optimal surface for the new paint to adhere to.
- Scrub or Brush – This is typically done by hand and can take longer. With a lot of elbow grease you can get the surface prepared, but it’s not optimal.
- Sanding – Can be used in conjunction with scrub and brushing, and may not give you the necessary peaks and valleys needed for the best adherence.
Wood –
- Media Blasting – Certain fine abrasives are perfect to use for this type of surface. Once this is done, you will be able to either leave the wood with the natural look, or you will be able to proceed to the next step. While it is recommended to use media blasting, you can use the scrub/brush or sanding methods, but they will not be as thorough.
Time to Paint
Now that you have gotten to this point, you will need to determine the right paint or coating for the job. Once again there are varying factors, such as environment.
Steel – Depending on your needs and requirements, the use of an alkyd primer might be needed. It will need to be topped with either more layers of alkyd primer, water-based acrylic paints, enamel, or some varieties of intumescent coatings. Alkyd primer should not be topped with any high-performance type paints like epoxy or polyurethane.
- Specialty Paints – When you apply paint or a coating other than a regular primer, it is classified as specialty paint, and when it comes to your rafters it is the better choice for functionality and presentation. The three main types that are used when painting rafters are:
- Zinc – There are two different types of zinc primers, which are inorganic and organic. The durable zinc primers help to protect the surface of the steel from rust. One coat of the inorganic primer is comparable to galvanization. The organic type is used in a multi-layered method.
- Epoxy – is a two-component paint and is a step up in protection from rust versus standard primers. They are a good fit for areas that are subjected to high humidity.
- Polyurethane – Is used as a finishing layer on top of either the zinc primer or epoxy coatings. It can also be applied without the use of a primer.
Wood – Since this type of rafter is not as widely used, we will briefly list some of the coatings that are used. These include: lacquer, various varnishes, numerous kinds of oils and water-based polyurethane. There are also timber stains that can be used if color is desired.
When dealing with rafters it is best to hire a professional to take care of it, as there are steps that need to be made to assure that it is finished to the highest standards.
