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Moisture Resistant MDF - Is it Always Green?
June 22, 2016
21249
Moisture resistant MDF is a highly versatile material specifically engineered to withstand humid conditions. One of the distinguishing features of moisture resistant MDF is its colour; it is often green or has a green core, which helps to easily identify it among other types of MDF.
Designed to provide durability and strength, moisture resistant MDF is perfect for use in environments with high humidity, such as kitchens and bathrooms, where traditional MDF might fail. This article will delve into the characteristics, applications and benefits of moisture resistant MDF, highlighting its key features that make it an excellent choice for both professional and DIY projects.
What is moisture resistant MDF?
Moisture resistant MDF is a sheet material manufactured from compressed wood fibres that are combined with resin to form a panel.
MR MDF has a high internal bond strength, which makes it very versatile and suited to interior applications such as furniture manufacturing and mouldings like skirting boards, architrave, and window boards.
The moisture resistant properties of this MDF mean it can be used in areas that may be subject to occasional wetting or humidity.
What are the benefits of moisture resistant MDF?
Moisture Resistant MDF boasts high internal bond strength, ensuring it retains its form and stability in challenging conditions, which makes it durable for construction and furniture applications. Manufactured with moisture-repelling resins, this MDF enhances its resistance to humidity and wetness, effectively preventing moisture absorption in environments with fluctuating humidity. It is available in various thicknesses to accommodate different project specifications, making it suitable for both large and small-scale applications.
This material is user-friendly for carpenters and DIY enthusiasts, as it can be easily cut, shaped, and customised into various designs. It holds fasteners well, ensuring sturdy construction and assembly, and features a smooth, free-knot surface that allows for easy finishing with paints, stains, or varnishes. Moreover, Moisture Resistant MDF is denser than standard MDF, providing additional durability and a premium feel.
Why is some moisture resistant MDF green?
MDF manufacturers produce a range of MDF sheet products with differing specifications and properties to suit a varied customer base.
One of the largest markets for MDF sheet material is in building and construction. Companies in this industry need to easily tell different grades of MDF apart visually when on site.
To help with this, MDF manufacturers added a green dye to moisture resistant MDF sheets so they could be identified easily.
Building and construction trades use a lot of 8’ x 4’ and 10’ x 4’ MDF sheets, so nearly all moisture resistant MDF in these sheet sizes will be green or have a green core.
The green dye that is added to MR MDF is purely for identification purposes and has no moisture-resisting properties itself. The resistance to moisture comes from the resin that is used to bond the wood fibres together during the manufacture of the MDF sheets, which differs from that used in standard grade MDF.
Can you get moisture resistant MDF that is not green?
Larger sheets of moisture resistant MDF (generally 14’ x 4’ and upwards) are brown in colour like a standard MDF and have no green dye added to them.
One of the main markets for larger sheets of MDF is in the manufacture of moisture resistant MDF skirting boards and other interior mouldings.
Because these products will be painted, it is much better for skirting board manufacturers to work with MDF that doesn’t contain a dye. Green MDF requires more work and primer to make sure the surface of the product is fit for painting, with no green colour bleeding through to the surface.
10 years ago, at the request of the skirting board industry, green dye was no longer put into the larger MDF sheets because manufacturers found that it was taking a lot of primer to fully cover the green colour, which significantly increased production costs.
Is all MDF moisture resistant?
No, there are many variations of MDF for a vast range of uses, so not all MDF is moisture resistant. Below is a short summary of the different types of MDF and their uses:
Do you need to prime moisture resistant MDF?
If you plan to paint anything made from MDF, whether it is moisture resistant or not, it will need to be primed first.
MDF needs to be primed to seal the MDF so that a topcoat of paint does not sink into the MDF material. Priming also allows for a quality final paint finish by creating a smooth surface on which the paint will be applied.
Is moisture resistant MDF waterproof?
Moisture resistance is not the same as waterproof. Moisture resistant MDF is not a fully waterproof material; it cannot be submerged in water or used in areas where it would get very wet, like outside in the rain for example.
Moisture resistant (MR) MDF is designed to function in humid areas where moisture is present in the air without ‘splitting’ or ‘flaring up’. Direct exposure to water can lead to warping and swelling, so caution is advised in environments where it may come into direct contact with water. Be sure to read this article for more information on how moisture resistant MDF skirting boards can be used in a bathroom.
How do you seal moisture resistant MDF?
To seal moisture resistant MDF effectively, it is important to follow a series of steps that improve its durability and protect it from moisture damage.
First, ensure that all surfaces of the MDF are clean and free of dust. This preparation is crucial for achieving a strong bond with the sealing products. Next, select a suitable sealing product, such as a water-resistant primer or sealant, designed specifically for MDF. Look for options that offer moisture resistance and, ideally, are formaldehyde-free to promote healthier indoor air quality.
Once the appropriate sealant is chosen, apply a thin, even coat to all edges and surfaces of the MDF using a brush or roller. Pay particular attention to the edges, as these areas are more susceptible to moisture absorption. Allow the first coat to dry completely before sanding lightly with fine-grit sandpaper to ensure a smooth finish.
After sanding, apply a second coat of sealant for added protection. Again, let it dry thoroughly. For optimal results, consider applying a topcoat of paint, stain or varnish that is also moisture-resistant, as this will further enhance the surface's durability.
About the Author
Kieron Miller is the Managing Director of Skirting 4 U and has been working in the skirting board and online retail industry since 2012. Kieron has been using his extensive product knowledge and problem-solving experience to help both trade and private consumers all over the country find the perfect skirting board products for their projects. He continues to innovate new solutions and product ideas as the market continues to grow.