What is MDF?

MDF is a popular engineered wood product that has become a staple in the construction and DIY industries. Made from finely compressed wood fibres combined with resin, MDF offers a stable and versatile alternative to traditional wood. This article will explore the characteristics, properties and benefits of MDF, helping you understand why it is a preferred choice for many building projects.

What is MDF?

MDF is an engineered wood product made from compressed wood fibres and resin, which creates a stable and reliable sheet material used extensively in the construction and DIY industries.

What does MDF stand for?

MDF stands for Medium Density Fibreboard. The word fibreboard refers to the way MDF is manufactured (from small wood fibre particles compressed together with resin to form a sheet material). The term 'medium density' describes how tightly packed the fibres are within the material compared to other fibreboard products like HDF (High Density Fibreboard) for example.

All of the MDF we use is industrial grade moisture resistant (MR) MDF. This is the perfect material for moulding skirting boards and architraves as it has an overall density that is around 15% greater than standard grade MDF.

What are the benefits of MDF?

One of the key benefits of MDF is its lower cost compared to real wood, making it a budget friendly option for those looking to create high quality furniture without breaking the bank. MDF can be laminated or finished to resemble genuine wood.

Another advantage is its smooth surface, which is free from the imperfections often found in natural wood. This allows for a clean and polished appearance, and MDF is less prone to size fluctuations due to temperature changes, unlike traditional wood.

Environmentally, it is a sustainable choice since it is made from recycled wood materials, helping to reduce waste. Lastly, MDF is easy to work with; it can be cut and drilled into various shapes without damaging the material, making it ideal for intricate designs and custom projects.

MDF density

The density of the moisture resistant MDF that we use is between 760-770 kg/m², with the density of standard grade MDF being around 650 kg/m² and lightweight MDF being around 600 kg/m².

MDF density is an important property to consider when manufacturing MDF mouldings for two main reasons:

1. Furring

As the MDF is passed through the moulding machine, the moulding is created by cutting away material to form the required design. This removes the smooth external layer along the detail and exposes the core of the MDF sheet. On a standard grade board, because the density is lower, the core is softer and can become furry. If this happens the board needs aggressive sanding to remove the loose fibres and re-seal the MDF prior to painting. If this is not done, the fibres will get trapped in the base coat of primer and leave a rough finish.

2. Porous core

In lower density MDF, the core is very porous. This means that when primer is applied, instead of settling on top of the MDF it soaks into the core. This means it needs multiple coats of primer before it is ready to be finished, which increases production time and adds significantly to the overall cost as so much more paint is required. Having the higher density MR MDF means the core is more stable so this problem is avoided.

What are the properties of MDF?

MDF is strong and durable, with a smooth outer surface that lends itself to painting.

The technical specifications and properties of the MDF are detailed in the table below. Kronospan is the main manufacturer of the MDF that we use, though we also use Medite depending on supply availability. The column on the far right of the table demonstrates how Kronospan MR MDF material used by Skirting 4 U stacks up against the EN specification (2nd right).

• Internal Bond. In the context of MDF skirting boards and architrave, the internal bond of the MDF isn’t massively relevant. The only time you would take this measure into consideration is when comparing different MDF specifications. The internal bond is a measure of how the MDF material performs in a stress test, and the resulting figure details how much force the board can endure before breaking. This is not the same as a test of elasticity.
• Swelling in Thickness, 24hr. This shows how the overall thickness of the MDF changes in a regular dry atmosphere after a 24-hour period within that environment. The MDF we use has a maximum swelling of 8% or 1.5mm, which is both minimal and 33% less than a standard grade MDF, which has a max swelling of 12%.
• Bending Strength/MOE (measure of elasticity). For both of these, the MDF sheets are tested by having several sheets stacked upon each other and force applied to the centre to find the point at which the material breaks. Skirting and architrave obviously aren’t load bearing products, so again this measure doesn’t apply here. It is useful when comparing specifications however. It is important to note that this does not mean the MDF we use is flexible enough to be bent around curved walls or bay windows.
• Internal Bond after Cyclic/Thickness Swell After Cyclic. This is a test carried out on all moisture resistant boards to see how they react to a humid environment. The boards are conditioned and then exposed to humidity for a period of time and the changes in the board are measured. The most relevant stat here is that the swelling of the board after the cyclic test is a maximum of 15%, or 2.7mm on an 18mm MDF board.

Is MDF safe?

MDF is a safe material to have in a home. There remains some concern over the safety of MDF because it contains the chemical Formaldehyde. However, this is a chemical that occurs naturally not just in all wood products, but even in people, food and trees! 'Normal' formaldehyde levels in a home are around 0.05 parts-per-million (PPM) and the MDF used for manufacturing skirting and architrave releases 0.1 PPM in line with European standards.

More information on the safety of MDF can be found here.

Working with MDF is a different matter, and it is vital to protect yourself against the very fine dust particles that enter the air when cutting or moulding MDF. To be properly protected, a respiratory mask with an air flow should be worn to minimise the risk of dust particles getting into the lungs or eyes. At skirting 4 U, we have invested heavily in protective masks for all factory staff to ensure they remain protected when machining MDF.

If you need any more information about anything related to our product or service, please contact our customer service team on the live chat, by email to enquiries@skirting4u.co.uk or give us a call on 01922 451 689.

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.