Factory-painted and quality-assured external cladding

CMP is a certification system designed to provide quality assurance for industrially coated exterior timber cladding. The CMP system ensures compliance with tough standards for the timber, moisture content, paint and industrial coating process, to ensure the cladding boards are perfectly suited to their future function. Under the CMP system, every stage of the process is documented to allow traceability of individual cladding boards and to guarantee high quality. The paints used to produce CMP-approved cladding boards are tested by accredited third-party bodies to check they meet current standards and rules. The paints are specially designed for exterior wood and are applied under optimum conditions to the correct thickness to guarantee a uniform result and long service life. 


The long-term performance and appearance of decorative exterior timber cladding are determined with the very first coat of paint. Using CMP-approved cladding boards guarantees the coating has been carried out on a clean, dry timber surface that has been finely sawn a maximum of 12 months before painting. From fine-sawing to painting, and beyond, the cladding boards are packaged and protected from rainfall, sunlight, dirt and ground moisture. The timber quality of CMP-approved cladding boards is higher than regular exterior cladding. More stringent sorting rules limit the incidence of properties that have a negative impact on the paint’s ability to adhere and last. Coatings are applied under optimum factory-controlled conditions in even layers that give full coverage at just the right thickness. This means that the right amount of paint is used and a uniform result is achieved.

CMP-approved manufacturers conduct meticulous checks of the timber, paints, manufacturing process, packaging, storage and documentation. Both the entire process and the industrially coated cladding boards themselves are independently certified and regularly checked by external inspectors. 


CMP-approved cladding is ready to install and will need no more than one or two coats of paint on site, depending on which class of surface treatment is being used. The buyer thus saves time and money on painting, while also achieving a better result. The industrial coating protects the wood before installation, giving flexibility on when to finish painting the façade.

The high quality standards of CMP-approved cladding boards extend the maintenance intervals for the external wooden façade, as long as they are correctly installed and finished. A reduced amount of maintenance over the service life of the façade is a major factor in the overall economics of the investment and something that should be taken into account when choosing a façade material.

Surface treatment classes

Modern coatings are designed to follow an application system. This is because the properties of each coat in the system are optimised to achieve the required performance. CMP-approved cladding boards are individually labelled with information on what additional work is required to complete the painting system and finish the façade material. Each board is labelled with the surface treatment class, manufacturer and traceability number as assurance of correct manufacture, with clear traceability from production to end customer. CMP-approved cladding comes in two surface treatment classes for paints, irrespective of which colour is chosen.

Primed external cladding. The primer protects the wood against moisture and ensures good adhesion for the next coat of paint. After installation, external cladding classed as CMP-G should be finished with two coats of paint within 12 months. 

Primed and undercoated external cladding. The undercoat effectively protects the surface of the wood against the weather, mould and algal growth. After installation, external cladding classed as CMP-G/M should be finished with a top coat of paint within 12 months.


To ensure a long service life for CMP-approved exterior cladding, it must be correctly installed. The cladding boards should be installed in line with current building code focusing on correct cladding board orientation, correct fasteners and fastening and end grain coating.


CMP-approved cladding should be given its finishing coat or coats within 12 months of installation. Reducing the time between installation and painting minimizes the risk of the cladding being affected by its surroundings. When painting, always check the moisture content. The boards should have a surface moisture content of 16% or lower to ensure a good result and long maintenance intervals. Installed CMP-approved cladding should be given a visual inspection before final painting to check for any dirt or surface mould growth.

One of the finishing paints recommended at the time of sale should be used to ensure the compatibility of the various coats. For best results, the recommendation is to use the same paint system as was used for the industrial coating of the CMP-approved cladding. This is important for long-lasting protection and later maintenance needs.

End grain treatment is a crucial factor for the cladding boards’ service life and maintenance intervals. This should be carried out on site during the finishing work. The complete paint system must be applied to end grain and other exposed wood that might arise from sawing or mechanical damage etc.

The CMP system makes it easier for contractors and consumers to choose high-quality
facade materials.