“My wood cladding” campaign: everything you need to know about the varieties of wood, natural, autoclaved slats, with or without finishing…

For new builds and renovations, different wooden claddings are available: natural, autoclaved, with finishes (saturator, paint, stain, oil)... Not easy to find a choice appropriate to the desire for design and durability? The “My wooden cladding” campaign - on the initiative of the Fédération Nationale du Bois (FNB) and Le Commerce du Bois (LCB), financed by France Bois Forêt and coordinated by the CNDB - whose mission is to promote the strong points wood material in its use in cladding for professionals and individuals, offers an overview of the different wood cladding solutions.

Individuals and professionals, essential prerequisites

Before any project, many criteria must be taken into account. The choice of the type of slats (planed or profiled, shingles or panels) and the type of installation (vertical “Scandinavian style”, horizontal “American style”, clapboard, clerestory or false clerestory) depending on the desired aesthetic rendering, for facades in keeping with the style of the building. On the implementation side, ensure compliance with current standards (DTU 41.2 “Exterior wooden cladding”) and manufacturers' recommendations. Comply with the Employment Classes defined in standard NF EN 335 which determines classes 3a, 3b and 4 wood as the most appropriate for cladding, depending on the level of exposure to humidity of the slats.

Natural wood cladding: the best environmental record

These are wooden slats without treatment or finishing, naturally durable. The main species are Douglas, Larch and Red Cedar. Natural wood cladding represented 20% of sales in 2019*.

Autoclaved wood cladding: promoting local wood

The process consists of injecting metal salts in aqueous solution into the wood, by alternating vacuum and pressure, which are fixed in the cells of the wood. The cladding is thus protected from insects and fungi with stability greater than 20 years. The main species are: Fir, Douglas and Pine. Autoclave cladding represented 51% of sales in 2019*. Apart from the autoclave, other treatments exist although less widespread: high temperature and oleothermy (vegetable oil bath).

Natural and autoclave wood cladding grays over time

This natural protective patina, under the effect of UV and bad weather, changes the appearance and has no impact on durability and maintenance. This graying is now better accepted, especially when it is done in a homogeneous manner.

Wooden cladding with finishes: mastering the aesthetics of the facade

Natural wood and autoclave wood can be treated with finishes to increase their protection against climatic aggressions (UV, rain), insects and fungi (fungicide). These finishes also aim to reinforce the aesthetic appearance of the cladding, either through a choice of shade or color for more personalization, or by slowing down the graying effect.

There are 4 main types of finishes:

For use in cladding, certain species are more suitable than others for receiving a finish, due for example to: their capacity for penetration, absorption and adhesion to a finishing system, their nodiness or the resin rate. Other species can be used purged of sapwood or treated according to the necessary use class.

The main resinous species are Spruce, Douglas, Larch, Red Cedar and Northern Pine.