Special Wall cladding : wood versus composite

THE MANY ASSETS OF WESTERN RED CEDAR

A LIGHT AND YET RELATIVELY STURDY WOOD SORT IS PERFECT FOR A WALL

Roderik Vandervennet (Jadimex - B)

‘Also spreading out internationally.’

Jadimex, which is based in Lovenjoel (Korbeek-Lo, Belgium), is a specialist in wood, most of which is used for wall cladding. The firm is increasingly spreading out internationally, hence its forthcoming first appearance at the Carrefour Wood Show in Nantes.

We spoke to Roderik Vandervennet, technical and commercial manager of the back office and responsible for marketing at Jadimex. During the interview, amongst other things, Roderik explains why wood (and its derivatives) is the most suitable material for wall cladding and why composite is actually not the best choice available.

He starts by saying: ‘To make things clear, I should probably tell you something about what Jadimex is. We’re a family SME with eight workers. We started in 1996 literally with the sale of hardwood from the garage. Manager Danny Roelants sold this wood on the market because he noticed that there were no such vendors in Flemish Brabant. Gradually, the business grew and he set up a real timber trade. He tried lots of things, but it was invariably durable tropical hardwood which came to the fore. About two or three years ago, oak and thermally treated ash also joined the pack.’

Jadimex also has a link with Rumania. In the past, they made contact with someone in that country who wove hazelnuts. Roelants built up a factory there with new products. ‘Danny started production on a bigger scale, but about seven years ago, he noticed that there were more opportunities than working solely with hazelnut. And so, he bought a big saw machine for sawing tree trunks, including ash. With that ash he set up his own trademark under the name Jadiwood and business is good.’

Big demand for treated ash

‘What we’ve noticed is that there’s a particularly big demand for treated ash, which we dry and treat thermally in Belgium according to the highest standards. We still like to work with durable tropical hardwood, but we’ve found that there are two problems on the market. On the one hand, prices are rising all the time and, on the other hand, availability is a growing issue. And, let me say it before the critics intervene: Don’t forget that we work only with sustainable operators. Working with people who cut down trees completely is unthinkable for us.’

When the discussion proceeds from ash to wall cladding, Roderik refers to an essential element. For wall cladding you have to fit vertically, not horizontally. The conditions are completely different to those of a terrace, for instance. That’s one reason why composite isn’t such a good choice, plus the fact that treated wood is specifically more suitable.

‘Don’t forget that horizontally fitted wood needs to be very durable as it’s always under pressure. That’s not the case with a wall, which is “spared” to a greater degree. For wall cladding you don’t need such high durability, so the use of tropical hardwood is actually a case of “overkill”. You can also work with wood from classes two and three, such as oak and treated wood, and that camouflages the increasing insulation. I’d also like to mention that recently we’ve developed two blind fastening systems for exclusive sale in Belgium. The one system (Jadifix) has a small joint between the planks, whilst the other one (Jadeco) has no visible joint. This fits in with the circular construction narrative. If you move house, you can even simply take your wall with you.’

Composite swells in the length

Obviously, we also want to know why thermally modified wood is a good choice for wall cladding and composite isn’t. ‘The main reason why we don’t use it is the way in which composite swells and shrinks. It swells along the length, and quite considerably as well. You can count on 1cm per metre of length, so that with a plank of 5m you get a difference of 5cm between the summer and winter condition. You can resolve that with wider profiles on the sides, but it certainly doesn’t look attractive.’

Jadimex has been working for some time on the development of a web shop. Can Roderik tell us about that? And can he tell us about their very first participation in the Carrefour Wood Show? ‘The test phase finished by the end of April and we’ve taken orders late in April and early in May. The web shop is going online on 12 May.’ ‘The choice for Carrefour was logical because in recent years we’ve noticed how important this show is for our sector. As an importer and vendor of hardwood mainly to professionals, we have to attend because we also need to broaden our horizons internationally. Then, at the same time, we’re also thinking of our sawing machine in Rumania which has to operate as much as possible and for which we hope to concludes some contracts during and after the show.’

As you can read in the testimony, composite is not the most suitable choice for use as wall cladding. What is also equally clear in that same piece is that you don’t necessarily need tropical wood sorts for a wall. A wood in a durability class between one and even three will suffice due to the specific place of a wall. And so, which type of wood can you use? One of the candidates is certainly western red cedar, which is sufficiently durable with its class two grade.

The properties of western red cedar or thuya plicata, which grows between 39° and 57° latitude mainly in the Canadian province of British Columbia, make it ideal for outdoor use on a wall. It is a light and yet relatively sturdy and resilient North American softwood sort, which is highly resistant to rot and weathering. It also makes for some unique colour variations, which range from light yellow-brown over pink-brown and salmon colour to chocolate brown, with charming slab flames.

Apart from walls, you will also find this type of wood in outdoor applications like shingles and shakes, profiles, roof edges, window frames, pergolas, greenhouses and light constructions, and even terraces. What’s interesting is that cedar is very often left untreated outdoors because the wood ages beautifully and naturally. If you don’t want the wood to age, there are colourless products to treat cedar cladding which are applied in two or three coats, ‘wet on wet’.

Various qualities

It’s good to realise that western red cedar is imported in various qualities. Here we draw a distinction between No 2 Clear and Better (almost faultless with rustic lines), No 4 Clear (with a number of flaws which can easily be sawn off, of sufficient quality for most applications), Factory Flitches (80% faultless items which can be sawn shorter, suitable for items such as garden furniture), Tight Knotty (sturdy gnarl quality: wood with an unlimited number of sturdy gnarls, for instance, for terrace planks), and Standard and Better (of somewhat lesser quality, but excellent for pergolas, support beams for terraces, or diverse constructions).

Drying and processing

Western red cedar dries easily, especially in small cross-sections, and there’s little risk of distortions. The processing, too, certainly isn’t complicated, either mechanically or by hand. The dust which is thereby emitted sometimes causes irritation, so it’s best to provide good dust suction. Don’t forget, too, that wood early in the season is soft and that you should avoid compression by applying only moderate pressure to the work surface with a sharp tool, especially with planing and milling. In other words, you need to take care not to create a ribbed or irregular surface. You should also remember that this is a fairly brittle sort of wood which threatens to crumble at the edges. Fastening, finish, and treatment

There are a number of points for attention when fastening western red cedar. Note: This is a wood sort which splits easily, but it can be nailed quite simply. To that end use only stainless steel because the substances of the wood react to metals, and that can cause corrosion and ugly streaks.

For the finish it is good to know that paints or stains will not cause any problems if the wood has dried properly. A finish with an opaque paint or a non-transparent agent is also quite easy, although a treatment in accordance with procedure C1 is recommended in order to avoid blueing. Western red cedar is often left untreated with outdoor applications. The wood then has a silky gloss and ages naturally into a charming silver-coloured surface. Wood which faces north is likely to be susceptible to stains and algae growth. The wood also darkens quickly in areas with severe air pollution and a finish with C2 is recommended. If you want to avoid stains, cleaning the planks with diluted bleach (150ml/l water) will effectively reduce stains. The most efficient way to brush the planks is physically with a brush, using diluted bleach in the initial phase. In the second phase you should scrub the wood surface again thoroughly, but this time only with pure water. Although this cleaning process might not remove stains fully, it does nevertheless reduce the stains on the wall. In certain cases it is possible that the treatment may turn the wood a lighter shade. It is advisable to test the treatment first on a less visible section of the cladding before you treat the entire wall.

Source: houtinfobois.be

Other specialists have their say

Denderwood NV (B)

Furnishing & wooden walls and UPM composite solutions from Denderwood NV

Denderwood, an importer and processor of tropical hardwood, offers a high end range of wall claddings in exotic wood. In profiles of the types click plank, plank with sparrow beak, or steel cladding, the Belgian firm can also offer ‘tailored’ stock products, a range of its raw planed planks (false open-ended double or triple, gradient slats, abbreviated profiles). The invisible fastening systems which can be used for horizontal or vertical cladding are also part of the company’s entire range. The main wood sorts are afrormosia, doussie, iroko, ipe, meranti, merbau, padauk, etc. Denderwood is also the exclusive dealer for the BENELUX for UPM products in composite (terraces, clusters, claddings). ProFi cladding is available in stock in various colours.

La San Marco Profili

Decking, with its very natural effect, is ever more popular for both floors and wall cladding, and offers designers and furnishers outstanding solutions for indoors and outdoors walls, for an elegant finish in the most exclusive areas. La San Marco Profili provides everything you need to install even the most complex installation solutions. From screws to clips and jacks, as well as for creating the “full wood” effect, where the clips are concealed. Both oil and aluminium joists are available on request. La San Marco Profili provides all the products required to treat and maintain your floor, such as San Marco oil, always required before installation, and the restoring detergent, which keeps the material as good as new. Furthermore, the company adds to its already wide offer some special materials such as Duro - not just for flooring but also for the ventilated walls - up to the new SMarc Bamboo composite: ultra-resistant and eco-friendly, because 30% made with recycled material. SMarc Bamboo is the brand new product of La San Marco Profili ideal for outdoors: it is a composite made up of 60% Bamboo fiber, 30% of recycled material and 10% of additives. It is a product very resistant to climatic variations, temperature and stains and it is not subject to major color variations. SMarc Bamboo is supplied in two decorations: Walnut, which can be used laying the classic nonslip side at sight or the more refined side with saw cut effect, and Teak, that can be used by laying the side with the modern squared grooves at sight or the particular side with a rustic effect. If you like the appeal of real wood cladding, but do not want to have to deal with all the maintenance concerns and issues, then this product it is the best solution.

Outdoor Wood Concepts®

What are the differences between composite and wood cladding? Various materials are suitable for creating a sleek look with cladding. Wood and composite are the most common. Appearance is one important difference. Wood is a natural material, and even boards from the same type of tree may vary in colour. The grain's warm, lively character is another asset. Composite, on the other hand, is synthetic, with barely any colour variation. Wood cladding is available in several standard widths (90-140-190 mm) and a range of lengths. The fasteners can be visible or hidden. Composite has a fixed length and width and is sold in various colours. The cleaning process is similar for both materials. Simply allow soft soap to soak in, then scrub the cladding with a stiff brush until it sparkles. There are also special cleaning products available for wood or composite. Demand for engineered wood cladding has risen sharply. This wood has undergone thermal treatment, reducing the moisture content. Bear in mind that mould can still grow on the surface. It is advisable to apply a hydrophobic coating and ensure sufficient ventilation if you install it.

Woodface® by Outdoor Wood Concepts®

Product-Proof

In Japan they have used a special technique (Shou Sugi Ban | Yakisugi) for centuries to make wood more durable. Since the 18th century, they have literally burnt a native tree, the cryptomeria japonica (Japanese cypress). This tree then serves as durable wall cladding, which protects the typically wooden houses in Japan from both wildfires and the weather. Wall cladding in burnt wood is much coveted. The wood sorts which you mainly encounter are douglas and larch and sometimes even oak. Some thermally treated wood sorts are also suitable, and it is also possible, for instance, with thermowood or accoya or simply with recycled wood. The five main benefits of burnt wood for wall cladding are: its durability, it is flame-retardant, it is waterproof, it counters insects, and it also counters moss and mould. Visit www.flamewood.be for more information, references, and examples.

Recently, at the request of the architect and contractor (Revo bvba), Product-Proof was able to burn a small section into the wall cladding (house number).