Façade cladding in thermally modified Ayous

Installing timber cladding or siding

In this episode of Gadero TV, Henk Jan uses thermally modified Ayous as cladding for a façade. This thermo-wood, with a triple banded profile, is highly durable thanks to the special steam treatment. And this means your thermally modified cladding will last you for much longer than regular timber siding. In addition to Ayous, Gadero also carries other types of timber suitable for façade cladding. Have a look at our full range of cladding and siding materials.

One major advantage of these triple banded profile boards is that they are suitable for both horizontal and vertical installation. Horizontal installation is used in this video, but if you prefer a vertical lay-out, then make sure to account for ventilation. Air wants to move vertically, so your battens have to allow for this. Use either ventilation battens with their small open arches, or a double layer of battens and counter-battens if you are using regular timber laths. This double layer is formed by installing a layer of horizontal battens on top of a vertical layer of counter-battens.

Installing façade battens and counter-battens

For a horizontal cladding layout, the wooden battens have to be oriented vertically. The rear battens for the siding have small arches to allow for ventilation along the wall and boards. It is important to affix the battens with the arches facing the wall.

Affix the counter-battens and/or battens to the façade using stainless steel screws installed around every 30 centimetres. There’s no need to pre-drill - in fact, pre-drilling may harm the join of the battens to the walls, and impact their load-bearing strength.

We recommend an interspace of around 40 centimetres between the battens, while keeping in mind how many battens you need. Measure the distance of the outer battens centre-to-centre, and check by what number this distance has to be divided to arrive at an interspace of around 40 centimetres. The video uses 41 centimetres centre-to-centre. We recommend the use of a template, which will save time and effort that would otherwise be spent on measuring the distance between battens and counter-battens.

Installing banded profile boards horizontally

Its treatment makes thermally modified timber quite brittle. As such, we recommend pre-drilling these boards before nailing them down onto the battens and counter-battens. When installing the triple banded boards, it is important to have the tongue pointing down, and the groove or rebate facing up.

The bottom of the lowest cladding board must always be sawed off at a 60-degree angle to improve drainage away from the façade. A table or mitre saw lets you easily saw your boards to size and at the correct angle.

It is important that the first board is absolutely level. To that end, a long spirit level is recommended. Observe about 2 millimetres of interspace between the ends. Hammer the nails down into the thick part of the boards. Round-headed nails are used in the video. You should make sure that the heads of these nails float on top of the boards - they should not bite into the wood.

With the first board in place, it is time to move onto the rest. Slide the tongues into the grooves from the top. However, the boards must not be wedged together too tightly - so use a round head nail as a spacer between the boards. This will ensure there is just enough room for the boards to expand. Once the boards have been nailed down, the spacer can be removed.

Make sure the nails are well-aligned by holding a long spirit level along the screws. If the line is level, move on to pre-drilling the boards, with a series of well-aligned nails now guaranteed. The centre of each board can be skipped.

Cladding the tip

Once you’re ready to clad the tip of the roof, there won’t be enough purchase on the battens. In that case, we recommend adding two more battens going diagonally towards the tip to create enough purchase for the nails going through the remaining boards. By using arched ventilation laths, ventilation along the rear is still possible.

To calculate the angle of the boards, use a t-bevel square. Align it with the line of the next board, and swing the rule to match the line of the roof. Mark down the line on the board, and saw off the excess.

If you’re having difficulty matching the number of boards to the remaining space, then simply raise the preceding boards by several millimetres. Alternatively, saw one final board in half along the length.

Corner trim

There are several ways to finish the corners, for example using mitre cut boards sawn lengthwise. The corner trim profile demonstrated in the video has to have its tongues and grooves removed, after which the board must be sawn in half lengthwise to create two narrow battens in the same timber as the façade. These must then be installed along the corner of the siding. Make sure the battens are not installed too closely together to allow them to expand and contract. The corner trim battens must always be affixed to the battening instead of to the actual cladding.

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