Hiil cladding maintenance guide — washed and brushed panels

See also the installation guide

About maintenance in general

Charred wood is generally easy to care for and requires less upkeep than wood that has been only oiled. With proper care and correct maintenance, charred wood remains beautiful for decades.

This guide describes the maintenance of Smoke, Smoke+, Charcoal, Bark, Bark+, Frost, Soot, Snagwood, Autumn Glow and Moss cladding products made from pine and spruce, in the use cases they are suited to.

Read the section that applies to your use case as well as the common finish section.

Maintenance: exterior cladding

Avoid mechanical strain. Washed and brushed surfaces withstand wear better than a char surface, but hard abrasion or impacts can damage them too.

Keep the cladding surface clean. When needed, rinse or gently wipe off leaves, pollen, cobwebs and other dirt. If you rinse the surface, use as little water as possible and make sure water does not get into the structures behind the cladding.

Prevent build-up of organic matter. Make sure that shrubs, grass or tree branches do not collect against the façade.

Wash carefully if necessary. If the surface needs washing, use a mild, pH-neutral detergent and a soft brush. Avoid excessive scrubbing and harsh detergents which can damage the surface. Test the detergent on a small area first.

Mind the structures. Ensure that eaves, trims and flashings direct water away from the façade.

Inspect the cladding regularly and re-oil where needed.

Need for re-treatment

Washed and brushed surfaces change over time outdoors. Untinted surfaces (Smoke and Bark) grey and fade. Patination is an essential part of a clear-oiled product and is not damage. The original tone cannot be restored by oil treatment. Tinted surfaces (Smoke+, Charcoal, Bark+, Frost, Soot, Snagwood, Autumn Glow and Moss) retain their tone longer thanks to the pigment, but they too fade gradually.

Outdoors, the protection provided by the oil weakens gradually. How quickly depends on how much sun, rain and snow the surface receives. The need for maintenance also depends on how much patina you are happy to allow. For this reason we do not give a fixed maintenance interval; instead, we recommend inspecting the façade regularly, especially south- and west-facing walls and areas not sheltered by the eaves.

Maintenance treatment with oil may be due if:

• the tone of a tinted surface has clearly faded, for example faster on sunny walls than elsewhere, and you want to keep the tone close to the original
• the surface has sustained a substantial area of damage

In that case, treat the affected areas as described in “Maintenance treatment”. If in doubt, please contact us.

Maintenance: interior cladding, sauna and wet rooms

Avoid mechanical strain. Washed and brushed surfaces withstand wear better than a char surface, but hard abrasion or impacts can damage them too.

Dust lightly. Use a soft duster, microfibre cloth or lightly damp cloth, or vacuum gently with a brush nozzle. Do not use abrasive cloths or strong detergents.

Prevent standing water. The structure must be able to dry out. Interior cladding rarely needs wiping with a damp cloth.

Wood surfaces in sauna and wet rooms. Washed and brushed surfaces also suit saunas and wet rooms. Even in these spaces, surfaces should be dried after use and good ventilation maintained. Avoid heavy scrubbing when cleaning and use cleaners with as neutral a pH as possible.

Prevent stains from setting. If anything is spilled on the surface, wipe it off carefully and immediately.

Need for re-treatment

Indoors the surface is not exposed to rain and usually not to strong sunlight, so the protection provided by the oil lasts considerably longer than outdoors. In a shady, dry location the tone of the surface usually stays unchanged for a long time. In a sunny location, for example near large windows, UV radiation can gradually lighten the tone of the surface.

Maintenance treatment with oil may be due if:

• the tone of a tinted surface has clearly faded and you want to keep the tone closer to the original
• the surface has sustained a substantial area of damage

In that case, treat the affected areas as described in “Maintenance treatment”. If in doubt, please contact us.

Maintenance treatment

Use the same finish product that the factory originally applied. Hiil products are treated with special linseed oil. The oil shade depends on the surface — order maintenance oil using the product’s surface name. If you are uncertain, ask us for a suitable finish and more detailed instructions.

Always follow the instructions of the finish product. Test the maintenance treatment on a small area in an inconspicuous spot before treating the visible surfaces more widely. Wipe off any excess finish that the surface has not absorbed.

Protect sensitive surfaces from possible oil splashes and drips (paving, floors, plinths, windows, etc.).

Note that in direct sunlight or on a hot day, oils can dry too quickly. The oil then does not have time to soak into the product adequately, and proper protection does not form.

WARNING — risk of spontaneous combustion

WARNING! Many drying natural oils pose a risk of spontaneous combustion.

Rags, sponges and sawdust soaked in oil can ignite spontaneously if left in a pile.

Lay rags and sponges flat to dry one by one outdoors on a hard surface, or submerge them in water — never leave them bundled in a bin.

Repairing surface damage

If damage occurs that breaks the factory-treated surface and exposes fresh, untreated wood, DO NOT repair the damage with a gas torch. Finish products generally do not tolerate fire and may ignite or smoulder.

The damaged spot should be re-oiled with the same product originally used on the surface.

Tips for successful surface treatment

• Check conditions. Temperature +10…+25 °C and low direct sun are ideal. In too high temperatures the oil dries too quickly and does not absorb properly.
• Use the original finish product. Re-treat with the same product that the surface was originally treated with.
• Protect surroundings from possible splashes — paving, floors, plinths, windows.
• Test first on a small, inconspicuous area to confirm the result.
• Apply a thin, even coat and let the oil absorb. Wipe off any excess that the surface has not absorbed.

Re-use and disposal

All Hiil products are designed for long-term use lasting decades. If the products are dismantled for any reason, reuse the timber elsewhere if possible. This way the carbon bound in the product stays bound, the work that went into manufacturing remains useful, and the wood gets a new life.

All Hiil products contain only wood, linseed oil, and possibly a small amount of colour pigment. The finishes used in the products are not classified as hazardous. If you choose to dispose of the product, the timber can be used as an energy source.

Contact

Hiil Oy
info@hiil.fi
https://hiil.fi

Up-to-date contact information is available at hiil.fi.