Plannable, modern, durable: WPC facades as a material choice in architecture

Architects often demand contradictory things from a facade: the organic texture of wood, paired with minimal upkeep. WPC facades resolve this conflict technically — the polymer matrix provides weather resistance without chemical after-treatment, while the design integrity of the concept is preserved over the service life. As a Swiss specialist dealer we make documentation, samples and specialist advice for architects and project planners available on a project-by-project basis.

What do architects need to know about the material system?

WPC combines wood fibres, polymers and additives in the extrusion process to form a homogeneous profile. Unlike wood, which reacts to fluctuations in moisture by swelling and shrinking, the composite behaves in a dimensionally stable way; co-extruded profiles additionally carry a closed top layer as a protective and colour-bearing coat. The relevant characteristic values are not generic but product-specific — they are stated in the datasheet of the respective profile and belong in every specification.

Documented system values, using Eco Face Keilspund as the example

Value	Eco Face Keilspund
Profile	194 × 27 mm, hollow-chamber profile
Covering width	185 mm
Lengths	standard 3.6 m · special lengths up to 5.2 m
Weight	14.15 kg/m²
Requirement	5.4 battens per m²
Surface	smooth sanded · 7 colour shades
Installation	vertical or horizontal · rear-ventilated curtain-wall facade (VHF)
Fixing	tongue-and-groove joint, concealed with stainless-steel mounting clips — flat surface with a closed, opaque joint

Narrower profiles in the range — such as the Eco Face Splin CoEx — emphasise the vertical; we provide their technical values with the product-specific datasheet. The complete range is shown in the WPC facades category.

Wooden Tec WPC Facades Eco Face Keilspund

Weatherproof WPC façade in a traditional tongue-and-groove design – splinter-free, colourfast and maintenance-free. Invisible clip installation for quick and elegant finishing.

Sale From 61,- / m²

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How does the building envelope work as a system?

In Swiss practice, the rear-ventilated curtain-wall facade is the standard for high-quality building envelopes; within it, the WPC profile forms the outer, visible layer. The ventilation cavity is a functional building component: warm, moist air from inside the building must be discharged via inlet openings at the base and outlet openings at the roof termination — the air gap is usually planned at 20–40 mm and must not be closed off during execution.

Thermal expansion. WPC moves with temperature. The panels are therefore installed in a floating manner: clips and clamps do not fix rigidly, and expansion joints at edges, butt joints and connections follow the installation specifications of the respective system. A rigid abutment at a window reveal leads to deformation when it warms up in summer — joint planning therefore belongs in the detailing phase, not on the building site.

How do you design with covering width, surface and light?

The facade is the face of the building. Wider profiles — such as the Keilspund with a covering width of 185 mm — structure large facade areas calmly and generously; narrower profiles emphasise verticality and make taller volumes appear slimmer. Smooth sanded surfaces create precise shadow edges when the sun is low and underline clear lines; brushed surfaces scatter the light more softly. With seven colour shades — from anthracite and stone grey through to brown and mixed tones — the envelope can be matched to its surroundings and material context; the effect is best assessed on a sample in daylight: order the sample box.

How does WPC compare with other facade materials?

Criterion	Wood (natural)	Fibre cement	WPC
Material character	hygroactive, moves	mineral, brittle	dimensionally stable composite
Maintenance	recurring coats of paint	cleaning	cleaning
Joint appearance over the years	variable	very stable	very stable
UV behaviour	greys when untreated	very stable	designed to be colour-stable, product-dependent
Detail complexity	high (swelling allowance)	high (cutting)	medium (clip and clamp system)

The choice of material remains a question of project context: where total costs over the service life and a stable appearance are what counts — on facades that are difficult to access, for instance — WPC plays to its strengths.

What has to be clarified regarding fire protection in Switzerland?

In Switzerland, facade claddings are subject to the VKF fire protection regulations; what is decisive is the classification in accordance with EN 13501-1 — and specifically for the profile used within the actual system build-up, not for «WPC» as a material. For the building application, the following therefore applies: use the classification and verifications set out in the documentation of the respective profile, and request object-specific system verifications early — we provide the available documents and clarify outstanding verifications for your project via the contact form.

Why does the timing of a renovation now also matter for tax?

With the yes to the abolition of the imputed rental value (national vote of 28 September 2025), the taxation of owner-occupied residential property changes fundamentally. The Federal Council has set the entry into force of the system change for 1 January 2029: until the end of 2028, owners of owner-occupied properties can continue to deduct maintenance and renovation costs — the invoice date is what counts. From 2029 these deductions no longer apply to owner-occupiers, together with the federal deduction for energy-efficiency renovations; for rented properties the maintenance deduction remains in place.

For advising private building owners this means: a value-preserving facade renovation that is due in any case is also of interest for tax purposes in the window up to the end of 2028 — and no longer after that. The distinction between value-preserving and value-enhancing work as well as cantonal differences still have to be observed; this article does not replace tax advice — the building owner clarifies the details with their tax adviser or the cantonal tax office.

What does the life-cycle assessment look like?

The assessment does not end at the factory gate: over the service life, WPC does away with the recurring coats of paint and the associated coating substances that can be washed out of weathered timber facades. For certifications (LEED, DGNB, Minergie-ECO), the recycled content and emission values must be checked against the product documentation. Our article Sustainable facade systems – how do you make a well-founded decision? offers a detailed decision aid.

Which details make the difference in execution?

Building corners. With a material that moves, exact mitres at the joint can hardly be kept free of cracks in the long term. The system solves this with its own aluminium profiles — internal corner, external corner, termination and butt-joint profile, powder-coated in the respective profile colour — which draw a clean line and absorb the movement of the panels.

Window connections. Connection profiles must lead water away from the facade skin without interrupting the rear ventilation — joint planning follows the system specifications.

Base area. The base carries the highest load from splash water; in practice the cladding ends at a sufficient distance above ground level, and the substructure is executed to be corrosion-resistant.

Which documents are available for the specification?

For privacy screen and facade systems, tender texts (in Swiss tenders: Ausschreibungstexte) are available; we compile samples, datasheets and project-specific details before the specification stage — handle and check first, then put out to tender. Our article WPC in the project: planning terrace, privacy screen and facade examines the project and cost perspective across all three product lines.