How do I model hybrid constructions such as timber-concrete composites or ventilated facades?

Short Answer

You model hybrid constructions such as timber-concrete composites or ventilated facades cleanly via the component build-up (the cross-section matrix). Add stacked layers with "Add layer"; for layers with materials lying side by side, use "Add section" to split the layer into sections with percentage shares. vyzn then calculates the U-value and the life cycle assessment automatically.

When to Use This

• Timber-concrete composites, e.g. TCC ribbed slabs with timber ribs or beams next to insulation
• Ventilated facades with a substructure, a ventilated air layer and an external cladding
• In general, for inhomogeneous layers in which materials lie side by side

Step-by-Step Instructions

1. Create a component in the catalogue and define the component build-up in the "Cross-section" tab.
2. Build up the assembly as stacked layers using "Add layer" and link a material from the catalogue to each layer, including its layer thickness – for a timber-concrete composite, for example, the concrete and the timber layer on top of each other.
3. For inhomogeneous layers with materials lying side by side (timber ribs or beams next to insulation), use "Add section": split the layer in question into sections and enter the section share in percent for each section. The shares of all sections must add up to 100%.
4. Set the component position via the "Position against" attribute (outside, unheated, heated, ground).
5. For ventilated facades, simply select one of the ready-made "air layer" materials from the catalogue for the ventilated air layer – graded by thickness (e.g. "air layer 5–10 mm", "30–50 mm", "> 100 mm"), each with a suitable equivalent thermal conductivity and no environmental impact (KBOB values set to zero). You do not need to invent anything yourself here.
6. Place the external, ventilated cladding behind the ventilated layer and set the component position accordingly – this way you still capture the cladding for mass and life cycle assessment without distorting the thermal build-up.

Expected Result

• vyzn calculates the U-value automatically from the component position: as the mean of the upper and lower limit of the thermal resistance, weighted by the section shares (the usual limit-value method).
• The life cycle assessment is calculated per cell from the stored KBOB 2022 indicators of the linked material and the section share, and summed up across all cells.
• The thermal transmittance of the air layer results, as with any material, from thickness divided by thermal conductivity.

Common Mistakes

• The section shares of a layer do not add up to 100% – vyzn will point this out to you.
• Inventing your own values for the ventilated air layer instead of selecting the "air layer" material from the catalogue that matches the gap width.
• Not placing the ventilated cladding behind the ventilated layer – this distorts the thermal build-up.

Tip: If you like, we can look at your specific timber-concrete composite or facade build-up together and set up the layers, section shares and component position accordingly.