Materials & Constructions

Overview

Materials are the basic building blocks of all opaque constructions: they define thermal conductivity, density and specific heat capacity of a building material. Constructions combine materials into layered assemblies, which are then assigned to the surfaces of the building model via building components, see Assigning Constructions. The general operation of the database dialogs is described in the Database Concept.

Material database

Access via Databases > Materials… (dialog “Material database”).

Properties

Field	Unit	Meaning
Name	-	multilingual display name
Category	-	building material category for classification and filtering
Conductivity	W/mK	thermal conductivity λ
Density	kg/m3	bulk density ρ
Spec. heat capacity	J/kgK	specific heat capacity c
Manufacturer, Data source, Notes	-	metadata (group “Metadata”)

Categories

The category list comprises 13 values (displayed with English keywords): Coating, Plaster, Bricks, NaturalStones, Cementitious (cement-bound materials), Insulations, BuildingBoards, Woodbased, NaturalMaterials, Soils, CladdingSystems, Foils, Miscellaneous.

Construction database

Access via Databases > Constructions… (dialog “Construction database”). The table lists constructions with name and usage type; the editing area (“Construction editor”) shows the layer assembly, preview and U-value.

Usage of the construction

The field Usage of the construction classifies the assembly for filtering in selection dialogs: outside wall, ground-coupled outside wall, interior component, basement ceiling, ground-coupled base plate, intermediate floor, sloped roof, flat roof (selection list with English labels, e.g. “Outside wall construction”). The usage type also determines the labeling of the two construction sides in the preview, e.g. Inside (A) / Outside (B) for wall constructions or Floor (A) / Ceiling (B) resp. Ground (B) for ceiling and floor assemblies; without a usage type the sides are labeled neutrally as (A) and (B) in the preview. Independent of this, in the layer table the rows Side A (top) and Side B (bottom) always mark the two construction sides.

Material layers

The group Material layers contains the field Number of layers and the layer table with the columns:

Column	Meaning
Material	material selection per layer; a click opens the material database in selection mode (“<select material>” for an empty layer)
Width [cm]	layer thickness; entries below 1 mm are rejected (“The layer widths must be greater than 1 mm. Smaller layers are to be neglected, they have no influence on the thermal storage mass!“)
ρ [kg/m³], cₜ [J/kgK], λ [W/mK]	properties from the selected material (display only)

The layers are ordered from Side A to Side B. When assigning to a surface, the building component assignment defines which side is inside or outside, see Assigning Constructions.

Live U-value

The U-value is recalculated immediately with every change of the layer assembly:

$$U = \frac{1}{R_{si} + \sum_i \dfrac{d_i}{\lambda_i} + R_{se}}$$

with the fixed surface heat transfer resistances $R_{si} = 0{,}13$ m²K/W (inside) and $R_{se} = 0{,}04$ m²K/W (outside). If a layer lacks a material or a layer thickness or thermal conductivity is invalid, no U-value is shown.

Flipping construction layers

The button Flip construction layers reverses the order of all layers (Side A and Side B swap). This is useful, for example, when an imported assembly was defined from outside to inside instead of from inside to outside. For built-in constructions the button is disabled.

Related topics

• Database Concept
• Assigning Constructions
• Construction Check
• Construction Calculation Model