Settlement densification is a key measure against increasing land consumption. Prefabricated timber construction is ideally suited due to its structural and operational advantages. Nonetheless, late involvement of experts leads to late certainties in costs and construction. Based on a publicly available timber construction system, the LoftConcept research project developed further improvements: Parametric constructions and (semi-)automated calculation of performance indicators. Parametric components and details were modelled in Rhinoceros/Grasshopper, stored in a database (Simultan) and assigned to an architectural model either automatically by preselecting standard constructions or manually, also in Simultan. This approach enables calculations to be performed directly on the parameterized digital twin within the same software environment. The thermal transmittance (U-value) of homogeneous components is calculated in accordance with standards based on a target value. Simplified assumptions were made to calculate U-values of inhomogeneous components and regarding harmful condensate only verification-free components were used. To compute non-renewable primary energy consumption, acidification potential and total global warming potential of each component and the whole building, a mass balance was created in Simultan and aggregated with material parameters. The calculation of sound insulation descriptors at the building component level is based on partially standardized empirical models. The presented methodology integrates these calculation approaches with the framework of the EN ISO 12354, enabling the assessment of acoustic performance at building level. The procedure was validated using data from established building component databases. Modelling, component assignment, and performance calculations were validated using an example building representing a two-storey vertical extension segment.