4 Geotech (GEO)

A general rule in LCA is that heavier materials equal a larger climate impact. Since the foundation of a building typically consists of reinforced concrete, decisions made by GEO can significantly impact the LCA calculations. Therefore, it is important to communicate any changes in the foundations to MAT to ensure that they avoid being surprised by a large additional climate impact too late in the project. MAT should also make themselves available to GEO to assist in their decision making if, for example, they wish to compare two different solutions. An example of this could be whether it is better to use a high strength concrete and less reinforcement or a low strength concrete but with a lot more reinforcement. Even if based on preliminary estimations, conducting an early-stage variation study can be beneficial in determining which option offers the lower environmental impact. MAT should be ready to assist GEO by identifying the lowest impact solutions or at the very least provide GEO with the tools and knowledge required to do it themselves.

Table 4.1 below describes the information needed to model the ground slab and mat/slab foundations in an LCA. Note that the information does not necessarily need to be delivered in this format, but at the very least in a way that enables MAT to easily convert the data. Naturally, all the required information will not be available for LCA calculations in the early design stages, in which case educated assumptions are fine.

Table 4.1 Overview of information necessary to model ground slabs and slab foundations in an LCA.

Table 4.2, Table 4.3 and Table 4.4 describe the information needed to model the strip, point, and pile foundations in an LCA. Compared to the ground slab and slab foundations, BR18 is fairly loose about how to model the remaining foundations in an LCA, so the units in the below tables should only be considered a suggestion. What matters is that the total quantities are documented in a way that is transparent and easy to understand for each foundation type. Naturally, all the required information will not be available for LCA calculations in the early design stages, in which case educated assumptions are fine.

Table 4.2 Overview of information necessary to model strip foundations in an LCA (suggestion).

Table 4.3 Overview of necessary information to model point foundations in an LCA (suggestion).

Table 4.4 Overview of necessary information to model pile foundations in an LCA (suggestion).