Benchmarking the Environmental Impact of Green and Traditional Masonry Wall Constructions

In Belgium, the most common approach for nearly Zero Energy Buildings is to comply with the locally modified version of the German Passive House (PH) Standard that requires a very low conductivity of exterior walls. The conventional PH brick constructions are dominated by building materials with high environmental impact including concrete blocks, firebrick and petrochemical insulation materials that produce a great amount of greenhouse gases (GHG). Moreover, there are very few studies that assessed the holistic environmental impact of conventional wall compositions against ecological wall compositions. Therefore, this research compares a traditional Belgian representative wall against a hemp block wall, according to the PH standard. The environmental impact of each wall is quantified through a life cycle assessment. The final results indicate that the hemp wall reinforced with a wood skeleton has a much lower impact on the environment: up to 60% reduction on total primary energy, 72% on climate changes, 93% on eutrophication, 61 % on ozone layer depletion and 74% on acidification. Future work may refine the assessment process. The study provides novel and significant findings that can inform building owners, architects and contractors and encourage them to choose environmentally friendly masonry wall compositions.