Using Raw Earth Construction Systems on Contemporary Buildings: Reflections on Sustainability and Thermal Efficiency

Bruno Marques,Helena Corvacho,Luís Baptista,Manuel Correia Guedes,Humberto Varum,Hussein Kazem,Abdul Salam K. Darwish,Marta Szabo

doi:10.1051/rees/2021041

Abstract

Although the existence of building energy efficiency policies for several years, studies show that up to 74% of the participant consider their house uncomfortable. European policies favored construction solutions focused on insulating materials rather than other solutions which traditionally were used and proved to be effective. Construction system that uses earth as construction material showed for centuries that it can offer high levels of thermal comfort in a passive way, with a highly sustainable and quasi-neutral environmental impact. With this paper, a study on the thermal performance of three contemporany rammed earth buildings is presented. The aim is to analyze thermal comfort over a critical period of time. It is expected that earth construction proves to be a good choice, creating a sustainable and better integration with the local environment, with almost zero energy incorporation, promoting the local work craftmen and with a construction range price below the common construction systems.

Highlights

It is estimated at European level that up to 97% require partial or total intervention to improve their energy performance by 2050 [1].In 2012, Portugal presented a building refurbishment production of only 8%, compared to an European average of 26% in the total construction sector, estimated that almost 1 million buildings were already in need of renewal works (Euro-construct, FIEC and AECOPS) [2].In this context, Portugal is presented as one of the countries were the buildings are less prepared to ensure the housing thermal comfort
Throughout centuries, vernacular architecture, in which earth-based constructions were of wide application in southern European countries, has evolved in order to achieve those goals, using the material’s thermal inertia and the building passive strategies
As shown above, spaces that were directly exposed to the sun presented harsh uncomfortable conditions, like in the situation recorded in the outside hotel porch, on the kindergarten patio, on the office entrance or even in the office area of the architectural building with big glazing windows, many times registering temperatures outside the comfort conditions, even with the use of air conditioning in this last case

Summary

Introduction

It is estimated at European level that up to 97% (i.e. all buildings built before 2010) require partial or total intervention to improve their energy performance by 2050 [1]. Given the context and constraints previously exposed, this study goal is to access the current suitability of earth as a building material in different climate conditions, starting from a previous research that has been carried out about this subject, making use of the information already produced, seeking to validate it in a more comprehensive way. To this end, it is proposed the comparison between three buildings with different functions (an office building, a kindergarten and a rural hotel), two of which are located in the same village, Serpa, and another in Odemira, with somewhat different climate conditions. It is expected to show the possible adaptation and suitability of this kind of construction material, with all its advantages, in order to achieve more sustainable and thermal efficient dwellings with low environmental impact

Case study

Economic and environmental components

Economic component

Findings

Environmental component