Earth architecture in north of Portugal: case study from vernacular to contemporary

Abstract

This paper refers to earth solutions in Portugal, covering from a synthesis of vernacular examples to a contemporary approach suggested by the author. This approach consists on a non structural earth wall solution, using a conventional steel reinforced concrete structure in order to permit earth walls to be used both in single-storey as in multi-storey buildings and be accepted in fulfilling contemporary demands of structural and functional performance. A thermal zoning strategy with two distinct inertia areas was proposed to the north littoral of Portugal. An indirect heat gain heavyweight compartment - made with earth walls and steel reinforced concrete structure and slabs - was positioned on the south zone and conceived to lodge the resting zones of a house: bedrooms, bathroom and living room. The north compartment, made with lightweight materials - plaster board and fibre-cement panel walls and timber structure - was destined for the working areas: studying, cooking and eating. This zoning strategy allowed a good compromise between construction costs (mainly embodied energy on the present analysis) and operative costs (mainly thermal comfort on the present analysis) comparing to a conventional monozone layout solution using the Portuguese conventional hollow brick and steel reinforced concrete constructive system. Both solutions were tested on real scale test cells, and the results are presented. It was verified that it is possible to implement a solution with earth walls in order to achieve a good functional performance, similar and even better, in some aspects, to conventional hollow brick solutions, even in a temperate climate, also associated with a significantly lower environmental cost related with the construction phase.