A Mini-Review on Straw Bale Construction

Abstract

Straw bale building construction is attracting a revived public interest because of its potential for reduced carbon footprint, hygrothermal comfort, and energy savings at an affordable price. The present paper aims to summarize the current knowledge on straw bale construction, using available data from academic, industry, and public agencies sources. The main findings on straw fibers, bales, walls, and buildings are presented. The literature shows a wide variability of results, which reflects the diversity of straw material and of straw construction techniques. It is found that the effective thermal conductivity, density, specific heat, and elastic modulus of straw bales used in construction are in the range 0.033–0.19 W/(m·K), 80–150 kg/m3, 1075–2000 J/(kg·K), and 150–350 kPa respectively. Most straw-based multilayered walls comply with fire resistance regulations, and their U-value and sound reduction index range from 0.11 to 0.28 W/m2 K and 42 to 53 dB respectively, depending on the wall layout. When compared to standard buildings, straw bale buildings do provide yearly reductions in carbon emissions and energy consumption. The reductions often match those obtained after applying energy-saving technologies in standard buildings. The paper ends by discussing the future research needed to foster the dissemination of straw bale construction.

Exploring Low-Carbon Design and Construction Techniques: Lessons from Vernacular Architecture

“…Straw bale [68] Nigeria [69] Africa [70] Middle East [71] Global [72] Britain [73] Portugal [74] New Zealand [75] Italy Cordwood [76] France [77] Poland, Scandinavia, Central Europe, Eastern Canada, and Northern United States [78] Scandinavia, Canada, Northern United States [79] North America, Europe [80] Canada…”

“…It can be exposed or covered by soil or lime stucco. The bale's shape, dimension, and level of compression depended on the baler used, it was found the density of barley straw bales range from 54.6 kg/m 3 to 78.3 kg/m 3 , while oat and wheat straw bales range from 81 kg/m 3 to 106.3 kg/m 3 [71]. Research indicated the thermal conductivity of straw bales is lower than that of concrete, brick, and wood.…”

“…On the other hand, the modern-day straw bale construction often uses bales as insulative infill that does not carry structural load. The outer layers around a straw bale core are made of hardwood, plaster, or cement [71]. structural strength is competitive with concrete and steel structures, with a much lower associated embodied carbon.…”