Editing Adobe (section)

==Material properties==
[[File:Djenne great mud mosque.jpg|thumb|The [[Great Mosque of Djenné]], [[Mali]], built in adobe. The struts projecting from the wall serve as decoration, as well as supports for scaffolding during maintenance.]]
[[File:Niger, Agadez (50), house repairs, old town.jpg|thumb|Maintenance of historic architecture in [[Agadez]], [[Niger]], by adding a new layer of mud rendering]]
Adobe walls are load bearing, i.e. they carry their own weight into the foundation rather than by another structure, hence the adobe must have sufficient compressive strength. In the United States, most building codes<ref>{{cite web|url=http://quentinwilson.squarespace.com/storage/adobecode.pdf |title=14.7.4 NMAC |access-date=25 June 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130818200926/http://quentinwilson.squarespace.com/storage/adobecode.pdf |archive-date=18 August 2013 }}</ref> call for a minimum compressive strength of {{cvt|300|lbf/in2|N/mm2|order=flip}} for the adobe block. Adobe construction should be designed so as to avoid lateral structural loads that would cause bending loads. The building codes require the building sustain a {{convert|1|g}} lateral acceleration earthquake load. Such an acceleration will cause lateral loads on the walls, resulting in shear and bending and inducing tensile stresses. To withstand such loads, the codes typically call for a tensile modulus of rupture strength of at least {{cvt|300|lbf/in2|N/mm2|order=flip}} for the finished block.

In addition to being an inexpensive material with a small resource cost, adobe can serve as a significant heat reservoir due to the thermal properties inherent in the massive walls typical in adobe construction. In climates typified by hot days and cool nights, the high thermal mass of adobe mediates the high and low temperatures of the day, moderating the temperature of the living space. The massive walls require a large and relatively long input of heat from the sun ([[radiation]]) and from the surrounding air ([[convection]]) before they warm through to the interior. After the sun sets and the temperature drops, the warm wall will continue to transfer heat to the interior for several hours due to the time-lag effect. Thus, a well-planned adobe wall of the appropriate thickness is very effective at controlling inside temperature through the wide daily fluctuations typical of desert climates, a factor which has contributed to its longevity as a building material.

Thermodynamic material properties have significant variation in the literature. Some experiments suggest that the standard consideration of conductivity is not adequate for this material, as its main thermodynamic property is inertia, and conclude that experimental tests should be performed over a longer period of time than usual – preferably with changing thermal jumps.<ref>{{Cite journal|first1=Aimilios|last1=Michael|first2=Maria|last2=Philokyprou|first3=Stavroula|last3=Thravalou|first4=Ioannis
|last4=Ioannou|year=2016|title=The role of adobes in the thermal performance of vernacular dwellings|url=https://craterre.hypotheses.org/files/2018/07/TERRA-2016_Th-4_Art-071_Michael_corr.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://craterre.hypotheses.org/files/2018/07/TERRA-2016_Th-4_Art-071_Michael_corr.pdf |archive-date=2022-10-09 |url-status=live|journal=Terra Lyon 2016}}</ref> There is an effective [[R-value (insulation)|R-value]] for a north facing {{convert|10|in|cm|adj=on}} wall of R0=10 hr ft<sup>2</sup> °F/Btu,<ref>{{Cite web|url=http://www.greenhomebuilding.com/QandA/adobe/mass.htm|title=Mass and insulation with adobe|access-date=12 December 2019}}</ref> which corresponds to thermal conductivity k=10 in x 1&nbsp;ft/12 in /R0=0.33 Btu/(hr ft °F) or 0.57 W/(m K) in agreement with the thermal conductivity reported from another source.<ref>{{cite book|last1=Chávez-Galán|first1=Jesus|last2=Almanza|first2=Rafael|last3=Rodríguez|first3=Neftali|title=Proceedings of ISES World Congress 2007 (Vol. I – Vol. V) |chapter=Experimental Measurments [sic] of Thermal Properties for Mexican Building Materials to Simulate Thermal Behavior to Save Energy |publisher=Springer|year=2008|isbn=978-3-540-75996-6|pages=496–501|doi=10.1007/978-3-540-75997-3_89}}</ref> To determine the total R-value of a wall, scale R<sub>0</sub> by the thickness of the wall in inches. The thermal resistance of adobe is also stated as an [[R-value (insulation)|R-value]] for a {{convert|10|in|cm|adj=on}} wall R<sub>0</sub>=4.1 hr ft<sup>2</sup> °F/Btu.<ref>{{Cite book|title=2009 New Mexico Energy Conservation Code Residential Applications Manual, v2.0|last=Hagan|first=Dan|publisher=State of New Mexico Energy, Minerals and Natural Resources Department Energy Conservation and Management Division (ECMD)|date=January 2011|pages=9}}</ref> Another source provides the following properties: conductivity 0.30 Btu/(hr ft °F) or 0.52 W/(m K); specific heat capacity 0.24 Btu/(lb °F) or 1 kJ/(kg K) and density {{cvt|106|lb/cuft|kg/m3}},<ref>{{cite web|title=HVAC Systems AE-390|url=http://www.pages.drexel.edu/~act27/AE390/A5/index_files/Page536.htm|publisher=Drexel University|access-date=25 November 2014}}</ref> giving heat capacity 25.4 Btu/(ft<sup>3</sup> °F) or 1700 kJ/(m<sup>3</sup> K). Using the average value of the thermal conductivity as k = 32 Btu/(hr ft °F) or 0.55 W/(m K), the thermal diffusivity is calculated to be {{cvt|0.013|sqft/h|m2/s}}.