Current through Register Vol. 35, No. 16, August 27, 2024
Section 14.7.4.14 - RAMMED EARTH SOIL SPECIFICATIONSA. General. The soil shall not contain rock more than one and one-half inch in diameter. The soil shall not contain clay lumps more than one-half inch in diameter. The soil shall be free of all organic matter. The soil shall not contain more than two percent soluble salts.B.Soil compressive strength. Prior to the start of construction, fully-cured rammed earth soil samples shall be tested at an approved testing laboratory for compressive strength. The ultimate compressive strength of all rammed earth soil, stabilized or non-stabilized, shall be a minimum 300 psi. The compressive strength report shall be submitted with the permit application. This report may be waived if the builder provides certification of compliance. The certification must be dated within one year of the date on the application for the building permit. Samples tested shall be representative of soil to be used on the project for which the permit application is submitted.C.Stabilized rammed earth soil. The following shall apply to stabilization of rammed earth soil: Asphalt emulsion may not be used for stabilization of rammed earth soil. Thorough mixing of additives to the soil may be achieved by any method that assures a complete blending to a uniform color and texture. Stabilized soil is suitable soil that contains six percent or more Portland cement by weight or that passes ASTM D1633-00. Samples tested shall be representative of soil to be used on the project for which the permit application is submitted. The compressive strength report shall be submitted with the permit application. Laboratory testing shall indicate rammed earth samples attained a minimum of 200 psi after seven days. If a different soil is provided at any time during construction, it must meet the minimum requirements outlined above, prior to use in the structure.D.Unstabilized rammed earth soil. Unstabilized rammed earth soil is that containing less than six percent Portland cement by weight or that fails to pass ASTM D1633-00. The exterior of such walls shall be protected with approved stucco systems or other method approved by the building official. Refer to 14.7.4.19 NMAC for weather-resistive barrier requirements.E.Amended soil. The following guidelines shall apply when amending soils to attain a qualified soil. Soil shall not contain rock greater than one and one-half inch in diameter. Soil shall not contain clay lumps greater than one-half inch diameter. Soil shall be free of organic matter. Soil shall not contain more than two percent soluble salts. Soils to be mixed shall be sufficiently dry to blend completely to one uniform color and texture. The amended soil shall be tested prior to use as per Subsection B of 14.7.4.14 NMAC.F.Forming systems. The forming system shall be adequate to contain the material under compaction. It shall be properly plumbed and braced to withstand the soil pressures as well as construction activity on and around it.G.Placement of material, compaction and curing.(1) No amount of Portland cement stabilized soil will be mixed that will not be placed in the wall system within 60 minutes of its preparation.(2) Lifts of prepared soil shall be placed in the forms in relatively even layers not to exceed eight inches in depth. Each lift shall then be rammed to full compaction.(3) Optimum moisture content as determined to meet minimum compressive strength shall be maintained for stabilized and unstabilized walls.(4) Work will progress, lift-by-lift, until the work approaches bond beam height.(5) Forms may be stripped immediately after ramming is completed for a section of wall, providing ramming of adjacent sections does not affect the structural integrity of completed walls.(6) Portland cement stabilized walls not in forms shall be lightly spray-cured with water at least five spaced times during daylight hours. This procedure shall continue for at least three days starting from the time that the wall is exposed to the elements. Exception: Rammed earth walls left in forms three or more days shall not require water-spray curing.H.Placement of attachment materials.(1)Nailers: Nailers incorporated into the rammed earth wall shall be installed as follows (Refer to Figure 4 of the earthen building figures supplement); the rammed earth wall shall not be reduced in thickness with back-to-back nailers. To avoid an hourglass configuration in the wall section, nailers on either side of a running wall shall not be opposite each other. Nailers on either side of a running wall shall be separated from each other vertically a distance not less than the rammed earth wall thickness. Nailers shall be placed onto the wall such that the narrow dimension of the nailer is exposed on the race of the wall prior to ramming. Nailers shall be cured and sealed against moisture penetration prior to installation in forms. The nailers shall not extend the full depth of the wall. Box wood nailers are not allowed. (Refer to Figure 11 of the earthen building figures supplement). The nailer shall be no more than two inches by four inches by its length.(2)Channels: Channels may be incorporated into the rammed earth wall as follows (Refer to Figure 2 of the earthen building figures supplement); to avoid an hourglass configuration in the wall section, channels on either side of a running wall shall not be opposite each other. (Refer to Figure 4 of the earthen building figures supplement). Channels shall be no more than two inches by four inches by their length in dimension. Vertical channels shall not be placed closer than two inches to a rammed earth wall finished edge or corner.14.7.4.14 NMAC - Rp, 14.7.4.14 NMAC, 1-28-11, Adopted by New Mexico Register, Volume XXVII, Issue 21, November 15, 2016, eff. 11/15/2016