Abstract
Hygrothermal performance of soils coupled to buildings is a complicated process. The computational
approach for heat transfer via the ground is well defined (EN-ISO-13370:, 2007) together with
simplified methods (Staszczuk, Radon, & Holm). Though the soil moisture transfer is generally
ignored, it is proven not negligible (Janssen, Carmeliet, & Hens, 2004).
Even though reliable material properties of soils are required to perform realistic hygrothermal
calculations of soils coupled to buildings, such material properties have not been well defined in
hygrothermal calculations tools. Typical building constructions which are greatly influenced by soils
are basements, crawl spaces and slab on grade and reliable hygrothermal performance of such
construction are highly requested; as it is ranked within the top 10 Building America Enclosure
Research Ideas according to Enclosures STC - Residential Energy Efficiency Stakeholder Meeting,
February 29, 2012 – Austin, TX. There exists an extensive amount of measurements on soil properties
in Soil Science though this information must be gathered as well as adapted to be applicable in
Building Science and for hygrothermal simulation purposes.
Soil properties are important when analyzing and designing both new building constructions and
retrofitting measures, where the outer boundary of the buildings enclosure consists of soil materials.
Concerning basement energy retrofits, interior solutions of improving the energy demand has to
cooperate with the existing soil properties and must therefore be designed thereafter. In concerns of
exterior retrofits, the soil material can be replaced, if needed, with a more suitable filling material,
though this approach applies only for basement walls. The soil material beneath the basement floor
can naturally not be replaced hence the soil properties of this part of the buildings enclosure still
must be taken into consideration.
This study is divided into several parts. The intention of the first part is to gather, comprehend and
adapt soil properties from soil science. The obtained information must be applicable for Building
Science related tasks and validated in hygrothermal calculation tools hence the second part of this
study will focus on validation of the implemented soil properties. Basic changes in the software code
may be requested as well. Different basement constructions will be created with a hygrothermal
calculation tool, WUFI, from which simulations will be compared with existing or on-going
measurements.
The final outcome of the study is to enable an evaluation of several soil types in several climate zones
combined with a number of basement assemblies. The study will define which type of soil together
with a certain building construction which is considered most and least reliable in concerns of energy
consumption and moisture safety. Further, what influences different soils will have on the total
energy loss via the ground and if the performance of a different soils can be measured by a
comparison of soil properties solely.