Moisture conditions in highly insulated outdoor ventilated crawl spaces in cold climates

Matilainen, Miimu; Kurnitski, Jarek

doi:10.1016/s0378-7788(02)00029-4

Cited by 15 publications

(15 citation statements)

References 5 publications

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“…They have also stressed a limited effect of air change rate on moisture control [1,2]. However, these measures may not be sufficient to keep RH below critical value during critical weather conditions.…”

Section: Discussionmentioning

confidence: 99%

“…For varying temperature and humidity conditions Viitanen et al [18] gives a differential equation for wood (pine and birch): dM dt ¼ 1 7 expðÀ0:68 ln T À 13:9 ln RH þ 0:14W À 0:33SQ þ 66:02Þ (2) where M is the mould growth index, and t is the time calculated in days. The mould growth index illustrates the growth rate.…”

Section: Performance Criteriamentioning

confidence: 99%

“…16). The recommendation of an earlier study [2] to use a 30 cm LWA to prevent high RH seems to be true as with 75% RH set point the heating is switched on only 7% of the time. With a 20 cm LWA cover the heating is on 13% of the time, and with CS and PVC sheet the heating is on roughly 20% of the time.…”

Section: Control Strategymentioning

confidence: 99%

“…A highly insulated crawl space and a low air change rate of about 0.5 ach. For a highly insulated crawl space at least 30 cm LWA or 10 cm expanded polystyrene (EPS) ground cover is needed [2]. Unventilated or warm crawl space without any outdoor air ventilation, which require obviously a very careful insulation work [3,4].…”

Section: Introductionmentioning

confidence: 99%

“…According to earlier studies [1,2,5] a high risk for mould growth can usually be avoided with a sufficient thermal insulation on the ground. However, even in this case, moisture conditions may become problematic if the summer is exceptionally moist and rainy [1,5].…”

Section: Introductionmentioning

confidence: 99%

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03/01957 Moisture conditions and energy consumption in heated crawl spaces in cold climates

2003

Fuel and Energy Abstracts

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A crawl space foundation is widely used in buildings and detached houses in northern countries. The relative humidity (RH) of the air in crawl spaces is the most critical factor of the mould growth in the structures of a crawl space. The objective of the study was to find out whether heating is a feasible alternative for crawl space moisture control with reasonably low energy consumption. The effects of summer heating in an outdoor air-ventilated crawl space with different ground covers and air change rates were simulated in this study. The simulations were carried out for an apartment building and a detached house. The effects of the control strategy, heating capacity, air change rate and ground covers on the energy consumption were studied. Mould growth index was used as performance criteria for acceptable conditions in the crawl space. To assess the sensitivity of the main simulation parameters a differential sensitivity analysis (DSA) was used. In the parametric simulations, the used ground covers were lightweight expanded clay aggregate (LWA), crushed stone (CS) and PVC. The control of heating was based on RH controller with the set point between 70 and 80% and a heater with heat output from 2.5 to 10 W/m 2 of crawl space area. It was shown that a thick layer of LWA prevents mould growth even without heating, but the layer with heating still provides lower RH An alternative method for moisture control is to use a ground cover without thermal insulation and heating of the crawl space. This method proved to be a good alternative to control mould growth. The specific energy consumption for heating of the crawl space was roughly the same order of magnitude in the studied apartment building and detached house. Annual specific energy consumption was generally low, within the range of 1.4-3.6 kWh/m 2 of the crawl space area in most of studied cases. The energy consumption rose considerably when a lower set point value of RH was used, consequently the time when the heating is on was the highest when the set point value was lowest. With heating, it was possible to prevent any mould growth, i.e. to keep mould growth index equal to zero. #

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Section: Discussionmentioning

confidence: 99%

Section: Performance Criteriamentioning

confidence: 99%

Section: Control Strategymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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03/01957 Moisture conditions and energy consumption in heated crawl spaces in cold climates

2003

Fuel and Energy Abstracts

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Klimatische Verhältnisse in Kriechkellern unter gedämmten Holzbodenplatten

Werther

Winter

2009

Bauphysik

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Hochgedämmte Holzbodenplatten über Kriechkellerkonstruktionen als unterer Abschluss eines Gebäudes kamen in den letzten Jahren im Bereich des Wohn‐ und Zweckbaus in Holzbauweise vermehrt zur Anwendung. Fehlende Kenntnis zu den im Kellerbereich herrschenden Mikroklimabedingungen und die sich daraus ergebenden Nutzungsrandbedingungen für Holz und Holzwerkstoffe führten zu unterschiedlichen Konstruktionsformen. Mittels Langzeitmessungen im Feld‐ und Laborversuch wurden Konstruktionsprinzipien entwickelt, die einen dauerhaften Einsatz von Holzbodenplatten über belüfteten Kriechkellern sicherstellen.

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Numerical study of time-dependent hygrothermal conditions in depressurized crawl space

et al. 2018

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Moisture conditions in highly insulated outdoor ventilated crawl spaces in cold climates

Cited by 15 publications

References 5 publications

03/01957 Moisture conditions and energy consumption in heated crawl spaces in cold climates

03/01957 Moisture conditions and energy consumption in heated crawl spaces in cold climates

Klimatische Verhältnisse in Kriechkellern unter gedämmten Holzbodenplatten

Numerical study of time-dependent hygrothermal conditions in depressurized crawl space

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