Fuktförhållande i uteluftsventilerade krypgrunder: Mätningar och åtgärder för ett småhus på Gotland
2018 (Swedish)Independent thesis Basic level (university diploma), 10 credits / 15 HE credits
Student thesis
Abstract [en]
The aim of this degree project was to investigate the actual moisture conditions of an outdoor air-ventilated crawlspace which forms the foundation for an old one-family house on Gotland in Sweden. The purpose was further to investigate correlated problems and the possible cause. Measurements have been made to evaluate a possible method to reduce and prevent adverse moist conditions in the foundation. The air temperature and relative humidity inside the crawlspace as well as outdoors was measured for the one-family house on Gotland during a four-week period. Through the first two weeks of measurements (period one) the ground in the crawlspace was free from any cover, but during the last two weeks a diffusion barrier (a plastic foil) was used to prevent evaporation from the ground (period two). Previous measurements (climate data) from Bromma in Stockholm was used as a basis for general complementary reference calculations regarding crawl spaces in order to make the conclusions more reliable. Moreover, to investigate the specific moisture conditions on Gotland an interview with Anticimex have been made. The measurement results presented a relative humidity that favors microbial growth during both periods in the crawlspace, and no significant differences could be proven between the two periods. The results could not be explained by a high evaporation from the ground. No clear difference regarding moisture conditions could be proven by comparing Gotland and the reference calculations in Bromma, and therefore no specific moisture condition on Gotland could be proven. This conclusion was also confirmed by Anticimex. Calculations showed that the relative humidity in the crawlspace was almost never below 75%. The conclusion of this project shows that the moisture conditions in the outdoor air-ventilated crawlspace results in a high risk of microbial growth. This can further result in decay which can decrease the strength of the construction but the human health can also be negative affected. Due to a high relative humidity during the year even a small change in the crawlspace climate results in a significant change regarding moisture conditions. Regarding the outdoor air-ventilated crawlspace on Gotland the high relative humidity can be explained by thermal inertia in the ground, which according to reference calculation results in a high relative humidity. The outdoor air-ventilated crawlspace is categorized as a high-risk construction by many articles and organizations, including this study. Therefore, to ensure a good environment in the crawlspace, regular check-ups should be made to alert the moisture problem in time. A Sorption dehumidifier is considered the best/a good way to prevent and treat the moisture conditions in the crawl ground.
Place, publisher, year, edition, pages
2018. , p. 61
Keywords [sv]
Krypgrund, Uteluftsventilerad krypgrund, fuktförhållande, Gotland, relativ luftfuktighet, fuktproblematik, Burgsvik, åtgärdsförslag, mikrobiell påväxt
National Category
Engineering and Technology Civil Engineering Building Technologies
Identifiers
URN: urn:nbn:se:mdh:diva-40143OAI: oai:DiVA.org:mdh-40143DiVA, id: diva2:1229445
Subject / course
Building Engineering
Presentation
2018-05-31, U2-145, Mälardalens Högskola, Västerås, 22:27 (English)
Supervisors
Examiners
2018-07-032018-06-292018-07-03Bibliographically approved