Rain resistance of façades with façade details: A summary of three field and laboratory studies

Olsson, Lars E.

doi:10.1177/1744259117713265

Cited by 19 publications

(24 citation statements)

References 12 publications

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“…Cracks regularly exist at the interface between brick and mortar which can act as preferential flow path for moisture into masonry (Olsson, 2018). A fracture flow model is needed to predict moisture distribution and transport in masonry wall with cracks (Michel and Pease, 2018;Roels et al, 2003).…”

Section: Resultsmentioning

confidence: 99%

Masonry brick–cement mortar interface resistance to water transport determined with neutron radiography and numerical modeling

Zhou

Desmarais

Vontobel

et al. 2020

Journal of Building Physics

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Masonry is one of the most common building envelope systems in the world, providing an excellent water protection solution against rain. Water transport in masonry walls composed of bricks and mortar joints can be strongly affected by the nature of the interface between brick and mortar. In this study, two-dimensional water uptake experiments and numerical simulations are performed to study the effect of interface resistance on moisture transport in masonry samples with horizontal and vertical interfaces. Neutron radiography is used to document the time- and space-resolved moisture content distribution in different masonry samples. In the simulation of moisture transport, an interface resistance models the imperfect contact between brick and mortar. A good agreement between measured and simulated moisture content distribution is observed for different masonry samples. Moisture transport in masonry could be strongly affected by the interface resistance, when interface is in proximity to moisture source. The orientation, horizontal or vertical, of the interface between brick and mortar does not have an influence on the value of the interface resistance. However, the interface resistance depends on the capillary pressure at the interface. In the range of capillary moisture transport, a lower capillary pressure at the interface will lead to a larger interface resistance.

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Section: Resultsmentioning

confidence: 99%

Masonry brick–cement mortar interface resistance to water transport determined with neutron radiography and numerical modeling

Zhou

Desmarais

Vontobel

et al. 2020

Journal of Building Physics

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“…Complementary laboratory studies have been carried out to study how the water droplets enter different types of holes and slits and how different conditions such as pressure difference, the shape of the opening, surface material and dams affect the leakage. (Olsson 2018a, Olsson 2018b.…”

Section: Methods Used To Investigate Moisture Condition In Swedish Womentioning

confidence: 99%

Moisture Safety of Wooden Buildings – Design, Construction and Operation

Mjörnell

Olsson

2019

sace

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During the last decade, building in wood has increased, mainly due to environmental awareness andtargets to decrease the carbon footprint originated from the production of building materials. Newtechnologies such as CLT (cross laminated timber) have accelerated the construction of multi-storywooden buildings. The CLT structure has been used both for housing and offices. Due to the extensivesize of the buildings and relatively fast assembly of the buildings, weather protection has not alwaysbeen used. It is commonly known that building materials sensitive to moisture need to be protectedagainst high moisture conditions and water during construction. If this is not done, there is an increasedrisk of microbial growth which can result in health problems for future users of the building, extensivecosts for the remediation and exchange of materials, but also lack of trust in the construction industry.There are disagreements between the building industry and researchers how sensitive wooden buildingsare to exposure to high moisture levels and water during storage at sites and construction. Based onresults from several research projects studying moisture conditions both in the laboratory and in thefield, recommendations for procurement, storage and handling of wood during construction to assuremoisture safety are suggested in this paper.

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“…The latest research in Sweden confirms the statements in ASHRAE Standard 160, which state that façades are normally not completely rainproof (ASHRAE, 2016) and should be considered in moisture calculations (Olsson, 2017b). In addition, there is no reliable theoretical risk analysis tool to assess the moisture resistance of new façade solutions and of renovation solutions (Bednar & Hagentoft, 2015).…”

Section: Introductionmentioning

confidence: 92%

New algorithm for water leakages flow through rain screen deficiencies

Olsson¹,

Hagentoft²

2018

Healthy, Intelligent and Resilient Buildings and Urban Environments

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There is a need of more knowledge about the mechanisms of water leakage through façades exposed to driving rain to make reliable risk analyses. Therefore, we have studied it in more detail and the outcome include inter alia a new algorithm. The algorithm is developed for calculation of water leakages through rain screen deficiencies. The algorithm is based on empirical values from many measurements according to standardized test method and validation. Even though the leakage process is very complicated, simple correlations have been shown. The leakages flow rate through deficiencies are mainly limited by the runoff rate and the catch area above the hole and around the hole with dam. Apart from wind pressure as a driving force, the inlet of the holes is often on a higher level than the outlet at the rear of the façade, which creates significant hydrostatic pressure, which can be elevated by impoundment at the obstacle. This is the main reasons to comprehensive water leakages through façades without any wind pressure (pressure equalized façades). If precise information about defects data is not available, there are extensive measurements supporting the following assumption-a realistic leakage flow for a small or invisible spot leakage at a façade detail is presumed to be 0.5 to 2% of the runoff rate per meter of façade width. If there are multiple penetrations or obvious defects in the façade design in combination with the dams, a significantly higher proportion of the runoff flow can leak in.

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Rain resistance of façades with façade details: A summary of three field and laboratory studies

Cited by 19 publications

References 12 publications

Masonry brick–cement mortar interface resistance to water transport determined with neutron radiography and numerical modeling

Masonry brick–cement mortar interface resistance to water transport determined with neutron radiography and numerical modeling

Moisture Safety of Wooden Buildings – Design, Construction and Operation

New algorithm for water leakages flow through rain screen deficiencies

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