| 1. |
- Asphaug, Silje Kathrin, et al.
(author)
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Moisture Control Strategies of Habitable Basements in Cold Climates
- 2020
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In: Building and Environment. - : Elsevier BV. - 0360-1323. ; 169
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Journal article (peer-reviewed)abstract
- In many countries with a cold climate, basements are used as dwellings. This presents a major challenge concerning moisture safety design. Climate change is expected to increase the risk of moisture-related damage in basements owing to increasing amounts of stormwater, annual precipitation, and annual temperatures. This study examines the primary moisture control strategies for habitable basements in western cold climate countries by identifying the main differences and similarities in national building recommendations for new buildings. Using Norwegian design guides as a baseline, we identified ten key challenges and compared them with four other cold climate countries’ recommendations given by experts in the field of building physics (building science). The results showed that other countries’ recommendations differ from those of Norway in various key challenges. However, similar but varying recommendations pertaining to ground surface slopes, drainage layers, drainage pipes, capillary breaking layers in floors, avoiding thermal bridges, airtightness, and ventilation were noted. The key differences pertained to the exterior damp proofing of walls, use and position of dimpled membranes and vapour barriers, and use of permeable thermal insulation. The outcome is that countries emphasise the ten key challenges differently. Although the recommendations have many similarities, the weighting (or prioritizing) distinguishes the five countries’ moisture control strategies.
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| 2. |
- Gullbrekken, Lars, et al.
(author)
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Wind pressure coefficients for roof ventilation purposes
- 2018
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In: Journal of Wind Engineering and Industrial Aerodynamics. - : Elsevier BV. - 0167-6105. ; 175, s. 144-152
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Journal article (peer-reviewed)abstract
- Wind pressure coefficients (c p ) are important inputs for analytical calculations of wind load. The aim of this research is to investigate wind pressure coefficients on a test house located in Norway in order to pave the way for improved analysis of wind-driven roofing ventilation. The large-scale test measurements show that the wind pressure coefficient along the eaves of the house varies with different wind approach angles. Assuming wind-driven air flow through the air cavity beneath the roofing, an average Δc p ¯ value of 0.7 is derived for practical engineering purposes. The results from the study are applicable for single or two-storey houses with pitched roofs at different roof angles.
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| 3. |
- Johansson, Pär, 1986, et al.
(author)
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Interior Insulation Retrofit of a Brick Wall Using Vacuum Insulation Panels: Design of a Laboratory Study to Determine the Hygrothermal Effect on Existing Structure and Wooden Beam Ends
- 2013
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In: 12th International Conference on Thermal Performance of the Exterior Envelopes of Whole Buildings, Clearwater, United States, 1-5 December 2013.
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Conference paper (peer-reviewed)abstract
- The increasing demand on energy-efficient buildings requires energy retrofitting measures in the existing building stock. Conventional thermal insulation materials, such as mineral wool and expanded polystyrene (EPS), demand a thick layer of insulation to reach the energy targets. Vacuum insulation panels (VIPs) are a novel thermal insulation component with 5-10 times lower thermal conductivity than the conventional insulation materials, depending on the VIP ageing state. The thermal transmittance of the building envelope can thereby be substantially reduced using a limited additional insulation thickness. Previous research has shown that interior energy retrofitting of exterior walls may increase the moisture content of the walls and increases the risk of freeze-thaw damages at the surface. This study analyzes the hygrothermal consequences on a 250 mm (9.8 in.) thick brick wall retrofitted with 20 mm (0.8 in.) interior VIP (glued directly on the plastered brick wall). Hygrothermal simulations in WUFI 2D are used to study the hygrothermal effects by different material properties and boundary conditions. Apart from the material properties, the amount of driving rain available at the surface is the most important influential parameter in the simulations. The conclusions from this study are used to plan a measurement study in a climate simulator where driving rain and solar radiation will be simulated.
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| 4. |
- Johansson, Pär, 1986, et al.
(author)
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Interior insulation retrofit of a historical brick wall using vacuum insulation panels: Hygrothermal numerical simulations and laboratory investigations
- 2014
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In: Building and Environment. - : Elsevier BV. - 0360-1323. ; 79, s. 31-45
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Journal article (peer-reviewed)abstract
- Old listed buildings need to be retrofitted to reduce the energy use for heating. The possible thickness of the insulation layer is limited by the existing construction. Vacuum insulation panels (VIPs) require less thickness than conventional insulation materials to reach the same thermal resistance. Therefore, it could be more appropriate to use VIPs than conventional insulation materials when retrofitting the building envelope of listed buildings. The aim of this study is to investigate the hygrothermal performance of a brick wall with wooden beam ends after it was insulated on the interior with VIPs. One- and two-dimensional hygrothermal numerical simulations were used to design a laboratory study in a large-scale building envelope climate simulator. The wall was exposed to driving rain on the exterior surface and a temperature gradient. The relative humidity in the wall increased substantially when exposed to driving rain. The moisture content in the wooden beams also increased. There was no significant difference between the relative humidity in the wooden beam ends for the cases with and without VIPs. However, it was found that the reduced temperature in the brick after the VIPs were added led to a higher relative humidity in the wooden beams. It was also clear that when VIPs were added to the interior, the drying capacity to that side of the wall was substantially reduced. Finally, calculations of the U-value showed a large potential to reduce the energy use using VIPs on the interior of brick walls.
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| 5. |
- Johansson, Pär, 1986, et al.
(author)
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Retrofitting a brick wall using vacuum insulation panels: measured hygrothermal effect on the existing structure
- 2014
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In: Proceedings of the 10th Nordic Symposium on Building Physics, June 15-19, 2014, Lund, Sweden.
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Conference paper (peer-reviewed)abstract
- Old listed buildings need to be retrofitted to reduce the energy use for heating. Vacuum insulation panels (VIPs) require less thickness than conventional insulation materials to reach the same thermal resistance. The aim of this paper is to investigate the hygrothermal performance of a brick wall with wooden beam ends after it was insulated on the interior with VIPs. The paper presents the first part of a laboratory study where a brick wall was built in the laboratory and exposed to simulated driving rain. Different measurement techniques of the relative humidity in the construction have been used. The relative humidity in the wall increased substantially when exposed to driving rain. The moisture content in the wooden beams also increased. However, it has not been possible to fully determine the influence by the added insulation layer. It is clear that the drying capacity to the interior side is substantially reduced. These investigations are ongoing and will be reported in future publications.
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