| 1. |
- Abdul Hamid, Akram, et al.
(författare)
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Hygrothermal assessment of internally added thermal insulation on external brick walls in Swedish multifamily buildings
- 2017
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Ingår i: Building and Environment. - : Elsevier BV. - 0360-1323. ; 123, s. 351-362
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Tidskriftsartikel (refereegranskat)abstract
- Proper and efficient renovation requires understanding the behavior of existing buildings and of different building materials. Analyzing hygrothermal measurements in two case studies, one with and the other without an internally added thermal insulation system, enabled us to identify factors of critical importance for further assessment through simulations, and to validate a hygrothermal simulation model of a solid brick masonry wall, a model used then to assess internally added thermal insulation systems of different types. A mold resistance design (MRD) model shows that, in connection with all internally added thermal insulation systems, the risk of mold growth is appreciable when brought on by solar driven vapor from the exterior. This, if biological material is present in either of two critical areas, those of the boundary between the thermal insulation and either 1) the existing masonry wall, or 2) the exterior surface of an internally added vapor barrier. Furthermore, assessments of corrosion risks are conducted for two critical placements of the bed-joint reinforcement. At a depth of 30 mm from the exterior surface, the corrosion risk was found to be less with use of capillary-active vapor-open systems than when no thermal insulation was employed, other systems increase the corrosion risk. At a depth of 90 mm, all thermal insulation systems increase the corrosion risk. Excluding precipitation uptake eliminates all risks, showing that this is the most crucial factor. Solutions that limit this uptake or increase the drying-out rate should thus be considered beneficial.
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| 2. |
- Abdul Hamid, Akram, et al.
(författare)
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Literature review on renovation of multifamily buildings in temperate climate conditions
- 2018
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Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788. ; 172, s. 414-431
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Forskningsöversikt (refereegranskat)abstract
- In Sweden, approximately 1.4 million dwellings were built 1946–1975. Today, a considerable part of these are in need of renovation for various reasons. Research results, as well as experiences and outcomes from renovation projects could facilitate in performing more efficient renovations. As an aid for further research, this paper aims to compile and review relevant literature that may support in choosing a renovation strategy as well as decisions on renovation measures. The focus of this paper is research on status determinations, renovation strategies and renovation measures. Differences and similarities within these areas are presented through the analysis of 234 relevant references. The results show that renovation of multifamily buildings in temperate climate conditions is widely researched. The included research has a strong energy focus, and while other aspects of renovation are researched as well, they are not as strongly represented. Status determinations are often based on data from national databases that include useful information that could help alleviate decision making in the renovation process. This study suggests that future research should be conducted on the effect of such databases on the renovation process. This study also shows that there are numerous renovation strategies, and while there are both in-depth and broader strategies, these are seldom connected. Finally, there are many references evaluating various effects of the application of renovation measures, but some effects and measures are more widely researched than others. This study lays a strong foundation for further in-depth research on the reviewed articles, reports, and theses.
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| 3. |
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| 4. |
- Bengtsson, Mathilda, et al.
(författare)
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Metoden ByggF-PST : Tillämpning av ByggaF på tillverkning av prefabricerade småhus i trä. Version 1.0
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Metoden som presenteras i detta dokument är en tillämpning av ByggaF påprefabricerad småhustillverkning av hus med träbaserad stomme kallad:”ByggaF för Prefabricerade småhus med trästomme”, hädanefter omnämnd somByggaF-PST. ByggaF-PST är en metod som säkerställer, dokumenterar ochkommunicerar fuktsäkerheten i hela byggprocessen, från planering tillbruksskede. Metoden innebär ett arbetssätt för att uppfylla samhällets krav påfuktsäkerhet och innehåller rutiner och hjälpmedel för alla aktörer, frånsmåhustillverkare, konsulter, materialleverantörer och entreprenörer.
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| 5. |
- Buck, Dietrich, 1990-, et al.
(författare)
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Impregnation of Wood / End Grain Treatment
- 2021
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This research presents the findings of a study conducted by Luleå University of Technology (LTU) and Lund University (LTH) on the effect of edge treatment on the end grain of cross-laminated timber (CLT) elements. The objective of the study was to identify whether edge treatment influences the moisture performance and mould risk of CLT.The investigation was conducted through controlled laboratory studies, utilising standardised procedures. Specifically, the end grain of the CLT specimens was exposed to moisture by placing them in contact with a free water surface for 96 hours. Following this exposure, the specimens were dried under controlled conditions. X-ray computed tomography (CT) scanning was used to estimate the moisture content of the specimens and provide detailed spatial information about the moisture distribution within the wood.To further evaluate the effectiveness of edge treatment, the experimental moisture content assessments were compared to values by WUFI simulations. Additionally, annual data for the simulations were conducted using climate data from three different locations: Lund, Stockholm, and Borlänge. These simulations assessed the theoretical impact of edge treatment on mould risk under different climatic conditions.Results revealed that edge treatment has potential to reduce moisture content and mitigate mould risk in CLT elements. Experimentally assessed moisture content values were consistently lower in edge-treated specimens compared to untreated specimens. The calculations and simulations supported these findings, showing a distinct reduction in moisture accumulation and mould risk in edge-treated CLT elements.This study provides insights into the effect of edge treatment on the moisture performance and mould risk in CLT elements. The findings suggest that implementing appropriate edge treatment techniques can enhance the durability of CLT structures, particularly for worksites in regions where climatic conditions fluctuate over the course of construction. Further research and testing are warranted to explore additional factors influencing the effectiveness of edge treatment in CLT applications.
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| 6. |
- Buck, Dietrich, et al.
(författare)
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Moisture- and mould-resistance : modelling of edge-sealed cross-laminated timber using multi-modal assessment leveraged by X-ray computed tomography
- 2023
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Ingår i: Materials and Design. - 0264-1275. ; 230
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Tidskriftsartikel (refereegranskat)abstract
- Edge-sealing, which involves treating the edges of wood products, improves water resistance. This study investigated the feasibility of edge-sealed cross-laminated timber (CLT) panels to reduce capillary water uptake, thereby resisting mould formation. The water and vapour permeabilities of ten characteristically different single-layer sealant coating systems were systematically determined. X-ray computed tomography (CT) scanning methodology was used to enhance detection of material characteristics beyond the standard coating permeability assessment. Moisture content was observed to change during the specimens’ absorption and desorption depending on the sealant system applied. The results revealed different characteristics of coatings during the water absorption and desorption stages. Findings from this study were used to develop recommendations regarding the water resistance of coating systems, curing time, susceptibility to mould formation, and industrial applicability. Results suggest that edge-sealed CLT could minimise the risk of mould formation, which can occur at worksites with minimal weather protection. The method developed in this study provides a basis to evaluate new coating systems and determine which use case is the best for a particular coating type. This study also incorporates insights from industry to identify future research orientations, which may pave the way for new designs and assessment techniques.
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| 7. |
- Buck, Dietrich, 1990-, et al.
(författare)
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Moisture- and mould-resistance: multi-modal modelling leveraging X-ray tomography in edge-sealed cross-laminated timber
- 2023
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Ingår i: Materials & design. - : Elsevier. - 0264-1275 .- 1873-4197. ; 230
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Tidskriftsartikel (refereegranskat)abstract
- Edge-sealing, which involves treating the edges of wood products, improves water resistance. This study investigated the feasibility of edge-sealed cross-laminated timber (CLT) panels to reduce capillary water uptake, thereby resisting mould formation. The water and vapour permeabilities of ten characteristically different single-layer sealant coating systems were systematically determined. Multi-modal assessment leveraged by computed tomography (CT) scanning methodology was used to enhance detection of material characteristics beyond the standard coating permeability assessment. Moisture content was observed to change during the specimens’ absorption and desorption depending on the sealant system applied. The results revealed different characteristics of coatings during the water absorption and desorption stages. Findings from this study were used to develop recommendations regarding the water resistance of coating systems, curing time, susceptibility to mould formation, and industrial applicability. Results suggest that edge-sealed CLT could minimise the risk of mould formation, which can occur at worksites with minimal weather protection. The method developed in this study provides a basis to evaluate new coating systems and determine which use case is the best for a particular coating type. This study also incorporates insights from industry to identify future research orientations, which may pave the way for new designs and assessment techniques.
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| 8. |
- Claesson, Johan, et al.
(författare)
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Benefits of Investigating the Thermal Component for Moisture Safety in Ventilated Attics
- 2020
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Ingår i: 12th Nordic Symposium on Building Physics (NSB 2020). - : EDP Sciences. - 2555-0403. ; 172
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Konferensbidrag (refereegranskat)abstract
- Cold ventilated attics often have mould problems in Sweden. This is valid both for old and sometimes newly built attics. Increased insulation on the attic floor is assumed to increase the problem. To investigate this, numerical 1D models like WUFI or WUFI+ are typically used. These models give results but the physical processes are not so transparent for the user due to the complex numerical techniques involved and takes a long time to simulate. The problem is mainly related to the temperature in the attic, the ventilation rate and possible of leaks from the living space. All exposed surfaces in the attic will buffer moisture variations. But if this buffering is neglected and the leakage is treated as a constant the moisture content in the attic is only dependent on the ventilation with outside air and the assumed leakage. This would make a pure thermal investigation meaningful. An analytical model for the thermal problem was developed that took into account radiation between the interior surfaces and the different boundary conditions at the outside and inside surfaces. Using this model a parameter study of exterior roofing insulation was done using a moisture transport model that only took into account convection exchange. The results were compared with WUFI Pro and WUFI+ simulations which included the moisture exchange between air and internal surfaces. The comparison showed that the pure thermal model gave, as expected, larger variations in relative humidity, but that the results were qualitatively very similar. This indicates that analytical solutions of thermal problems can be used as a base in qualitative investigations of certain combined heat and moisture problems.
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| 9. |
- Dahlblom, Mats, et al.
(författare)
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Vertical temperature gradients in apartments with hydronic radiator heating
- 2019
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Ingår i: Cold Climate HVAC 2018 : Sustainable Buildings in Cold Climates - Sustainable Buildings in Cold Climates. - Cham : Springer International Publishing. - 9783030006617 - 9783030006624 ; , s. 575-585
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Konferensbidrag (refereegranskat)abstract
- A vertical temperature stratification normally exists in rooms during the heat-ing season in cold climates. An expression of the gradient in apartments heated by hydronic radiator heating systems with exhaust ventilation has ear-lier been developed assuming a dependency of the outdoor temperature. The expression was used by a public real estate owner when re-calculating meas-ured indoor temperature at 2.1 m above floor to 1.2 m above floor represent-ing the occupancy zone and used for individual metering and billing of space heating cost. To validate the suggested expression temperature measurements have been made at four heights in living rooms in apartments built in the 70’s. The heights includes 0.0, 0.1, 1.1 and 1.7 m above floor. The theoreti-cal expression has been compared to the full-scale measurements and in general the expression overestimates the vertical temperature gradient. The measured gradients are generally very low. The thermal comfort in the aspect of vertical temperature gradient is good for the studied period.
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| 10. |
- Hansen, Thor, et al.
(författare)
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Investigation of the Mould Resistance Design (MRD) model for mould growth in attics
- 2020
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Ingår i: 12th Nordic Symposium on Building Physics (NSB 2020). - : EDP Sciences. - 2555-0403. ; 172
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Konferensbidrag (refereegranskat)abstract
- Based on measurements of mould in 17 attics in the north of Sweden, 3 were chosen as a tentative validation of the MRD-model (Mould Resistance Design) for long periods of time (1961-2012). Comparing the measurements and the results from the simulations showed great differences regarding the mould growth depending on the simplifications used in the model. How the leakage was simulated and where the moisture from the leakage was placed in the construction were the most important factors. The study could not validate the MRD model as such, but it was clear that the simulations with relatively small adjustments could give realistic data.
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