Monitored conditions in wooden wall plates in relation to mold and wood decaying fungi

In historic masonry buildings, wood can be embedded in the walls as storey partition beams, or as supportive wall plates. Half-timbered masonry constructions, or wooden frames, e.g. combined with internal insulation, are other examples of wooden elements. Wood decaying fungi can cause serious damage to wood, which may lose mass and strength, ultimately yielding the risk of collapse. In addition, some fungal species may even be hazardous for occupants. All wood decaying fungi depend on favorable moisture and temperature conditions, although the threshold conditions may vary with various fungal species and types, and state of the wood. To predict the risk of occurrence of wood rot, several models have been developed, however most of these are based on a limited number of experiments, or very specific cases. For these reasons, the applicability of the models to other scenarios (fungal species, wood species) may not be appropriate. Furthermore, another failure mode for wood and moisture, is mold growth, which is initiated at lower moisture levels. An indication of risk of mold growth would indicate problems or risks before the initiation of wood rot. Mold growth does not deteriorate the wood, but is usually equally undesired due to health concerns of occupants. For this reason, there might be places where some mold growth would be acceptable, e.g. embedded beam ends if there is no transfer of air from the moldy area to the indoor air. Therefore, risk of rot could be important. The paper investigates models for mass loss due to wood decay and mold growth based on exposure time to favorable hygrothermal conditions. The investigation is based on inspection of wood samples (wall plates) from a full-scale experimental setup of masonry with embedded wood and monitored conditions, to which the prediction models will be applied. Monitored hygrothermal conditions were implemented in mold and wood decay models, and samples were removed from the test setup. The implemented models yielded high mold index and mass loss, whereas neither mold nor decay was observed in the physical samples. Results indicate that the implemented models, in these cases appear to overestimate the risks of mold and rot in the supportive lath behind the insulation

Klimadata til fugtsimuleringer:referenceår

​Denne rapport omhandler udarbejdelse af et referenceår til anvendelse ved varme- og fugtsimuleringer (hygrotermiske simuleringer). Referenceåret er udarbejdet på baggrund af historiske data for perioden 2001-2019 for Sjælsmark, suppleret med nedbørs data fra Holbæk flyveplads, Hillerød SØ, Store Hareskov og Gørløse for perioden 2001-2010

Hygrothermal assessment of north facing, cold attic spaces under the eaves with varying single sided passive ventilation strategies and infiltration scenarios, in a cool, temperate climate

Relative humidity and temperature were measured in cold attic spaces under the eaves with diffusion-open roofing underlay to investigate different ventilation strategies, the influence of infiltration, and exterior insulated roofing underlay. The project was carried out as a full-scale experimental setup in the cool, temperate climate in Lyngby, Denmark. The objective was to test if the best practice recommendations concerning design of the cold attic space will prevent damaging moisture levels in the attics. Measurements do however indicate that complying with recommendations will not ensure satisfactory moisture levels in the attic spaces. A comparison of the passive ventilation strategies in combination with varying infiltration rates, for attic spaces fitted with diffusion-open roofing underlay, indicate that attic ventilation increases moisture levels. The exterior insulation of the attic space improved the hygrothermal performance

BUILD RAPPORT 2023:11 Klimadata til fugtsimuleringer Referenceår

Dette projekt omhandler udarbejdelse af et referenceår til anvendelse ved varme- og fugtsimuleringer (hygrotermiske simuleringer). Referenceåret er udarbejdet på baggrund af historiske data for perioden 2001-20019 for Sjælsmark. Det er hensigten at referenceåret kan anvendes af projekterende og udførende til at gennemføre fugtsimuleringer og bedømme konstruktioner ud fra danske klimadata. Rapport beskrivelse: Bygningsreglementet foreskriver, at bygninger skal konstrueres og udføres så fugtskader undgås fx skimmelvækst. Bygningers konstruktioner påvirkes af fugt fra udeklimaet og indefra af bygningens brug. En måde til at dokumentere, at konstruktioner er projekteret uden risiko for fugtskader, er ved at udføre en simulering af varme- og fugtforholdene i konstruktioner. I Danmark findes der ikke et simuleringsprogram, som skal anvendes til simuleringer, men der anvendes forskellige programmer fx WUFI® Pro og DELPHIN. Disse programmer har ikke danske klimadata, og derfor anvendes nærliggende klimadata fra fx Lund, Sverige eller Bremerhaven, Tyskland. Denne rapport omhandler udarbejdelse af et referenceår til anvendelse ved varme- og fugtsimuleringer (hygrotermiske simuleringer). Referenceåret er udarbejdet på baggrund af historiske data for perioden 2001-2019 for Sjælsmark, suppleret med nedbørs data fra Holbæk flyveplads, Hillerød SØ, Store Hareskov og Gørløse for perioden 2001-2010. Rapporten er udformet så den dokumenterer grundlaget for referenceåret. Det er hensigten, at referenceåret kan anvendes af projekterende og udførende til at gennemføre fugtsimuleringer og bedømme konstruktioner ud fra danske klimadata. Rapporten er udarbejdet af post.doc Nickolaj Feldt Jensen, adjunkt Tessa Kvist Hansen og seniorforsker Martin Morelli, fra Institut for Byggeri, By og Miljø og adjunkt Anne Marie Svane og professor Rasmus Waagepetersen fra Institut for Matematiske Fag. Projektet er muliggjort med økonomisk støtte fra Aase og Ejnar Danielsens Fond. Vi takker for støtten, der har muliggjort udarbejdelse af et referenceår til fugtsimuleringer. Dette supplerende datasæt indeholder følgende: - Rådata fra DMI (2001-2019), i Excel format. - Ny dansk fugt referenceår for Sjælsmark (samt 4 stk. andre variationer af referenceåret som blev undersøgt i dette projekt). Fugt referenceår findes i WUFI (.txt), Delphin (.c6b) og Excel (.xlsx) format. - Analyser af ny dansk fugt referenceår (mod 4 stk variationer af referenceåret), i Excel format. - WUFI simuleringsmodeller (1D) - Delphin simuleringsmodeller (1D og 2D) - Simuleringsresultater (WUFI og Delphin), i Excel format. - Teoretisk risiko vurdering af skimmelsvampevækst i simulerede konstruktioner, udført med den finske VTT skimmel model. (Excel format) - Build rapport 2023:11 Klimadata til fugtsimuleringer Referenceå

Hygrothermal Analysis of Retrofitted Buildings in the Campus of Lund University

As climate change have become generally accepted as a potential problem, reducing the greenhouse gas emissions and global energy demand has become an important research topic. This have led to an increased interest towards the retrofitting of the existing building stock, including cultural protected buildings. Due to the cultural protection, carrying out major alteration such as exterior wall retrofits are often not possible, leaving interior retrofitting as the only option. Previous studies have however shown that interior retrofitting poses great risks with respect the hygrothermal performance. This study focused on assessing the long term performance of various energy retrofitting measures for the exterior wall and roof constructions with respect to energy- and moisture performance, window replacement was not included. Carried out for two protected buildings in the campus of Lund University, and the adaptability of the retrofitted measures towards the future climate conditions, simulated until year 2100. The economic- and environmental feasibility of the retrofitting measures was furthermore determined through LCC and LCA. Results showed the smart vapour retarder assemblies would outperform both the capillary active as well as the traditional assemblies using PE-foil, with respect to the hygrothermal performance. However, the water repellent coating showed to be vital for any of the wall assemblies to problem free. A potential reduction of the heating demand by 20-30% was shown for the retrofitted walls, while only 5% for the retrofitted roof constructions. The retrofitting measures were shown to be economic infeasible, while the wall measures were shown to be environmental feasible.Hygrothermal Analysis of Retrofitted Buildings in the Campus of Lund University Studying the long-term performance of applying retrofitting measures to two cultural protected school buildings with respect to moisture and energy. Long-term moisture safety and a heating demand reduction of up to 20-30% was achieved. To carry out a retrofit on cultural protected buildings is often a risky task. The protection often contains restrictions which may prevent the use of the safer and more effective methods. Moisture problems are especially likely to occur when interior insulation is used to retrofit existing building parts. The interior insulation will change the movement of heat and moisture passing through the building parts resulting in a moisture build-up. Despite the risks associated with a building retrofit, there has in recent years been a growing interest to do so. Partly due an increased awareness concerning climate change and the potential problem it may bring, but also due to the great energy saving potential the older part of the building stock yield. This includes also retrofitting of cultural protected buildings. It is therefore of utmost importance that more focus is placed on how to solve the problems related to retrofitting using interior insulation methods. Satisfying long-term moisture safety was however achieved using interior insulation when combined with a water repellent coating to retrofit the existing outer walls of two cultural protected school buildings at Lund University in southern Sweden. The best performing solution was a traditional glass wool installation combined with a so called “smart vapour retarder” for airtightness and drying out. A surprising discovery was the importance of the water repellent coating, as it was vital for any solution to succeed. Although the retrofitting measures showed a reduction of 20-30% and 5% respectively for the exterior wall and the roof constructions for the annual heating demand, the measures turned out to be economically infeasible. In contrast to the economic aspect, a retrofit of the exterior walls turned out to be feasible from the environmental aspect. The objective was to assess the long-term performance of various energy retrofitting measures for the exterior wall and roof constructions with respect to the energy and moisture performance. The major focus was placed on retrofitting the exterior wall with interior insulation solutions, while a smaller focus was placed on the roof constructions. The economic and environmental possibility of the retrofitting measures were also accounted for through Life Cycle Cost and Life Cycle Assessment. The study was carried out in six phases: • A literature review phase, reviewing relevant literature and generation ideas. • A project goals phase, defining the project goals, simulation cases and expected results. • A moisture assessment phase, assessing the long-term moisture performance of the wall and roof solutions. • A thermal bridging phase, assessing the thermal bridging effect of the approved solutions. • An energy performance phase, assessing the long-term energy performance of approved solutions using whole-building energy simulations. • Lastly, a feasibility phase, assessing the economic and environmental feasibility of the retrofitting measures