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Skimmelsvampe danner under deres vækst i bygninger både sporer og flygtige stoffer, der er mistænkt for at give helbredsgener for bygningsbrugere. Ved renovering af skimmelsvamperamte bygninger anbefales det, at al inficeret materiale fjernes eller afrenses. Men somme tiderer dette ikke fysisk eller økonomisk muligt. Forsegling eller indkapsling anvendes ved nogle renoveringer, men metoden har aldrig været testet videnskabeligt. Formålet med projektet var at undersøge om det er muligt at forsegle/indkapsle skimmelsvampevækst i bygningens sværttilgængelige dele af klimaskærmen, således at sporer og flygtige stoffer forbliver på og i de materialer, de er dannet på og ikke trænger ud i indeklimaet, hvor mennesker opholder sig.Gips- og OSB-plader blev opfugtet og de skimmelsvampesporer, der naturligt var i materialerne, fik lov til at gro ud. Frigivelse af sporer, partikler og flygtige organiske stoffer (TVOCer) blev undersøgt under laboratorieforhold i CLIMPAQ opstillinger. Mycometer Air blev anvendt tilsporedetektion og en Lasair II til partikelbestemmelse. Ethanol blev brugt som modelstof for TVOCerne og detekteret med en Innova 1312 gasmonitor. Almindelig Flügger akrylvægmaling, Luxi maling på spraydåse og Protox Forsegler blev testet for deres evner til at indkapsle sporer,partikler og ethanol. Skimmelsvampe danner under deres vækst i bygninger både sporer og flygtige stoffer, der er mistænkt for at give helbredsgener for bygningsbrugere. Ved renovering af skimmelsvamperamte bygninger anbefales det, at al inficeret materiale fjernes eller afrenses. Men somme tiderer dette ikke fysisk eller økonomisk muligt. Forsegling eller indkapsling anvendes ved nogle renoveringer, men metoden har aldrig været testet videnskabeligt. Formålet med projektet var at undersøge om det er muligt at forsegle/indkapsle skimmelsvampevækst i bygningens sværttilgængelige dele af klimaskærmen, således at sporer og flygtige stoffer forbliver på og i de materialer, de er dannet på og ikke trænger ud i indeklimaet, hvor mennesker opholder sig.Gips- og OSB-plader blev opfugtet og de skimmelsvampesporer, der naturligt var i materialerne, fik lov til at gro ud. Frigivelse af sporer, partikler og flygtige organiske stoffer (TVOCer) blev undersøgt under laboratorieforhold i CLIMPAQ opstillinger. Mycometer Air blev anvendt tilsporedetektion og en Lasair II til partikelbestemmelse. Ethanol blev brugt som modelstof for TVOCerne og detekteret med en Innova 1312 gasmonitor. Almindelig Flügger akrylvægmaling, Luxi maling på spraydåse og Protox Forsegler blev testet for deres evner til at indkapsle sporer,partikler og ethanol.

Ved indvendig efterisolering kan man i nogle tilfælde anvende faste isoleringsplader, der klæbes direkte på indersiden af ydervæggen i stedet for en traditionel forsatsvæg med dampspærre. Man bør dog tage de nødvendige forholdsregler til at forebygge skimmelvækst. Dette indebærer, at væggen afrenses grundigt for alt organisk materiale, ikke mindst eventuelle skimmelrester. Mekanisk afrensning er her den mest effektive metode. I øvrigt bliver skimmelvækst hæmmet af klæbemidler med en pH-værdi på mindst 9,5. Det er vigtigt, at underlaget er plant, så der ikke opstår hulrum i klæbemidlet, når isoleringspladerne monteres.

The built environment is estimated to be responsible for nearly 40% of the world’s total energy usage, and 30-40% of the emissions. Approximately 40% of the European building stock was constructed before 1960, and these buildings often have large heat losses through the building envelope and perhaps also thermal comfort issues. A large share of the aforementioned buildings have an exterior appearance worthy of preservation due to their historic or aesthetic values which prevents the use of renovation measures that could compromise these values. In terms of retrofitting the façade walls, external insulation is often prohibited leaving internal insulation as the only remaining option. However, internal thermal retrofitting solid masonry walls is generally regarded as risky since the added insulation causes the existing wall structure to become colder and wetter, which increases the risk of interstitial condensation. In addition, the added insulation reduces vapour diffusion drying to the room side. These factors contribute to elevated moisture levels in the wall structure and an increased risk of moisture induced damage. Consequently, there exists a need for defining robust methodologies for the installation of internal insulation of historic solid masonry walls, which do not cause hazardous fungal growth or other undesirable issues e.g. decay of embedded wooden elements.The purpose of this study was, in a large field experiment, to investigate several either diffusion-open or diffusion-tight insulation systems to determine if it is possible to internally retrofit solid masonry walls without causing hazardous fungal growth. The investigated diffusion-open insulation systems were: polyurethane with calcium silicate channels, monolithic calcium silicate, lightweight autoclaved aerated concrete, and lime-cork based insulating plaster. The diffusion-tight systems were: phenolic resin foam, and traditional mineral wool with a vapour barrier. These systems were examined in combination with exterior hydrophobisation. The field study findings were complemented by calibrated numeric simulations performed to investigate additional parameters and the robustness against changing climate conditions in the future. The field experiment and the laboratory tests also investigated if controlling the immediate surroundings would prevent the occurrence of fungal growth and the risk of fungal growth affecting the indoor climate. Lastly, several mathematical models for prediction of mould growth and wood decay were assessed and compared to on-site microbiological tests.The field study showed high relative humidity levels in the internally insulated solid masonry walls without exterior hydrophobisation in the case of high indoor moisture load during winter. In addition, the diffusion tightness of the insulation was found to be of considerable importance in terms of the hygrothermal performance. Without exterior hydrophobisation the diffusion-open insulation systems were found to perform slightly better than the diffusion-tight systems. However, in the case of test walls with exterior hydrophobisation the diffusion-tight systems performed considerably better. The material and microbiological tests in the field experiment and the laboratory study showed no fungal growth in the interface between the masonry wall and insulation in the case of high alkalinity (pH>12) in the surrounding materials i.e. the internal render and adhesive glue mortar. This suggests that if high alkalinity could be maintained then fungal growth could probably be prevented despite the presence of unacceptably high moisture levels. In systems where the alkalinity declined rapidly it was found to be of considerable importance to ensure that no organic additives or elements were present in the critical locations. Furthermore, diffusion tests with VOCs mimicking Microbial Volatile Organic Compounds produced by fungal growth showed that in the case of growth behind the insulation the VOCs were able to penetrate most of the examined systems and potentially affecting the indoor air quality negatively. The rate of diffusion through the systems was found to be relatively large for the highly water vapour diffusion-open insulation systems, especially in the case of highly volatile VOCs such as acetone or ethanol. The mould growth and wood decay prediction models were found to overestimate the risk, and for the mould growth predictions this was probably due to the high alkalinity and insufficient access to nutrition in the critical locations.

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.

This report comprises a study of material threshold values, failure modes and related failure prediction models to enable an evaluation of adding internal insulation in historic brick buildings. Threshold values and prediction models have been investigated both within literature and through laboratory study, by for instance comparing prediction models to real field results and by testing threshold values in laboratory. The aim of this report is to find threshold values and suitable and reliable prediction models to be included in the decision guidelines and the web tool, which are the final outcomes of the RIBuild project. Failure modes included in the report are mould growth on building materials, rot and wood decay, frost damage and discoloration of facades. ispartof: pages:1-155 status: Published online

This report comprises a study of material threshold values, failure modes and related failureprediction models to enable an evaluation of adding internal insulation in historic brick buildings.Threshold values and prediction models have been investigated both within literature and throughlaboratory study, by for instance comparing prediction models to real field results and by testingthreshold values in laboratory. The aim of this report is to find threshold values and suitable andreliable prediction models to be included in the decision guidelines and the web tool, which are thefinal outcomes of the RIBuild project. Failure modes included in the report are mould growth onbuilding materials, rot and wood decay, frost damage and discoloration of facades.

Ny forskning viser, at det godt kan lade sig gøre at isolere massive ydermure indvendigt uden at opsætte en traditionel dampspærre. Forsøgene peger på, at man både skal håndtere fugt, der kommer udefra og indefra, hvis man skal opnå en god løsning. Indvendig isolering kræver dog stor omhu, hvis man skal undgå skimmel- og fugtskader.

Relative humidity (RH) and temperature were measured in several solid masonry walls with embedded wooden beams, fitted with autoclaved aerated concrete (AAC) thermal insulation on the interior surface and exposed to a cool, temperate climate. The field study was based on the use of a 40‐feet insulated reefer container reconfigured with eight 1 × 2 m holes containing the solid masonry walls. The study investigated the influence of AAC thermal insulation on the interior side with a combination of exterior hydrophobization and a deliberate thermal bridge in front of the embedded wooden wall plate using a material with higher thermal conductivity. Validated HAM simulations were used to investigate the effect of controlling the indoor humidity, and how this would affect the theoretical risk predictions from the damage models. Experimental findings indicate that hydrophobization of solid masonry walls with internal insulation have both positive and negative effects on the moisture balance of the wall, in relation to moisture‐induced damage, and that a deliberate thermal bridge installed in front of the embedded wooden wall plate can reduce the moisture content in the wooden elements. Simulation findings indicate that a combination of exterior hydrophobization and decreased indoor moisture load can reduce the RH to acceptable levels in relation to moisture induced damage at the interface between existing wall and new insulation. No major changes were observed in relation to the risk of frost damage at the exterior surface.