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Due to the heritage value of historical buildings, the external facade can often not be modified. Therefore, heritage buildings require interior insulation when undergoing an energy renovation. However, interior retrofitting drastically changes the hygrothermal behaviour of a wall and can potentially cause moisture-related problems. Besides an interior retrofit, a changing climate might also trigger some of these damage mechanisms since parameters such as temperature and precipitation will change over time. It is proven that hygrothermal models can provide relevant insights into the risk of deterioration associated with these damage phenomena. Heat, Air and Moisture (HAM) tools are commercially available but rarely used in the building industry to study deterioration risks. Translating research into practical tools and guidelines is a challenge across the whole field of building renovation. This paper aims to tackle that challenge, by means of creating a hygrothermal risk assessment tool based on 48,384 HAM-simulations for the climate of Brussels, Belgium. Seven different performance criteria are addressed and discussed: freeze-thaw damage, mould growth, wood rot, corrosion, moisture accumulation, salt efflorescence and bio-colonisation. Subsequent to a sensitivity analysis, the study further investigates how these results can be translated into practice, providing building practitioners the most suitable insights and recommendations.

Since the external facades of our architectural heritage are protected and not allowed to be modified, our patrimony will have to be insulated from the inside during the renovation wave. However, interior retrofitting drastically changes the hygrothermal behaviour of a wall. These new conditions can induce different moisture-related problems such as freeze-thaw damage, mould growth, wood decay, condensation and corrosion. Whether or not damage will occur is dependent on many different parameters. Heat Air and Moisture simulations (HAM) can provide relevant insights for interior retrofitting practice but are rarely addressed. By creating a methodology to convey the results and insights from hygrothermal simulations to the building industry, decision-making for building practitioners will improve regarding risk management when interior retrofitting.

Cuba is known for its rich cultural heritage, consisting of monumental and domestic architecture. Several sites are recognized UNESCO world heritage, e.g. the historic centre of Old Havana and Camagüey. However, major parts of the built environment are in a poor state due to moisture-related problems. These problems lead to degradation processes in building components, such as biological growth, fungal decay, and salt efflorescence. Further, it remains uncertain how climate change will impact the degradation risks. Conservation strategies accounting for climate change are highly needed, but remain absent. Therefore, we assessed the impact of climate change on degradation processes in Cuban building envelopes. This paper presents the results of hygrothermal simulations on wall assemblies in Havana, Camagüey, Santiago De Cuba, and La Fe. A range of parameter variations are included for three scenarios of projected greenhouse gas emissions. Wall assemblies with different characteristics, e.g. location, material properties, exposure coefficients etc., behave all in a different way. Therefore, the range of the climate change impact for individual degradation risks is quite wide. The biological and fungal growth in building components is likely to increase due to rising temperatures, and high moisture loads. The change in salt crystallization cycles depends on the type of salt (hydrated or non-hydrated salt). Moreover, the critical wall orientation, i.e. the wall orientation with the highest degradation risks, remains constant over the 21st century. Yet, the critical orientation is not the same for different damage risks. To conclude, climate change has an important impact on the degradation risks in historical buildings in Cuba. Henceforth, the climate change impact can be included in practical conservation strategies.

Architecture in Cuba has a rich and colourful history, where the colours are literally seen in the Old Havana streets. Several sites are declared World Heritage by UNESCO, such as the historical centre of Camagüey due to its peculiar urban form. Recent studies have shown that 30% of the world heritage sites in Cuba were constructed using earthly materials. Unfortunately, this number is rapidly decreasing where nowadays, only 10% is still standing and half of them show risks for biological deterioration, fungal growth, or salt crystallization. These degradation phenomena are at the root of the high collapsing rates and should be prevented at all costs. HAM-simulations have an added value in the research for renovation and restoration strategies. However, these simulations require a high accuracy for input variables. It is important to make correct assumptions for applied construction materials. For bricks, aspects as granularity, clay or sand content, compaction and firing techniques vary greatly in Cuba and have a major impact on the brick pore structures and consequently on its hygrothermal properties. In an early stage of a renovation project, exact building information is usually not provided, and in most cases a full material characterization is absent. This study investigates the potential to fill in the missing values of incomplete material data with a clustering approach for the Cuban climate. This methodology determines equivalently behaving bricks based on the impact of their properties on the hygrothermal behaviour regarding the mould growth, wood rot and salt crystallization.

Cuba, and more specifically Havana, is known throughout the world for its rich architectural heritage. The 214 ha centre of Havana, consisting of primarily housing, is inscribed as UNESCO world heritage. Nevertheless, is Cuba suffering from a major housing crisis. 70% of the built environment requires major repairs and 7% of the housing context has been declared uninhabitable. In order to tackle the degradation problem, while simultaneously protecting the historical heritage, there is an urgent need for tools and practical guidelines. These should provide insight into the approach to conserving Havana’s heritage and the risks that could entail. The reasons for this deterioration and damage include different moisture-related problems due to the hot and humid climate of Cuba: mould growth, salt efflorescence and the rotting of wooden beam heads embedded in the masonry of the façade. Heat Air Moisture (HAM) models have been found a valuable tool to assess the risk on deterioration and premature failure of building components due to moisture-related problems. This paper demonstrates the process from hygrothermal simulation to practical guideline. The study focuses on the potential of the practical applicability of simulation output from Delphin 6, to produce practical schemes using classification trees. These results will improve decision-making for building practitioners and clarify which parameters have the biggest impact on the risks of deterioration, thus providing insights into the conservation of heritage buildings of Havana, Cuba.