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Robust Internal Thermal Insulation of Historic Buildings

Periodic Reporting for period 3 - RIBuild (Robust Internal Thermal Insulation of Historic Buildings)

Reporting period: 2018-01-01 to 2020-06-30

Energy consumption in historic buildings must be reduced for EU to become climate-neutral in 2050; they account for more than a third of the total energy consumption of buildings. The potential for energy savings in historic buildings related to internal insulation of external walls is 15-20 % and it will improve the indoor climate as draft close to the external walls will be reduced. However, authorities, building owners and building professionals need guidelines to handle internal thermal insulation in historic buildings in an effective and secure way, maintaining their architectural and cultural heritage.

RIBuild investigates how and under what conditions internal thermal insulation can be employed. Research activities include on-site case studies, simulations, development of decision tools and laboratory measurements of materials. Based on that, guidelines for setting the goal for renovation of a historic building , for determining whether a building is suitable for internal insulation or not, for a standardised simulation and testing methodology, with a catalogue of possible solutions depending on the construction type, climate etc., and for evaluating the energy saving potential and the environment impact, are developed.

The guidelines at www.ribuild.eu are targeted at authorities, building owners, building professionals and researchers. Information and guidance are given at different levels of detail, from videos explaining the basic concepts, risks and benefits using internal insulation, via short descriptions and checklists, to detailed guidelines and RIBuild research reports. The website also links to RIBuild datasets and scientific publications.

RIBuild developed two decision tools: For the building owner or building professional to get a list of feasible internal insulation solutions, targeted for the specific location, orientation and design of his building (Insulation Calculator Tool, ICT), and for detailed analysis of the environmental impact and cost/benefit, designed for specialists. Both are based on a probabilistic approach further developed in the project, to handle the uncertainties related to changing the design of a building, of which the information about existing building materials is limited. The ICT is a beta-version, not fully functional in its present state.

RIBuild is an important step to increase the understanding of internal insulation and the potential benefits, not only among building professionals, but also among building owners not being familiar with this way of improving the energy performance of a building. By making this complex field more understandable it might increase the number of buildings becoming internally insulated (in a correct way) helping EU to reach the goal of a carbon free society.
D1.1: Screening on the existing building stock and examples of renovation of historic buildings carried out. D1.2: Literature survey on existing insulation materials and methods for application in historic buildings, and decision tools for implementation of internal insulation in historic buildings.

D2.1: The decisiveness of material properties e.g. depends on which failure mode is considered. D2.1 presents common simulation tools available for hygrothermal simulation, a compilation of material properties for historic building materials and internal insulation materials, and methods to determine material properties. D2.2: 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. D2.3: Present knowledge on water repellent agents.

D3.1: Three laboratory test stands involving internally insulated wall samples with embedded joist end constructions. The tests aim to derive general conclusions about the performance of different insulation systems. D3.2 is based on a number of case studies involving internal insulation and gives general recommendations for when a building is feasible for internal insulation. Both deliverables offer valuable data sets for the validation of software tools.

The effectiveness and efficiency of the hygrothermal simulation tool used in RIBuild was improved and different approaches on how to perform probabilistic assessment more efficiently were analysed (D4.1). Different models have been studied to reduce the computational complexity. The potential of using neural network to predict the hygrothermal behavior of an internally insulated wall was analysed (D4.2). D4.4: A critical analysis of the probabilistic approach and the conceptual aspects of the methodology used for probabilistic assessment and design for indoor climate in buildings.

D5.1: Desk-top analyses on the potential energy savings in historic buildings when considering internal facade insulation. A methodology and software tool developed within RIBuild for probabilistic assessment of the environmental impact of internal insulation solutions, further developed to cover Life Cycle Cost in D5.2.

D6.1: A web tool presenting feasible insulation systems based on user input (location, orientation, wall design) and based on pre-calculated examples; online calculation of a specific building is too time-consuming even with the work done in WP4. D6.5: Design of the simulations. D6.2: Written guidelines. D6.3: Design and concept of RIBuild website. D6.4: Test of website, web tool and guidelines.

WP7: Project website (D7.8) press releases (D7.9 D7.10) procedure for evaluation research results (D7.1) reports on mapping of networks (D7.2) and formation of partnerships (D7.3) information kit (D7.4) seminars (D7.5 D7.6) journal and conference papers (D7.7) dissemination and exploitation plan (D7.11 D7.12).

Three meetings were held with the External Expert Advisory Board, giving valuable input to the contents and goals of the project. RIBuild was present at international conferences, gave radio interviews, etc. More than 50 communication activities took place, 65 scientific papers were published and 25 more to come.
Application of internal insulation in existing buildings is limited, primarily related to lack of knowledge. Systematic gathering of data on material, component and building level took place in RIBuild, including studies on the effect of impregnating the façade. Combined with development of probabilistic modelling, it should be possible to broaden the results achieved at material, component and building level to other materials, constructions and locations.

A methodology for probabilistic assessment of hygrothermal simulation developed in RIBuild makes it possible to take into regard uncertainties related to properties of historic building materials when simulating an internal insulated wall. WP4 shows that it is possible to reduce the computing time markedly making a probabilistic assessment much more feasible than today.

A methodology for probabilistic life cycle assessment was developed; present methods based on a deterministic approach are not sufficient to correctly assess variations in energy use and environmental impact.

A beta-version of an insulation calculator tool using the approach from WP4 has been developed. Due to challenges concerning e.g. the automation of the simulations and the lack of sufficient reliable models for relevant failure modes, the tool is not to be used as a stand-alone tool.