Challenges when retrofitting multi-storey buildings with interior thermal insulation

Tommy Riviere Odgaard

Research output: Book/ReportPh.D. thesisResearch

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Abstract

Today, approximately 25 % of the apartments in the Danish multi-storey stock of more than two stories are found in buildings with masonry facades erected in the period 1850-1930. Of these apartments, 71 % are situated in Copenhagen, the Danish capital. The building traditions and norms in force during the period entail that these buildings share similar characteristics, including solid masonry walls and embedded wooden components. The energy use and indoor climate was not in focus during construction, wherefore the current occupants cannot expect modern levels of thermal comfort and the section include a considerable energy saving potential. It is evident that thermal comfort and energy use can be improved by increasing the thermal resistance of the façade. With focus on the masonry part of the total façade area, this can be achieved with thermal insulation applied to the interior or exterior surface. While application to the exterior surface is the best solution from a building physics point of view, the retention of the exterior façade expression is often a desire from the owner or a preservation requirement, leaving application to the interior surface as the only possibility. The buildings from the period have been investigated to determine the degree of shared characteristics within the building segment, showing similar building techniques with consistent thin spandrels under the windows and a low share of available interior surface area for the application of insulation. There were performed thermal simulations of characteristic façade sections in 3-dimensional models, finding that insulation of the spandrel can achieve up to 40 % of the maximum possible reduction achievable from reducing the thermal transmittance by retrofitting the masonry with interior insulation. The influence on the hygrothermal conditions when applying interior thermal insulation to solid masonry walls have been investigated experimentally in a case study and by comparative analyses of results from two field experiments. The case study was 2 rooms in a dormitory with a normal indoor moisture load, situated at an urban location. The study showed how retrofitting the interior surface of a solid masonry spandrel with a diffusion open thermal insulation system changed the hygrothermal balance in the wall, resulting in a colder and wetter wall with similar conditions throughout the wall. Evaluation of the case study, based on measurements and on-site investigations, showed no calculated or observed risks of moisture-induced damage. The field experiments were designed and constructed with an extensive measurement program, exposed to a high indoor moisture load and located in a rural area. The measurements were used for comparative analyses, to investigate the difference in hygrothermal performance of different interior thermal insulation systems, applied to the entire masonry surface or with some variations within the systems. The comparative analyses were based on the measured relative humidity, temperature and on mathematical damage models able to take exposure time into consideration. The damage models were used to compare the calculated risks of moisture-induced damage in the different systems. The results of the comparative analyses with the boundary conditions of the field experiments showed: > Application of a thermal insulation system depending on a tight vapour barrier or a diffusion open thermal insulation system resulted in an increase in calculated mould germination and growth on the masonry surface behind the insulation. > Application of a thermal insulation system depending on a tight vapour barrier resulted in an increase in calculated irreversible wooden decay in the wooden beam (floor joist), compared to other insulation systems and an un-insulated wall. > Hydrophobizing the exterior masonry surface with a hydrophobic façade treatment had an overall positive effect on the hygrothermal conditions, and can be further improved by replacing a part of the moisture-open insulation with autoclaved aerated concrete.
Original languageEnglish
PublisherTechnical University of Denmark, Department of Civil Engineering
Number of pages312
ISBN (Print)9788778774811
Publication statusPublished - 2019
SeriesB Y G D T U. Rapport
NumberR-386
ISSN1601-2917

Cite this

Odgaard, T. R. (2019). Challenges when retrofitting multi-storey buildings with interior thermal insulation. Technical University of Denmark, Department of Civil Engineering. B Y G D T U. Rapport, No. R-386
Odgaard, Tommy Riviere. / Challenges when retrofitting multi-storey buildings with interior thermal insulation. Technical University of Denmark, Department of Civil Engineering, 2019. 312 p. (B Y G D T U. Rapport; No. R-386).
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title = "Challenges when retrofitting multi-storey buildings with interior thermal insulation",
abstract = "Today, approximately 25 {\%} of the apartments in the Danish multi-storey stock of more than two stories are found in buildings with masonry facades erected in the period 1850-1930. Of these apartments, 71 {\%} are situated in Copenhagen, the Danish capital. The building traditions and norms in force during the period entail that these buildings share similar characteristics, including solid masonry walls and embedded wooden components. The energy use and indoor climate was not in focus during construction, wherefore the current occupants cannot expect modern levels of thermal comfort and the section include a considerable energy saving potential. It is evident that thermal comfort and energy use can be improved by increasing the thermal resistance of the fa{\cc}ade. With focus on the masonry part of the total fa{\cc}ade area, this can be achieved with thermal insulation applied to the interior or exterior surface. While application to the exterior surface is the best solution from a building physics point of view, the retention of the exterior fa{\cc}ade expression is often a desire from the owner or a preservation requirement, leaving application to the interior surface as the only possibility. The buildings from the period have been investigated to determine the degree of shared characteristics within the building segment, showing similar building techniques with consistent thin spandrels under the windows and a low share of available interior surface area for the application of insulation. There were performed thermal simulations of characteristic fa{\cc}ade sections in 3-dimensional models, finding that insulation of the spandrel can achieve up to 40 {\%} of the maximum possible reduction achievable from reducing the thermal transmittance by retrofitting the masonry with interior insulation. The influence on the hygrothermal conditions when applying interior thermal insulation to solid masonry walls have been investigated experimentally in a case study and by comparative analyses of results from two field experiments. The case study was 2 rooms in a dormitory with a normal indoor moisture load, situated at an urban location. The study showed how retrofitting the interior surface of a solid masonry spandrel with a diffusion open thermal insulation system changed the hygrothermal balance in the wall, resulting in a colder and wetter wall with similar conditions throughout the wall. Evaluation of the case study, based on measurements and on-site investigations, showed no calculated or observed risks of moisture-induced damage. The field experiments were designed and constructed with an extensive measurement program, exposed to a high indoor moisture load and located in a rural area. The measurements were used for comparative analyses, to investigate the difference in hygrothermal performance of different interior thermal insulation systems, applied to the entire masonry surface or with some variations within the systems. The comparative analyses were based on the measured relative humidity, temperature and on mathematical damage models able to take exposure time into consideration. The damage models were used to compare the calculated risks of moisture-induced damage in the different systems. The results of the comparative analyses with the boundary conditions of the field experiments showed: > Application of a thermal insulation system depending on a tight vapour barrier or a diffusion open thermal insulation system resulted in an increase in calculated mould germination and growth on the masonry surface behind the insulation. > Application of a thermal insulation system depending on a tight vapour barrier resulted in an increase in calculated irreversible wooden decay in the wooden beam (floor joist), compared to other insulation systems and an un-insulated wall. > Hydrophobizing the exterior masonry surface with a hydrophobic fa{\cc}ade treatment had an overall positive effect on the hygrothermal conditions, and can be further improved by replacing a part of the moisture-open insulation with autoclaved aerated concrete.",
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Odgaard, TR 2019, Challenges when retrofitting multi-storey buildings with interior thermal insulation. B Y G D T U. Rapport, no. R-386, Technical University of Denmark, Department of Civil Engineering.

Challenges when retrofitting multi-storey buildings with interior thermal insulation. / Odgaard, Tommy Riviere.

Technical University of Denmark, Department of Civil Engineering, 2019. 312 p. (B Y G D T U. Rapport; No. R-386).

Research output: Book/ReportPh.D. thesisResearch

TY - BOOK

T1 - Challenges when retrofitting multi-storey buildings with interior thermal insulation

AU - Odgaard, Tommy Riviere

PY - 2019

Y1 - 2019

N2 - Today, approximately 25 % of the apartments in the Danish multi-storey stock of more than two stories are found in buildings with masonry facades erected in the period 1850-1930. Of these apartments, 71 % are situated in Copenhagen, the Danish capital. The building traditions and norms in force during the period entail that these buildings share similar characteristics, including solid masonry walls and embedded wooden components. The energy use and indoor climate was not in focus during construction, wherefore the current occupants cannot expect modern levels of thermal comfort and the section include a considerable energy saving potential. It is evident that thermal comfort and energy use can be improved by increasing the thermal resistance of the façade. With focus on the masonry part of the total façade area, this can be achieved with thermal insulation applied to the interior or exterior surface. While application to the exterior surface is the best solution from a building physics point of view, the retention of the exterior façade expression is often a desire from the owner or a preservation requirement, leaving application to the interior surface as the only possibility. The buildings from the period have been investigated to determine the degree of shared characteristics within the building segment, showing similar building techniques with consistent thin spandrels under the windows and a low share of available interior surface area for the application of insulation. There were performed thermal simulations of characteristic façade sections in 3-dimensional models, finding that insulation of the spandrel can achieve up to 40 % of the maximum possible reduction achievable from reducing the thermal transmittance by retrofitting the masonry with interior insulation. The influence on the hygrothermal conditions when applying interior thermal insulation to solid masonry walls have been investigated experimentally in a case study and by comparative analyses of results from two field experiments. The case study was 2 rooms in a dormitory with a normal indoor moisture load, situated at an urban location. The study showed how retrofitting the interior surface of a solid masonry spandrel with a diffusion open thermal insulation system changed the hygrothermal balance in the wall, resulting in a colder and wetter wall with similar conditions throughout the wall. Evaluation of the case study, based on measurements and on-site investigations, showed no calculated or observed risks of moisture-induced damage. The field experiments were designed and constructed with an extensive measurement program, exposed to a high indoor moisture load and located in a rural area. The measurements were used for comparative analyses, to investigate the difference in hygrothermal performance of different interior thermal insulation systems, applied to the entire masonry surface or with some variations within the systems. The comparative analyses were based on the measured relative humidity, temperature and on mathematical damage models able to take exposure time into consideration. The damage models were used to compare the calculated risks of moisture-induced damage in the different systems. The results of the comparative analyses with the boundary conditions of the field experiments showed: > Application of a thermal insulation system depending on a tight vapour barrier or a diffusion open thermal insulation system resulted in an increase in calculated mould germination and growth on the masonry surface behind the insulation. > Application of a thermal insulation system depending on a tight vapour barrier resulted in an increase in calculated irreversible wooden decay in the wooden beam (floor joist), compared to other insulation systems and an un-insulated wall. > Hydrophobizing the exterior masonry surface with a hydrophobic façade treatment had an overall positive effect on the hygrothermal conditions, and can be further improved by replacing a part of the moisture-open insulation with autoclaved aerated concrete.

AB - Today, approximately 25 % of the apartments in the Danish multi-storey stock of more than two stories are found in buildings with masonry facades erected in the period 1850-1930. Of these apartments, 71 % are situated in Copenhagen, the Danish capital. The building traditions and norms in force during the period entail that these buildings share similar characteristics, including solid masonry walls and embedded wooden components. The energy use and indoor climate was not in focus during construction, wherefore the current occupants cannot expect modern levels of thermal comfort and the section include a considerable energy saving potential. It is evident that thermal comfort and energy use can be improved by increasing the thermal resistance of the façade. With focus on the masonry part of the total façade area, this can be achieved with thermal insulation applied to the interior or exterior surface. While application to the exterior surface is the best solution from a building physics point of view, the retention of the exterior façade expression is often a desire from the owner or a preservation requirement, leaving application to the interior surface as the only possibility. The buildings from the period have been investigated to determine the degree of shared characteristics within the building segment, showing similar building techniques with consistent thin spandrels under the windows and a low share of available interior surface area for the application of insulation. There were performed thermal simulations of characteristic façade sections in 3-dimensional models, finding that insulation of the spandrel can achieve up to 40 % of the maximum possible reduction achievable from reducing the thermal transmittance by retrofitting the masonry with interior insulation. The influence on the hygrothermal conditions when applying interior thermal insulation to solid masonry walls have been investigated experimentally in a case study and by comparative analyses of results from two field experiments. The case study was 2 rooms in a dormitory with a normal indoor moisture load, situated at an urban location. The study showed how retrofitting the interior surface of a solid masonry spandrel with a diffusion open thermal insulation system changed the hygrothermal balance in the wall, resulting in a colder and wetter wall with similar conditions throughout the wall. Evaluation of the case study, based on measurements and on-site investigations, showed no calculated or observed risks of moisture-induced damage. The field experiments were designed and constructed with an extensive measurement program, exposed to a high indoor moisture load and located in a rural area. The measurements were used for comparative analyses, to investigate the difference in hygrothermal performance of different interior thermal insulation systems, applied to the entire masonry surface or with some variations within the systems. The comparative analyses were based on the measured relative humidity, temperature and on mathematical damage models able to take exposure time into consideration. The damage models were used to compare the calculated risks of moisture-induced damage in the different systems. The results of the comparative analyses with the boundary conditions of the field experiments showed: > Application of a thermal insulation system depending on a tight vapour barrier or a diffusion open thermal insulation system resulted in an increase in calculated mould germination and growth on the masonry surface behind the insulation. > Application of a thermal insulation system depending on a tight vapour barrier resulted in an increase in calculated irreversible wooden decay in the wooden beam (floor joist), compared to other insulation systems and an un-insulated wall. > Hydrophobizing the exterior masonry surface with a hydrophobic façade treatment had an overall positive effect on the hygrothermal conditions, and can be further improved by replacing a part of the moisture-open insulation with autoclaved aerated concrete.

M3 - Ph.D. thesis

SN - 9788778774811

T3 - B Y G D T U. Rapport

BT - Challenges when retrofitting multi-storey buildings with interior thermal insulation

PB - Technical University of Denmark, Department of Civil Engineering

ER -

Odgaard TR. Challenges when retrofitting multi-storey buildings with interior thermal insulation. Technical University of Denmark, Department of Civil Engineering, 2019. 312 p. (B Y G D T U. Rapport; No. R-386).