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Strategies for Enhanced Energy Efficiency and Moisture Management in Brick–AAC Cavity Walls

Kahangi Shahreza, Seyedmohammad LU orcid ; Bayat Pour, Mohsen LU ; Abdul Hamid, Akram LU orcid and Molnár, Miklós LU (2025) 1. p.804-819
Abstract
In Sweden, cavity walls constructed with autoclaved aerated concrete (AAC) inner leaves and clay brick outer leaves were a common design choice during the 1950s to 1970s. These walls often result in relatively extensive heat losses, leading to reduced indoor thermal comfort. Further, moisture-related issues like frost damage and interior dampness are reported for this wall type. This indicates the importance of enhancing the hygric and thermal performance of such walls. Since preservation of the protected facade due to heritage values limits external interventions, interior insulation becomes a primary focus for energy efficiency improvements. This study aims to explore various maintenance and renovation measures to enhance the performance... (More)
In Sweden, cavity walls constructed with autoclaved aerated concrete (AAC) inner leaves and clay brick outer leaves were a common design choice during the 1950s to 1970s. These walls often result in relatively extensive heat losses, leading to reduced indoor thermal comfort. Further, moisture-related issues like frost damage and interior dampness are reported for this wall type. This indicates the importance of enhancing the hygric and thermal performance of such walls. Since preservation of the protected facade due to heritage values limits external interventions, interior insulation becomes a primary focus for energy efficiency improvements. This study aims to explore various maintenance and renovation measures to enhance the performance of these walls, namely a) repointing the outer leaf (face bricks), b) adding interior insulation with different properties, and c) combining interior insulation with repointing. The study employs hygrothermal simulations for Gothenburg, the location with one of the highest exposure to wind-driven rain (WDR) in Sweden. The results highlight that an efficient way to improve the wall condition, a balance between moisture accumulation and heat loss, is to add vapor-open insulation followed by repointing, especially for walls in a deficient condition. Repointing alone effectively reduces moisture accumulation for cavity walls with brick masonry in a deficient condition, with a limited impact on improving thermal comfort. XPS insulation, a vapor-tight system, reduces heat loss but increases moisture in the AAC layer, posing potential moisture-related issues. Adding capillary-active insulation followed by repointing improves thermal comfort without significant moisture accumulation in the AAC layer. (Less)
Please use this url to cite or link to this publication:
author
; ; and
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
Repointing, Masonry cavity wall, Internal insulation, Dampness, Autoclaved aerated concrete (AAC), Moisture content, Heat loss
host publication
18th International Brick and Block Masonry Conference
volume
1
pages
16 pages
publisher
Springer Nature
external identifiers
  • scopus:85213298559
ISBN
978-3-031-73313-0
978-3-031-73314-7
DOI
10.1007/978-3-031-73314-7_62
language
English
LU publication?
yes
id
9d5f364f-df52-4b2c-ad80-12a734936683
date added to LUP
2024-12-24 16:46:29
date last changed
2025-07-12 19:07:32
@inproceedings{9d5f364f-df52-4b2c-ad80-12a734936683,
  abstract     = {{In Sweden, cavity walls constructed with autoclaved aerated concrete (AAC) inner leaves and clay brick outer leaves were a common design choice during the 1950s to 1970s. These walls often result in relatively extensive heat losses, leading to reduced indoor thermal comfort. Further, moisture-related issues like frost damage and interior dampness are reported for this wall type. This indicates the importance of enhancing the hygric and thermal performance of such walls. Since preservation of the protected facade due to heritage values limits external interventions, interior insulation becomes a primary focus for energy efficiency improvements. This study aims to explore various maintenance and renovation measures to enhance the performance of these walls, namely a) repointing the outer leaf (face bricks), b) adding interior insulation with different properties, and c) combining interior insulation with repointing. The study employs hygrothermal simulations for Gothenburg, the location with one of the highest exposure to wind-driven rain (WDR) in Sweden. The results highlight that an efficient way to improve the wall condition, a balance between moisture accumulation and heat loss, is to add vapor-open insulation followed by repointing, especially for walls in a deficient condition. Repointing alone effectively reduces moisture accumulation for cavity walls with brick masonry in a deficient condition, with a limited impact on improving thermal comfort. XPS insulation, a vapor-tight system, reduces heat loss but increases moisture in the AAC layer, posing potential moisture-related issues. Adding capillary-active insulation followed by repointing improves thermal comfort without significant moisture accumulation in the AAC layer.}},
  author       = {{Kahangi Shahreza, Seyedmohammad and Bayat Pour, Mohsen and Abdul Hamid, Akram and Molnár, Miklós}},
  booktitle    = {{18th International Brick and Block Masonry Conference}},
  isbn         = {{978-3-031-73313-0}},
  keywords     = {{Repointing; Masonry cavity wall; Internal insulation; Dampness; Autoclaved aerated concrete (AAC); Moisture content; Heat loss}},
  language     = {{eng}},
  pages        = {{804--819}},
  publisher    = {{Springer Nature}},
  title        = {{Strategies for Enhanced Energy Efficiency and Moisture Management in Brick–AAC Cavity Walls}},
  url          = {{http://dx.doi.org/10.1007/978-3-031-73314-7_62}},
  doi          = {{10.1007/978-3-031-73314-7_62}},
  volume       = {{1}},
  year         = {{2025}},
}