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Why do we often get biological growth on thin rendering on thermal insulation constructions?

Johansson, Sanne LU ; Wadsö, Lars LU and Sandin, Kenneth LU (2008) Proceedings of the 8th Symposium on Building Physics in the Nordic Contries In Proceedings of the 8th Symposium on Building Physics in the Nordic Contries 2. p.919-926
Abstract
If one takes a closer look at almost any building facade one will find biological growth. Although this can be seen as an integral part of an antique building, for modern buildings it is in most cases seen as an aesthetical problem. All building facades will most likely be discolored by biological growth by time, but in Sweden we have had many cases of newly built rendered facades that have been discolored much more rapidly than usual. The problem is believed to occur mainly on thin rendering applied on thermal insulation -which is a common building facade construction in Sweden -but apart from this, it is difficult to find clear indications of which facades that will be affected. As it is well known that different biological organisms has... (More)
If one takes a closer look at almost any building facade one will find biological growth. Although this can be seen as an integral part of an antique building, for modern buildings it is in most cases seen as an aesthetical problem. All building facades will most likely be discolored by biological growth by time, but in Sweden we have had many cases of newly built rendered facades that have been discolored much more rapidly than usual. The problem is believed to occur mainly on thin rendering applied on thermal insulation -which is a common building facade construction in Sweden -but apart from this, it is difficult to find clear indications of which facades that will be affected. As it is well known that different biological organisms has different requirements in physical factors (especially temperature and relative humidity) for germination and growth on any substrate, it is important to define which conditions the organisms needs to grow on a building fasade. We have studied the temperature and relative humidity conditions on the surfaces of different rendered facade constructions. We find that the surface temperature on a facade of thin rendering on thermal insulation drops quickly during nights, as these constructions have low heat capacity in the rendering layer. This leads to high relative humidity and even condensation, during clear nights. Other abiotic factors that seem also to influence the risk for growth are surface color and rendering structure. From the temperature and relative humidity measurements in this study, we aim at giving insight of the surface climate on a building façade in order to fully understand the rendered façade as a biological habitat. (Less)
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author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
facade, rendering, mould growth, temperature, ETICS, moisture
in
Proceedings of the 8th Symposium on Building Physics in the Nordic Contries
editor
Rode, Carsten
volume
2
pages
8 pages
conference name
Proceedings of the 8th Symposium on Building Physics in the Nordic Contries
ISBN
978-87-7877-265-7
language
English
LU publication?
yes
id
877f7d0d-68bf-4a31-a91c-e92b2283a90f (old id 1542785)
date added to LUP
2010-02-04 17:16:49
date last changed
2016-04-16 12:22:58
@inproceedings{877f7d0d-68bf-4a31-a91c-e92b2283a90f,
  abstract     = {If one takes a closer look at almost any building facade one will find biological growth. Although this can be seen as an integral part of an antique building, for modern buildings it is in most cases seen as an aesthetical problem. All building facades will most likely be discolored by biological growth by time, but in Sweden we have had many cases of newly built rendered facades that have been discolored much more rapidly than usual. The problem is believed to occur mainly on thin rendering applied on thermal insulation -which is a common building facade construction in Sweden -but apart from this, it is difficult to find clear indications of which facades that will be affected. As it is well known that different biological organisms has different requirements in physical factors (especially temperature and relative humidity) for germination and growth on any substrate, it is important to define which conditions the organisms needs to grow on a building fasade. We have studied the temperature and relative humidity conditions on the surfaces of different rendered facade constructions. We find that the surface temperature on a facade of thin rendering on thermal insulation drops quickly during nights, as these constructions have low heat capacity in the rendering layer. This leads to high relative humidity and even condensation, during clear nights. Other abiotic factors that seem also to influence the risk for growth are surface color and rendering structure. From the temperature and relative humidity measurements in this study, we aim at giving insight of the surface climate on a building façade in order to fully understand the rendered façade as a biological habitat.},
  author       = {Johansson, Sanne and Wadsö, Lars and Sandin, Kenneth},
  booktitle    = {Proceedings of the 8th Symposium on Building Physics in the Nordic Contries},
  editor       = {Rode, Carsten},
  isbn         = {978-87-7877-265-7},
  keyword      = {facade,rendering,mould growth,temperature,ETICS,moisture},
  language     = {eng},
  pages        = {919--926},
  title        = {Why do we often get biological growth on thin rendering on thermal insulation constructions?},
  volume       = {2},
  year         = {2008},
}