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Control of moisture safety design by comparison between calculations and measurements in passive house walls made of wood

Mundt Petersen, Solof LU and Harderup, Lars-Erik LU (2011) XII DBMC - XII International Conference on Durability of Building Materials and Components In Proceedings fo the 12th International Conference on Durability of Buildings Materials and Components - XII DBMC p.25-32
Abstract
The use of passive house technique has been used in a new wood framed building in Sweden. Besides the positive effect of reduced energy need, highly insulated wooden houses often have a higher risk of moisture and mould problems. The reason is that critical positions is more exposed to higher relative humidity compared to ordinary houses with thinner insulation. To investigate if an external wall has been correctly designed and constructed it has been investigated both with hourly measurements and by calculations with WUFI 5.0.

The aim of this study is to investigate the result of the moisture design process and the way changes in the design influence the moisture safety with real climate conditions. The study also investigates if... (More)
The use of passive house technique has been used in a new wood framed building in Sweden. Besides the positive effect of reduced energy need, highly insulated wooden houses often have a higher risk of moisture and mould problems. The reason is that critical positions is more exposed to higher relative humidity compared to ordinary houses with thinner insulation. To investigate if an external wall has been correctly designed and constructed it has been investigated both with hourly measurements and by calculations with WUFI 5.0.

The aim of this study is to investigate the result of the moisture design process and the way changes in the design influence the moisture safety with real climate conditions. The study also investigates if WUFI 5.0 is a reliable tool to use in the construction design process. This was investigated by comparisons between measured and calculated relative humidity and temperature in different positions in an exterior wooden wall from April 2009 to October 2010.

In the original design the outer wooden studs have no protecting layer from the ventilated air gap behind the façade. Results from calculations with WUFI 5.0 shows that it is sufficient with a thin protecting thermal insulation on the outside of outer studs to considerably improve the moisture conditions in the outer parts ot the wall. If we never want the relative humidity to be above the critical level, at least 87 mm of insulation have to be applied on the outside of the wooden studs.

Comparisons between measurements and calculations show that WUFI 5.0 can be a reliable tool in moisture design of highly insulated wood framed walls. To get safe results it is important to use reliable climate and correct assumption about the air flow in the air gap behind the façade material. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
moisture, measurements, WUFI, comparisons, mould
in
Proceedings fo the 12th International Conference on Durability of Buildings Materials and Components - XII DBMC
editor
Peixoto de Freitas, Vasco; Corvacho, Helena; Lacasse, Michael; ; and
pages
8 pages
publisher
FEUP Edicoes
conference name
XII DBMC - XII International Conference on Durability of Building Materials and Components
ISBN
978-972-752-132-6
language
English
LU publication?
yes
id
bd5e4fb2-e325-4162-8e22-b8c7c1faf8c6 (old id 5218672)
date added to LUP
2015-03-28 08:46:09
date last changed
2016-04-16 07:33:36
@inproceedings{bd5e4fb2-e325-4162-8e22-b8c7c1faf8c6,
  abstract     = {The use of passive house technique has been used in a new wood framed building in Sweden. Besides the positive effect of reduced energy need, highly insulated wooden houses often have a higher risk of moisture and mould problems. The reason is that critical positions is more exposed to higher relative humidity compared to ordinary houses with thinner insulation. To investigate if an external wall has been correctly designed and constructed it has been investigated both with hourly measurements and by calculations with WUFI 5.0.<br/><br>
The aim of this study is to investigate the result of the moisture design process and the way changes in the design influence the moisture safety with real climate conditions. The study also investigates if WUFI 5.0 is a reliable tool to use in the construction design process. This was investigated by comparisons between measured and calculated relative humidity and temperature in different positions in an exterior wooden wall from April 2009 to October 2010. <br/><br>
In the original design the outer wooden studs have no protecting layer from the ventilated air gap behind the façade. Results from calculations with WUFI 5.0 shows that it is sufficient with a thin protecting thermal insulation on the outside of outer studs to considerably improve the moisture conditions in the outer parts ot the wall. If we never want the relative humidity to be above the critical level, at least 87 mm of insulation have to be applied on the outside of the wooden studs.<br/><br>
Comparisons between measurements and calculations show that WUFI 5.0 can be a reliable tool in moisture design of highly insulated wood framed walls. To get safe results it is important to use reliable climate and correct assumption about the air flow in the air gap behind the façade material.},
  author       = {Mundt Petersen, Solof and Harderup, Lars-Erik},
  booktitle    = {Proceedings fo the 12th International Conference on Durability of Buildings Materials and Components - XII DBMC},
  editor       = {Peixoto de Freitas, Vasco and Corvacho, Helena and Lacasse, Michael},
  isbn         = {978-972-752-132-6},
  keyword      = {moisture,measurements,WUFI,comparisons,mould},
  language     = {eng},
  pages        = {25--32},
  publisher    = {FEUP Edicoes},
  title        = {Control of moisture safety design by comparison between calculations and measurements in passive house walls made of wood},
  year         = {2011},
}