"On the hygrothermal behaviour of brick veneer cladded timber frame walls: the role of the vapour diffusion resistance of the wind barrier"

To meet the increasingly stringent energy efficiency requirements, the market share of timber frame houses is steadily growing across Europe. Timber frame walls in Belgium are typically combined with a brick veneer cladding, which has a high buffer capacity for wind driven rain and a relative low cavity ventilation rate. Consequently, moisture levels inside the cavity may become high, which might lead to an inward vapour flow and an elevated moisture content in the inner part of the wall. In combination with a moisture sensitive timber frame inner wall, this could result in an increased risk of fungal growth. Therefore, the aim of the current paper is to study the hygrothermal performance of timber frame walls with brick veneer cladding in a moderate sea climate. To do so, a field study on two typical timber frame walls with brick veneer cladding is conducted. The field study specifically focuses on the contradictory criterion for the vapour diffusion resistance of the wind barrier for summer and winter conditions. The data of the in-situ measuring campaign indicates that the differences between set-ups with wind barriers with different vapour diffusion resistance is rather limited. In addition, a parameter analysis is conducted using a numerical model. The parameter analysis indicates an increased mould growth risk due to the brick veneer cladding and the importance of providing hygroscopic moisture buffer capacity inside the wall.

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Hygrothermal behaviour of timber frame walls finished with a brick veneer cladding

Energy Procedia ◽

10.1016/j.egypro.2017.09.633 ◽

2017 ◽

Vol 132 ◽

pp. 363-368 ◽

Cited By ~ 3

Author(s):

Michiel Vanpachtenbeke ◽

Jelle Langmans ◽

Jan Van den Bulcke ◽

Joris Van Acker ◽

Staf Roels

Keyword(s):

Timber Frame ◽

Brick Veneer ◽

Hygrothermal Behaviour

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Untersuchungen zum Diffusionswiderstand von Holzwerkstoffen | Diffusion resistance of timber materials

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2005.0100 ◽

2005 ◽

Vol 156 (3-4) ◽

pp. 100-103

Author(s):

Rudolf Popper ◽

Peter Niemz ◽

Gerhild Eberle

Keyword(s):

Relative Humidity ◽

Water Vapour ◽

Middle Lamella ◽

Solid Wood ◽

Diffusion Resistance ◽

Water Vapour Diffusion ◽

Wood Panels ◽

Vapour Diffusion ◽

Wet Climate ◽

Panel Thickness

The water vapour diffusion resistance of timber materials were tested in a wet climate (relative humidity ranging from 100%to 65% at 20 °C) and in a dry climate (relative humidity ranging from 0% to 65% and from 0% to 35% at 20 °c) with variation by relative humidity and vapour pressure gradient. The diffusion resistance of multilayer solid wood panels lies under or within the range of the solid wood (spruce), tending even to a lower range. This can be attributed to the loosely inserted middle lamella of the used solid wood panels, which were not correctly glued by the manufacturer. The diffusion resistance of the solid wood panels increases with decreasing moisture content and decreasing panel thickness, as well as with increasing water vapour gradient from 818 to 1520 Pa. There were clear differences between the tested timber materials. The diffusion resistance of particle composites is strongly dependent on the specific gravity. Due to laminar particles OSBs(Oriented Strand Boards) have a larger diffusion resistance than chipboards. The water vapour diffusion resistance of OSBs lies within the range of plywood.

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Effects of exposure on water relations and photosynthesis of western hemlock in habitat forms

Canadian Journal of Forest Research ◽

10.1139/x76-006 ◽

1976 ◽

Vol 6 (1) ◽

pp. 40-48 ◽

Cited By ~ 4

Author(s):

R. A. Keller ◽

E. B. Tregunna

Keyword(s):

Light Intensity ◽

Water Content ◽

Water Vapour ◽

Western Hemlock ◽

Diffusion Resistance ◽

The Sun ◽

Evaporative Demand ◽

Photosynthetic Rates ◽

Water Vapour Diffusion ◽

Vapour Diffusion

Measurements of relative turgidity, transpiration rates, and photosynthetic rates on sun-grown and shade-grown western hemlock (Tsugaheterophylla (Raf.) Sarg.) were used to indicate effects of varying degrees of exposure.The sun-adapted form had low photosynthetic rates but maintained its water content under conditions of high evaporative demand. The shade-adapted form desiccated under exposed conditions, and in contrast with the sun-adapted form, its water vapour diffusion resistance decreased with increasing light intensity.

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Hygric Properties of HPC with Natural Pozzolana

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.677.93 ◽

2016 ◽

Vol 677 ◽

pp. 93-97 ◽

Cited By ~ 1

Author(s):

Jaroslava Koťátková ◽

Monika Čáchová ◽

Dana Koňáková ◽

Eva Vejmelková

Keyword(s):

Water Vapour ◽

High Performance ◽

High Performance Concrete ◽

Diffusion Resistance ◽

Supplementary Cementitious Material ◽

Water Vapour Transport ◽

Water Vapour Diffusion ◽

Natural Pozzolana ◽

Vapour Diffusion ◽

Liquid Water Transport

The water vapour transport and the liquid water transport of high performance concrete (HPC) with the content of natural pozzolana are the described in this paper. Studied properties are presented by means of water vapour diffusion coefficient, water vapour diffusion resistance factor and absorption coefficient respectively. The natural pozzolana (NP), namely natural zeolite, is used as supplementary cementitious material which affects the durability properties of the end product. The obtained results revealed the effectiveness of NP in the terms of both studied properties when used in small amounts, i.e. at about 20% of cement weight. On the other hand substitutions higher than 40% result in worsening of the resistance of the concrete to water and water vapour ingress and its movement trough the material.

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A novel and flexible test setup to measure the vapour diffusion resistance of building materials and wall components

MATEC Web of Conferences ◽

10.1051/matecconf/201928202057 ◽

2019 ◽

Vol 282 ◽

pp. 02057

Author(s):

Evy Vereecken ◽

Wouter Van De Walle ◽

Staf Roels

Keyword(s):

Building Materials ◽

Test Sample ◽

Masonry Wall ◽

Diffusion Resistance ◽

The Novel ◽

Component Level ◽

Cooling Plate ◽

Test Setup ◽

Vapour Diffusion ◽

Vapour Flux

A novel test setup and procedure to measure the vapour diffusion resistance of building materials and components are presented. In this test setup, a vapour flux across the test sample is induced by cooling down one of the sample’s surfaces by a cooling plate. The cooling plate also acts as a vapour tight plane and hence condensation is created. The vapour diffusion resistance is, via a Glaser-based calculation, inferred from the mass of condensation. Benefits of the novel procedure are its applicability to building components such as masonry, CLT, etc., and its larger flexibility in respect to the boundary conditions. The non-isothermal approach allows the induction of a large (and thus measurable) vapour flux while a quasi-constant relative humidity across the sample can be imposed. In the paper, the novel method is validated based on a bituminous impregnated fibreboard with known diffusion resistance. Thereafter, the method is applied to a masonry wall, showing the importance of diffusion measurements on the component level.

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The Role of Metallic Connections in the Global Behavior of Timber Frame Structural System of Tabique Walls

10.1007/978-3-030-90788-4_82 ◽

2021 ◽

pp. 1066-1080

Author(s):

José Padrão ◽

Jorge Pinto ◽

António Arede ◽

João Guedes

Keyword(s):

Global Behavior ◽

Structural System ◽

Timber Frame

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Role of policies and national programmes on innovations in timber-frame construction.

Innovation in forestry: territorial and value chain relationships ◽

10.1079/9781845936891.0204 ◽

2011 ◽

pp. 204-232 ◽

Cited By ~ 1

Author(s):

T. Nord ◽

S. Tykkä ◽

D. McCluskey ◽

F. Bajric ◽

L. Bouriaud ◽

...

Keyword(s):

Timber Frame ◽

National Programmes ◽

Frame Construction

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Mathematical Modeling of Chromium(Ш) Extraction by Emulsion Liquid Membrane

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.791-793.315 ◽

2013 ◽

Vol 791-793 ◽

pp. 315-319

Author(s):

Yao Zhong Xie ◽

De Jun Fei ◽

Ya Gu Dang ◽

Jian Xun Wu

Keyword(s):

Liquid Membrane ◽

Mass Transfer Process ◽

Reaction Model ◽

Reversible Reaction ◽

Transfer Model ◽

Diffusion Resistance ◽

Emulsion Liquid Membrane ◽

Primary Resistance ◽

Internal Phase

Advancing front model, carrier-facilitated transfer model and reversible reaction model were applied to simulate extracting chromium (Ш) from wastewater by emulsion liquid membrane using di-(2-ethylhexyl) phosphoric acid as carrier and Span-80 as surfactant. Parameters of the mathematic models were gained from the designed experiments, and the reversible reaction model can be used with a reasonably accuracy as estimates of chromium (Ш) permeation. The experimental results demonstrate that the role of reversibility of the chemical reaction between internal phase and membrane phase should be considered, and the diffusion resistance is the primary resistance of the mass transfer process.

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