Experimental and numerical assessment of rainwater intrusion in ventilated facades with open joints

Abstract

Rainwater ingress is the primary source of premature degradation of building materials. However, currently little quantitative information is available on rain water management of wall systems in general, and ventilated facades in particular: how much water infiltrates, how much water crosses the cavity, and what is the impact on the hygrothermal performance? To understand the water and moisture management of ventilated façades with open joints, experimental watertightness tests were conducted to assess the impact of cavity depth, width of the panel joints, out-of-plane installation of panels, and dimensions of supporting structure. A test setup was designed to quatify the rainwater infiltration in the wall cavity. Subsequently, an experimental study was done on the rainwater infiltration into the insulation layer for different materials (PU and mineral wool), airtightness level, and workmanship (with and without common deficiencies). The results from both test series were then used to simulate the impact of rainwater ingress on the hygrothermal behavior by means numerical simulations. 1D hygrothermal simulations were conducted for ventilated facades located in Brussels (Belgium), Bergen (Norway), and Lisbon (Portugal). The risk for mold problems is small as the drying potential due to the ventilated cavity is large. However, infiltration may have a significant impact on the latent heat transport and annual heat flux. For a cavity of 40 mm the increase in heat flow is limited to 0.4%, whereas for a 20 mm cavity the increase rises to 10.5%. The installation of a WRB reduces the infiltration of water into the insulation, but the effect of installation errors also increases due to reduced drying potential.

Keywords

Ventilated facades rainwater management watertightness hygrothermal simulations

Get full access to this article

View all access options for this article.

References

Arce Recatalá

García Morales

Van den Bossche

(2020) Pressure-equalised façade systems: Evaluation of current watertightness test standards used to assess the performance of enclosure components. Journal of Building Physics 43(5): 369–397. DOI: 10.1177/1744259119880284.

ASHRAE (2016) ASHRAE 160-Criteria for Moisture-Control Design Analysis in Buildings. ASHRAE.

Arce-Recatalá

García-Morales

Van den Bossche

(2020) Quantifying wind-driven rain intrusion–a comparative study on the water management features of different types of rear-ventilated facade systems. In: E3S Web of Conferences (Vol. 172, p. 23007). EDP Sciences.

Beaulieu

Bomberg

Cornick

, et al. (2002) Final report from Task 8 of MEWS Project (T8-03)-Hygrothermal response of exterior wall systems to climate loading: methodology and interpretation of results for stucco, EIFS, masonry and siding clad wood-frame walls. Research Rep 118.

Blocken

Carmeliet

(2004) A review of wind-driven rain research in building science. Journal of Wind Engineering and Industrial Aerodynamics 92(13): 1079–1130. DOI: 10.1016/j.jweia.2004.06.003.

Calle

Coupillie

Janssens

, et al. (2020) Implementation of rainwater infiltration measurements in hygrothermal modelling of non-insulated brick cavity walls. Journal of Building Physics 43(6): 477–502. DOI: 10.1177/1744259119883909.

Carretero-Ayuso

Moreno-Cansado

de Brito

(2018) General survey of construction-related complaints in recent buildings in Spain. International Journal of Civil Engineering 16: 1781–1796. DOI: 10.1007/s40999-017-0259-7.

Couper

(1974) Factors affecting the production of surface runoff from wind-driven rain. Presented at the RILEM Symposium on Moisture Problems in Buildings.

de Freitas

(2013) A state-of-the-art report on building pathology. CIB-W086 Building Pathology.

10.

De Vos

Blommaert

Van Den Bossche

(2020) Statistical analysis on Belgian building defects. In: XV International Conference on Durability of Building Materials and Components (DBMC 2020) (pp. 1751–1758). International Center for Numerical Methods in Engineering (CIMNE). DOI: 10.23967/dbmc.2020.130.

11.

De Meersman

Van Den Bossche

Janssens

(2014) HAM simulation of the drying out capacity of water ingress in wooden constructions. In: 10th Nordic Symposium on Building Physics (pp. 1116–1123).

12.

European Committee for Standardization (CEN) (2012) ISO 13788:2012 Hygrothermal performance of building components and building elements - Internal surface temperature to avoid critical surface humidity and interstitial condensation - calculation methods. Brussels: CEN.

13.

European Committee for Standardization (CEN) (2000a) EN 12155 - Curtain walling - Watertightness - Laboratory test under static pressure. Brussels: CEN.

14.

European Committee for Standardization (CEN) (2000b) EN 12114 Thermal performance of buildings - Air permeability of building components and building elements - Laboratory test method. Brussels: CEN.

15.

Herbert

MRM

(1974) Open-jointed Rain Screen Claddings. Building Research Establishment, Garston Watford.

16.

Isaksen

(1966) Rain penetration in joints. Influence of dimensions and shape of joints on rain penetration. Available at: https://sintef.brage.unit.no/sintef-xmlui/handle/11250/2408115 (accessed 10 February 2023).

17.

Killip

Cheetham

(1984) The prevention of rain penetration through external walls and joints by means of pressure equalization. Building and Environment 19(2): 81–91. DOI: 10.1016/0360-1323(84)90033-7.

18.

Kumaran

Mukhopadhyaya

Cornick

, et al. (2003) An Integrated methodology to develop moisture management strategies for exterior wall systems. In: Proceedings of the 9th Canadian Conference on Building Science and Technology (pp. 45–62).

19.

Langmans

Desta

Alderweireldt

, et al. (2016) Field study on the air change rate behind residential rainscreen cladding systems: A parameter analysis. Building and Environment 95: 1–2. DOI: 10.1016/j.buildenv.2015.09.012.

20.

Mas

Gutiérrez

Gil

, et al. (2011) Design and construction recommendations to improve impermeability in rainscreen walls built with natural stone coverings. Construction and Building Materials 25(4): 1753–1761. DOI: 10.1016/j.conbuildmat.2010.11.091.

21.

Moore

Lacasse

(2020) Approach to incorporating water entry and water loads to wall assemblies when completing hygrothermal modelling. In: Symposium on Building Science and the Physics of Building Enclosure Performance (pp. 157–176). ASTM International. DOI: 10.1520/STP161720180088.

22.

Observatoire de la qualité de la construction Edition (2021). Observatoire de la qualité de la construction Edition. Agence Qualité Construction.

23.

Rahiminejad

Khovalyg

(2023) Experimental study of the hydrodynamic and thermal performances of ventilated wall structures. Building and Environment 233: 110114.

24.

Rahiminejad

Khovalyg

(2021) Review on ventilation rates in the ventilated air-spaces behind common wall assemblies with external cladding. Building and Environment 190: 107538. DOI: 10.1016/j.buildenv.2020.107538.

25.

Recatala

Morales

Van Den Bossche

(2018) Experimental assessment of rainwater management of a ventilated façade. Journal of Building Physics 42(1): 38–67. DOI: 10.1177/1744259117719077.

26.

Straube

Finch

(2007) Ventilated wall claddings: Review, field performance, and hygrothermal modeling. Proceedings of Buildings X Conference - Thermal Performance of the Exterior Envelopes of Buildings X, Clearwater Beach, FL

27.

Støver

Sundsøy

Andenæs

, et al. (2022) Rain intrusion through horizontal joints in facade panel systems—Experimental investigation. Buildings 12(10): 1497. DOI: 10.3390/buildings12101497.

28.

Teasdale-St-Hilaire

Derome

(2005) State-of-the-art review of simulated rain infiltration and environmental loading for large-scale building envelope testing. ASHRAE Transactions 111: 389.

29.

Van Den Bossche

Janssens

Moore

, et al. (2020) Development of numerical model for determination of pressure equalization in facades during wet conditions. Building and Environment 178: 106919. DOI: 10.1016/j.buildenv.2020.106919.

30.

Van Linden

Lacasse

Van Den Bossche

(2022) Drainage of infiltrated rainwater in wall assemblies: Test method, experimental quantification, and recommendations. Journal of Building Physics 46(2): 176–210. DOI: 10.1177/17442591221121932.

31.

Van Linden

Van Den Bossche

(2022) Review of rainwater infiltration rates in wall assemblies. Building and Environment 219: 109213. DOI: 10.1016/j.buildenv.2022.109213.

32.

Wetenschappelijk en technisch centrum voor het bouwbedrijf (2015) TV 255 Luchtdichtheid van gebouwen. WTCB.