Exterior insulation envelope retrofits in cold climates: Implications for moisture control

Craven, Colin; Garber-Slaght, Robbin

doi:10.1080/10789669.2014.887028

Cited by 18 publications

(22 citation statements)

References 5 publications

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“…However, the highly insulated walls may lead to a higher risk of moisture problems. Hygrothermal simulations have been widely used to investigate the hygrothermal performance of highly insulated walls (Maref et al, 2010;Arena et al, 2013;Parsons and Lieburn, 2013;Smegal et al, 2013;Craven and Garber-Slaght, 2014;Glass et al, 2015). However, the uncertainties of the input parameters may lead to discrepancies between simulation results and real performance of the walls.…”

Section: Introductionmentioning

confidence: 99%

Stochastic modelling of hygrothermal performance of highly insulated wood framed walls

Wang

2018

Building and Environment

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Recent years, the majority of building codes in North America require an energy efficient envelope to improve the building energy efficiency. There are different design strategies to achieve a higher insulation level of the wood framed building envelope, such as increasing the depth of stud cavity to accommodate thicker insulation or adding an exterior insulation while keeping the depth of stud cavity unchanged. However, the highly insulated walls may lead to a higher risk of moisture problems. The deep cavity walls will reduce the temperature of the wood sheathing, which may increase the potential for condensation and mold growth. The exterior insulated walls may result in a low drying capacity of the wood sheathing if the exterior insulation has a low vapour permeance. Although hygrothermal simulations have been widely used to investigate the moisture performance of wood framed walls, the uncertainty of the input parameters may lead to discrepancies between simulation results and real performance of the walls. This paper investigates the hygrothermal performance of highly insulated wood framed walls-deep cavity wall and exterior insulated wall using a stochastic simulation approach. The uncertainties of the input parameters including the material properties, air leakage and rain leakage rates are taken into account in stochastic modelling. The mold growth risks of the walls are evaluated based on the stochastic simulation results.

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Section: Introductionmentioning

confidence: 99%

Stochastic modelling of hygrothermal performance of highly insulated wood framed walls

Wang

2018

Building and Environment

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“…Currently, reflective thermal insulation is being used in home attics, flat and sloped roofs, and wall systems (Craven and Garber-Slaght, 2011). There are a number of thermal insulations that can be used in conjunction with reflective insulation assemblies in building envelopes.…”

Section: Introductionmentioning

confidence: 99%

Thermal performance of wall assemblies with low emissivity

Saber

2012

Journal of Building Physics

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/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1177/1744259112450419Journal of Building Physics, 36, 3, pp. 308-329, 2012-12-23 Thermal performance of wall assemblies with low emissivity Saber, Hamed H. ABSTRACTIn wall systems, airspaces can increase thermal resistance if a reflective material such as foil with low emissivity is installed in a Furred-Airspace Assembly (FAA). In this paper, the present model, hygIRC-C, was used to investigate the steady-state thermal resistance of wall assemblies that incorporate foil adhered to expanded polystyrene (EPS) foam in a furredassembly. To investigate the effect of the furring orientation, the furring was installed horizontally and vertically and compared to walls with no furring. For wall with vertical furring, the 3D version of the present model was used to capture the 3D effect of the thermal bridges. Because the foil emissivity can be affected by dust accumulation and/or water vapor condensation on the foil surface, consideration was given to investigate the effect of both varying foil emissivity and outdoor temperature on the thermal performance of the various wall specimens. Results showed that the thermal resistance (R-value) of the reference wall (no furring) is greater than the wall specimens with furring. A lso, results showed that the contribution of the FAA to the R-value of wall specimen with vertical furring is higher than that for wall specimen with horizontal furring.

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“…With regard to drying potential, several studies found that walls with vapor-open exterior insulation allowed drying to the outside at a faster rate than walls with exterior foam insulation (Maref et al, 2011;Fox et al, 2014;Trainor et al, 2016). In addition, faster drying rates were observed during spring and summer in exterior insulated walls without an interior polyethylene vapor barrier than in those with polyethylene (Craven and Garber-Slaght, 2014).…”

Section: Introductionmentioning

confidence: 96%

"Moisture monitoring of wood-frame walls with and without exterior insulation in a Midwestern U.S. cold climate"

Glass¹,

Boardman²,

Yeh³

et al. 2018

Healthy, Intelligent and Resilient Buildings and Urban Environments

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Continuous exterior insulation is becoming more common in North American above-grade walls in both retrofit applications and new construction, as a means to improve the thermal performance of wall assemblies. Although moisture performance of wood-frame wall assemblies has been studied extensively, the drying capability of wall assemblies with exterior insulation and an interior vapor retarder in cold climates is not well characterized. This study monitored the hygrothermal performance of wall assemblies with and without exterior insulation under high and low interior humidity conditions and with intentional wetting of the wood structural panel sheathing. Moisture content and temperature of standard 38 mm × 140 mm wood framing and 11 mm thick oriented strand board (OSB) sheathing were measured over a two-year period in eight different wall assemblies, each with north or south orientation, in a conditioned test structure in Madison, Wisconsin. Wall configurations differed primarily in the interior vapor retarder (kraft paper or polyethylene film) and the exterior insulation (none, expanded polystyrene, extruded polystyrene, or mineral wool). OSB sheathing was wetted in a controlled manner at three different times of year to investigate drying response. Wintertime moisture accumulation in OSB in the tested climate zone was not a concern except in the wall with no exterior insulation and interior kraft vapor retarder, though rapid drying occurred in springtime. Drying of OSB after controlled wetting events was generally faster during warm weather than cold weather; faster with exterior insulation than without during cold weather; faster with vapor-open exterior insulation than low-permeance exterior insulation during cold weather; and faster with interior kraft vapor retarder than polyethylene.

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Exterior insulation envelope retrofits in cold climates: Implications for moisture control

Cited by 18 publications

References 5 publications

Stochastic modelling of hygrothermal performance of highly insulated wood framed walls

Stochastic modelling of hygrothermal performance of highly insulated wood framed walls

Thermal performance of wall assemblies with low emissivity

"Moisture monitoring of wood-frame walls with and without exterior insulation in a Midwestern U.S. cold climate"

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