Thermal Patterns Created By Moisture Accumulation Within Exterior Masonry Walls

Abstract

In cold climates, air leakage is accompanied by moisture transport. When migrating through dew point temperatures, a considerable amount of moisture accumulation may occur depending on variables such as the duration of sub-zero exterior temperatures, building pressurization, wind effects and the level of interior relative humidity. Moisture accumulation may result in premature deterioration of wall assemblies and the formation of mould. When commissioning new building envelopes, or carrying out building condition inspections of existing building envelopes, it is imperative to differentiate the source of the moisture accumulation since the recommendation for remedial action will vary considerably. This paper will define the various types of thermal patterns created by surface penetration of water versus those patterns created by air leakage from the building interior in cold winter conditions. Various types of exterior masonry building envelopes will be discussed along with their hydrothermal performance characteristics and how these affect thermal patterns during various inspection procedures.

Practical identification of moisture sources in building assemblies using infrared thermography

“…These thermal patterns could be in parallel through the assembly or adjacent to each other so as to create a patchwork effect with complex thermodynamic interplay. (Colantonio, Desroches 2005) …”