Probabilistic Heat, Air, and Moisture Performance of Historic Wood Framed Facades to Characterize the Impacts of Environmental Change including Degradation of Components

2017 PTT Grant, Drexel University, $40,000

Abstract

This research will advance the understanding of historic buildings by assessing the hygrothermal performance of historic wood framed envelopes in the context of climate change. This will be done using probabilistic methods for heat, air and moisture (H.A.M.) analysis to assess the long‐term performance of wood framed envelopes. A key probabilistic input is weather variations due to climate change. Using climate change prediction models, such as developed by the World Climate Research Programme, and weather data morphing techniques, anticipated temperature and precipitation will be included. This research will evaluate multi‐year hygrothermal performance, cumulative degradation risks and life‐cycle cost analysis including retrofit scenarios that are unique to historic wood framed buildings. Probabilistic degradation assessment is especially important in characterizing potential for decay and mold growth in historic wood framed structures. Weather for two US cities in ASHRAE climate zones will be investigated that represent significant change in predicted climate in the next twenty years and where a significant quantity of historic wood framed buildings exist. At least three common historic wood framed envelope assemblies will be analyzed including no fewer than three potential retrofit strategies to improve performance and durability. This will result in a minimum of eighteen climate‐envelope scenarios. Monte Carlo methods will be used to sample input parameters to produce a probabilistic distribution of outcomes. Regression analysis will be used to determine regression coefficients. This will be used to create performance meta‐models which will be used in optimization analysis to determine recommended design actions for historic wood framed envelopes.

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