Journal of Architectural Engineering

The objective of this study was to compare structural load path and system behavior of a light-frame (LF) and a timber frame (TF) structure. This load path analysis is part of a broader research effort that compares LF to TF residential structures. Structural analysis software was used to create a model of each structure. The TF structure was composed of large-dimension timbers and structural insulated panels (SIPs). An equivalent LF structure was designed for comparison, following the guidelines of the International Residential Code. Results show that TF outperforms LF in resisting uplift, as well as in story drift. TF also provides load paths that are more resistant to the introduction of large openings and the loss of a central post. Observed axial loads in TF posts show smaller ranges compared with LF studs.

Widespread damage to residential roofing systems during Hurricane Andrew in 1992 highlighted the structural inadequacy of wood roof sheathing attachment in existing Florida homes. Prior research found that retrofitting wood decks with closed-cell spray-applied polyurethane foam (ccSPF) could provide adequate wind resistance to pre-1994 roofs. However, it is unknown whether this retrofit method increases the potential for moisture to accumulate in the roof sheathing, and if so, what effect this has on the strength of the bond between the ccSPF and the wood substrate. Five full-scale roofs were subjected to natural weathering for 3 months, and 131 small-scale laboratory samples of ccSPF bonded to wood sheathing were intermittently sprayed with water and stored in a high-humidity environment for up to 16 weeks. These tests enabled systematic assessment of the effects of water leakage on ccSPF-retrofitted roof structures. The attic roofs were retrofitted with two ccSPF configurations and covered with three-tab asphalt-shingle roofing subjected to extreme leakage conditions. A control attic roof was not retrofitted with ccSPF. Moisture content and temperature were continuously monitored in the wood truss members of the roofs over 3 months of exposure to both natural and simulated rainfall conditions. At the conclusion of the exposure period, sheathing panels were harvested and subjected to wind uplift structural tests. Tensile tests were conducted on the small-scale samples after 0, 1, 2, 4, 8, 12, and 16 weeks of exposure. The results demonstrated that with extreme leakage conditions, ccSPF-retrofitted roofs experienced significant moisture buildup in the wood substrates. However, the ccSPF-retrofitted sheathing panels maintained high wind uplift failure capacities. The tensile tests on small-scale samples demonstrated as much as 54% reduction in tensile strength of the wood-ccSPF bond with time as a result of moisture-induced bond degradation, although the strength of this bond after 16-week exposure remained above design wind pressures by a minimum factor of 3.75.

Hurricane wind–induced damage to the roofs of residential buildings has raised concerns regarding design provisions and construction practices. Current code provisions on wind loads on roofs are mainly based on testing of building models that do not include the architectural details of roofing materials. Past research has indicated that net pressures on roof tiles can differ significantly from external pressures on bare roofs and depend on wind direction, the location of the tile, and whether the eaves are sealed. This study presents experimental pressure measurements that confirm existing findings and provide more extensive results on wind loads on high-profile roof tiles. Four different roof models with bare and tiled roof decks were tested. Pressures on the external surfaces of the tiles, within the cavity space, and in the joint space between two overlapping tiles were measured to evaluate their effects on the net peak pressures on the tiles. Area-averaged peak pressure coefficients obtained for bare and tiled roof decks were found to differ significantly. To develop vulnerability curves pertaining to roof tile damage in residential buildings, the test results were complemented by additional pressure data obtained in a wind tunnel and tile resistance data obtained from static uplift tests. The vulnerability study showed that applying the net wind uplift loading on tiles rather than external surface pressures only resulted in increased roof tile damage. Results are expected to differ for tile shapes not considered in this study. The test protocols presented in this study may be used to help develop tile-specific design guidelines.

Damage assessment surveys performed following the 2004 and 2008 hurricane seasons indicate that the vulnerability of shingle roofs to wind-induced damage increases with age. This paper presents two interrelated experiments on the wind uplift resistance of asphalt shingle seals. The objective is to identify whether and to what extent aging reduces the wind uplift capacity. In the first experiment, asphalt shingles were artificially aged, and the mechanical uplift resistance was measured at discrete intervals. In the second experiment, mechanical uplift tests were performed in situ on $\ge 9\text{-year-old}$ shingle roofs installed on four central Florida homes. Results from the first experiment demonstrate that heat exposure can reduce uplift resistance along its sealant strip in some products; however, the excess capacity in the bond may be sufficiently large to prevent the mechanical resistance from dropping below the design requirement. Inclusion of ultraviolet and water in the heat-exposure tests did not appreciably change these outcomes. Results from the second experiment, which assessed in-service roofs on single-family homes, support this finding. Overall, the results suggest that aging of the sealant strip may play a secondary role in increasing the vulnerability of shingle roof systems to wind over time. Results from a companion project performed concurrently to this one strongly demonstrated that progressive unsealing (not loss of strength) is a culprit. Improving shingle design to prevent or halt unsealing, without degrading the capacity of the sealant, appears to be the most promising solution to reducing roof cover damage.

Residential buildings are mostly sensitive to climatic conditions; building envelopes work as the interface between indoor and outdoor environments, preventing heat gain in the summer and heat loss in the winter. Proper use of energy storage technologies may reduce greatly the energy needs in residential dwellings while delivering better indoor environment quality. This paper provides a brief review of several energy storage technologies, both active and passive, for residential building applications. Particular attention is paid to the usage of phase change materials (PCMs), which have been studied for a few decades with a recent growing interest. Modeling methods of PCM-embedded wall systems are reviewed comparatively and a new simulation program is developed that can simulate the thermal and energy performance of PCM-embedded walls and buildings in a more stable and fast manner. The paper also presents a case study that integrates PCM with the traditional kang heating system for the residential dwellings in northeastern rural China. Both technical and economic performances of the solution are explored.

This paper presents an overview of the most current topics of interest related to the field of housing and residential building construction. It addresses issues related to industry-wide residential construction trends, policies, innovative technology adoption, construction management, sustainability, energy efficiency, building science, and the need for education, especially regarding architectural concerns. The authors discuss several key technical aspects of residential building, such as structural concerns, building enclosures, and indoor environmental quality issues. Emphasis is placed on the need for renewed research and development efforts, outside-the-box thinking related to financial and investment structures for housing, improved models for adopting innovative technologies in residential construction, new construction management approaches, incorporation of more advanced building science in conjunction with advanced engineered features and architectural design, embracing green and sustainable design and construction, and consideration of the health of the occupants. The authors, who have varying specialties, identify critical issues that need more investment to support technical studies and developments as well as education, training, and awareness efforts.