Journal of Architectural Engineering

This paper presents a new one-equation model, and case studies utilizing it, for evaluating the thermal effectiveness of slab-on-grade perimeter insulation in common wood-framed buildings for any time period such as a month, a season, or an entire year. Many previous studies focused on heat losses in very cold climates, but this new model can be effective for both heating and cooling in potentially any climate that has coefficients available. Two case studies, of residential and commercial buildings, are presented in this paper for three levels of foundation insulation and for three different, somewhat-warm to somewhat-cold, climates. Economic analyses of their heating seasons, cooling seasons, and annual performance are then presented, and the overall worthiness of the insulation, from energy cost and other perspectives, is discussed. The hand calculation method presented differs from previous efforts because it uses a new, single transient analytical equation and site-specific coefficients. The model gives designers, builders, and code officials, for example, the specific, defensible information needed to make decisions on whether insulation is needed. For the residential and commercial building examples presented at least a minimal amount of perimeter insulation is justified, both thermally and economically, for at least two of the three locations studied.

Widespread damage to tile roofs over the last few years, even for weaker hurricanes, has raised concerns regarding construction practices and codes. An experimental study was carried out for clay and concrete roof tiles with adhesive- and mortar-set attachments using a “Wall of Wind” apparatus. The estimated peak $3\text{-}\mathrm{s}$ gust wind speeds achieved in the simulations were 31.5 and $57.9\mathrm{m}∕\mathrm{s}$ (70.5 and $129.5\mathrm{mi}∕\mathrm{h}$ ), as defined by the ASCE 7 Standard. Tests were conducted for winds from the 0° direction and subsequently, unless the roofs suffered significant damage, from the 50° direction. The research objectives were to assess roof-tile performance and observe failure modes in simulated hurricane conditions, and obtain wind pressure data allowing comparisons of measured pressures with pressures for components and cladding specified in the ASCE 7-05 Standard. Comparisons of pressure time histories for different tile systems showed that the external pressure on a tile is strongly influenced by the surface geometry of the tile. The concrete tile roof with mortar set showed the best performance among all tested roofs. Workmanship was found to be a major factor to roof-tile performance. Test results also suggested that the ASCE 7-05 pressure coefficient values are conservative for assessing wind loads acting on individual tiles.