CAIRNS, Australia, Oct. 13 (UPI) -- Roof design used to be rather simple and uniform. Today, houses boast an array of complex roof shapes. Recently, a pair of researchers in Australia decided to see how today's roofs measure up to building standards.
James Cook University researchers Mitchell Humphreys and Korah Parackal constructed miniature house models with a variety of roof shapes and tested their performance under different wind speed and direction combinations. The results suggest more complex designs have opened houses up to new structural vulnerabilities.
"Houses used to be square boxes, with standard shape roofs, but in recent times custom shapes have become common," Parackal said in a news release. "With the new shapes we see wind force acting in new ways on roofs."
Part of the problem is that building codes haven't kept pace with architectural complexity.
"The current building standards can underestimate suction pressures on roof edges of houses with complex roof shapes, and more so for two storey houses," Parackal said.
Strain placed on roof edges and structural joints can lead to further wind and water damage.
Another problem is architects and contractors seem to only consider a worst-case wind event from a single wind direction. Humphreys and Parackal found modern roof shapes are vulnerable to a variety of wind directions.
The researchers say homeowners aren't in immediate danger, but suggest writers of building codes take a closer look at the ways modern designs are exposing homes to severe weather damage.
"We saw a relatively new shed that had lost its cladding, simply because the builder had used a screw that was only slightly the wrong size," Parackal said. "Our wind tunnel research has shown the margins for error are not as great as many people think and underlines the need for builders and apprentices to be aware that very small defects in construction can get you in very big trouble."
Humphreys and Parackal published their findings in the Australian Journal of Structural Engineering.