Recently, increases in the interest rates have revealed their adverse impact on the housing market, and nationwide construction of new homes has slowed down significantly. This current valley follows the many peaks of strong growth periods for the housing industry that lasted several years; a result of which was a significant surge on the price of land and a tremendous increase in the cost of new homes.
In the name of affordable housing and not to deprive any segments of our society from the American dream of owning their own home, higher density construction emerged as a means for reducing the price sticker for the new houses. The developers' logic was to build the houses compact and closer together, with the narrow street frontage (35 to 40 feet), facing much narrower streets (20 to 25 feet wide), which are even dead-ends in some cases.
This way the developers could build more units per acre; which would then theoretically decrease the cost of land per unit, thus lowering the cost per house and making them more affordable to the consumers. Or, at least that is their story, and by all means, they are sticking with it.
That was their public stance for these clustered design subdivisions. But as we all know, supply and demand is the name of the game in our market driven economy. Needless to say, the altruistic facade of affordability faded away as fast as the rapid pace of the construction boom. And in reality, throughout the country, the prices for the new houses continued to soar at record rates instead.
Still all across our nation, maybe even more noticeable to those of us in the Sun Belt States where land is more abundant and houses are built much further apart, there were a rash of these cluster subdivisions being constructed. These proposed cluster subdivision designs not only challenge the fire protection concepts contained in the body of the construction codes for residential dwellings; but even push the envelope for the good old fashion common sense of general community safety. After all, it is easy to figure out that on a bad fire day, lots of dry lumber piled up very close together could potentially result in much bigger fires; jeopardizing the safety of not only the occupants, but also for the responding firefighters.
In our country, the International Code Council (ICC) publishes the International Residential Code (IRC) that governs construction of one- and two-family dwellings not exceeding three stories in height. Based on the provisions in the 2003 edition of the IRC, the exterior walls of the house were not required to have fire resistive rating, if they were not closer than three feet to the property line.
Fortunately IRC eventually recognized the significant fire exposure problems, and their 2006 edition of the IRC, modified the three-foot requirement to a minimum of five feet away from the property line. So, the current edition of the code allows the exterior wall of these dwellings not to have any fire resistive rating if they are five feet or more from the property line. And if the houses are designed closer to the property line, then the exterior wall must have a one-hour fire resistive rating.
Out here in the West, these non-rated exterior walls are mostly constructed of 2-by-4 framing, with a layer of 1/2-inch gypsum board on the inside, expanded foam in the middle for insulation, chicken wire, and then finally a layer of stucco on the outside of the wall. In general, the major difference between the non-rated wall and the one-hour rated fire resistive wall is that the 1/2-inch gypsum board is little thicker and is a 5/8-inch gypsum board on the inside of the wall instead.
Remember that the one-hour fire resistive rating doesn't necessarily mean that the wall will last for one hour during actual fire. The fire resistive rating was established decades ago during the laboratory testing. An even more important fact to remember is that when the exterior wall is between three and five feet from the property line, the IRC allows for 25 percet of the one-hour fire resistive exterior wall to be unprotected openings such as windows, vents, etc.