Side with safety

The case against it isn't conclusive, but vinyl siding has figured in some recent fires. Its use deserves a closer look

In a bit of good news, residents are returning to the rebuilt Pine Knoll Townes condominium complex where 27 homes were destroyed by a dramatic, wind-whipped fire in February. And the North Raleigh townhouses are, presumably, more fire-safe than before.

Yet the dangers that large-scale fires pose to multi-family complexes -- and to single-family houses built very close together -- have not gone with the wind. A particular fire-safety issue merits a closer look.

Consider a big July 21 blaze in Edmonton, Alberta's capital. In some ways it was like the February fire in North Raleigh. Damage was put at $25 million (Canadian) when a 149-unit condo building burned. Nine neighboring two-family homes were also destroyed; 38 other two-family homes were damaged. In this case, arson was the cause.

Afterward, Edmonton fire officials said the homes were built too close together for safety. They pointed to something else as well: vinyl siding.

So did residents. According to a news report, "Ken Smy and Beth Simpson said the siding was melting as they were fleeing out the front door. 'It melted, it was like taffy falling off the house,' Smy said." Building codes, a fire official said, "haven't really kept up with changes in building and in technology."

If that sounds familiar, it's because vinyl siding was cited in the Pine Knoll fire, which began after flames on pine straw outside the units spread to the siding. Vinyl siding has figured in other fires lately in the Triangle area that also started outside the structures.

An early June blaze in Rolesville destroyed two two-story homes and damaged two others after combustible materials ignited on a porch. According to a news report, "A home on the opposite side of each suffered damage as vinyl siding singed and recoiled against the flames." In Clayton, vinyl siding on a townhouse caught fire, apparently from charcoal, and the flames burned up the side of the house and into the attic.

So, should the use of vinyl siding be restricted? The answer is not crystal-clear. Manufacturers say that although their material does melt in high heat, it's no more prone to actually catching fire than is wood. And in assessing the Pine Knoll fire, an expert's report did not call for new rules on siding. It focused instead on the dangers of pine straw close to housing units, and on the vinyl soffits (the flat panels under eaves) through which the flames had entered the attics. Now, townhouse soffits must be noncombustible.

In fact, the Pine Knoll report, by Schirmer Engineering Corp. of Charlotte, recommends that Raleigh consider applying the new eaves standard to all types of structures. It adds, "Major fires are inevitable as people continue to discard smoking materials near homes, apartments, motels, businesses, etc. Necessary protection includes construction materials and landscaping that are more fire resistant, and possibly even noncombustible."

Having gone that far, the report stops short of what might seem a logical conclusion. If vinyl soffits are unsuitable, why is vinyl siding OK?

The report's answer is that "Vinyl siding melted and exposed fire-resistant underlayment, whereas vinyl soffits melted and exposed combustible attics." The key is having fire-resistant material behind the siding.

Yes -- and no. If we're worried about fires burning through soffits into attics, it makes sense to keep the flames from getting that high on the building to begin with. And in the townhouse fires, the flames reached the eaves by burning upward from the ground on vinyl siding. If the exterior near the ground had been brick or some other non-combustible material, the result might have been different.

More and more houses are being built very close together (those involved in the Rolesville fire were less than 20 feet apart). Spreading suburbs are pushing into what's called the Wildland-Urban Interface, traditionally a hot spot for wildfires. In potentially hazardous situations, why shouldn't fire-safety rules go the extra mile?