The cause of the fire that destroyed most of a house at 89 Jillian Way on May 7 is a mystery to investigators and may stay that way.
State Police investigators have eliminated ‘accidental’ causes, Deputy Fire Chief Allen Manley said Thursday, and there is no reason to think that it was deliberately set or that there was any criminal involvement.
“It appears that there were no smokers in the house … For now the cause is undetermined.”
Insurance investigators had initially pointed to an extension cord as a possible cause but Westport fire investigators found that the suspect cord had not been plugged in.
The fire started on or beneath a back-side deck and raced quickly up the side of the house to the roof. By the time the first engines arrived, just a few minutes after being alerted by a 911 call, much of the house was ablaze and the roof was minutes from collapse.
In that way, it was “remarkably similar” to a fire the previous Tuesday that destroyed a house on nearby Meadowbrook Lane. That fire, too, started near a back deck and quickly engulfed the large, relatively new house.
That first fire is believed to have started in dry mulch near a rear deck, possibly ignited by a cigarette butt.
Given the similarities, mulch was high on the list of early suspects this time too until fire investigators discovered that there was no mulch beside or below the Jillian Way deck. Instead they found stone.
The Jillian Way fire was discovered by neighbor Robert Morotti who was walking his dog when he spotted smoke coming from the back of the house. He alerted the occupants — Megan Sousa and her grandmother, Maria Sousa — and got both of them out of the house before firefighters arrived.
Deputy Chief Manley said that Mr. Morroti told investigators that shortly before he saw the smoke, he had noticed a smell like burning leaves or brush. The deck, though, was a composite (Trex brand) material with a plastic awning overhead — which would presumably smell much different when burning.
Exterior fire, new house a dangerous mix
Similarities both fires share are the facts that both started outside, both moved with extraordinary speed, and both led to quick roof failures.
“We are finding that with new construction it can almost be worse for the fire to start outside than in,” Deputy Manley said.
A fire that starts inside can be restrained initially by sheetrock barriers and closed spaces, he said.
Most new houses are built with soffit vents designed to pull outside air up through the roof structure to ridge vents.
“So what happens is that when a fire starts outside” as these did, “the heat and flame get sucked right in the soffit vent and up into the roof.”
Once inside, the flames encounter unprotected wood construction.
Today’s truss-type roof designs are also vulnerable. Often built from fairly lightweight lumber, they rely on design less than massive size for their strength. And unlike old construction in which beams were connected by long, heavy snails or spikes, these can rely on fasteners that scarcely penetrate the wood.
“My house is old and the roof rafters are 4x8s — they could burn for a long time without giving way,” Deputy Manley said. The new truss construction is very strong in almost every circumstances, he added, except fire.
“In these two cases, the roofs were gone in no time.”