A house fully clad in timber and designed using Passive House principles is one of the few sparred as wildfires continue to wreak havoc in Los Angeles. That is according to Greg Chasen, the architect behind the Pacific Palisades house, who said the good fortune of the house—surrounded by houses now burnt to the ground—was partly due to “design choices” during construction.
“No words, really—just a horror show. Some of the design choices we made here helped. But we were also very lucky,” Mr Chasen wrote on the account @ChasenGreg, who reflected on the fire that has now destroyed more than 5,300 houses in the Pacific Palisades neighbourhood – making it the most destructive in Los Angeles history.
On X, Mr Chasen said that the home’s features—including a solid concrete perimeter and tempered glass windows—were among the reasons it wasn’t destroyed: “Also, there were no vents or eaves and tempered glass windows. Luckily, there was a bit more space from the neighbours—but unlucky that the neighbour pulled his car into the driveway. The solid concrete perimeter wall probably saved us there.”
According to NBC Los Angeles, the home, located on Iliff Street, was all that remained standing, while every other property on the street was completely destroyed. The home’s owner, Chris, told the station that his family has owned the property since 1998, but they recently rebuilt it and moved back about six months ago. “I’m kind of in shock and feel terrible for the neighbours,” the homeowner told NBC Los Angeles.
“We’ve just rebuilt the house, but we’ve been with those neighbours for that whole time, for almost 30 years, and seeing that devastation on the block is terrible.”
How Passive houses outlast extreme wildfires…
According to users on the Reddit subgroup Damnthatsinteresting – which now has more than 48,000 upvotes and 3,700 comments, using Passive House design principles ensured a thermal bridge between the internal and external timber frames: “The issue is that wood is often used for the envelope with no insulation to cut off the thermal bridging,” a user said. “With Passive House standards, you’re breaking the normal application of wood in the wall by ensuring the exterior wall frame is not in contact with the interior wall frame.”
“While the house looks to be made from combustible cladding,” another user said, “the extreme insulation…allows it to last a little longer during extreme heat. If a house built to normal codes would take half an hour to catch fire during this wildfire, a house built to passive standards might last a few hours under the same conditions before catching fire (allowing enough time for fire to pass by the house before burning to the ground).”
That’s because “Passive houses reduce or eliminate complex exterior geometrics, allowing firebrands to blow past the structure rather than lodge in the corners, crevices and complex roof valleys,” a third user added. “Densely Packed, fire-resistant insulation like mineral wood board won’t catch fire, (leaving) no oxygen/air gap that flames can penetrate.
As for the cost and scalability: “Passive house construction adds about 15% to the construction cost,” a further user said. “It’s meaningful, but it doesn’t put it into only rich person territory.”
“The problem is signalling to the consumer that it’s worth it. When 99% of people buy a house, they don’t have any information on how well it is insulated (past code compliance), how carefully the builders taped the seams for airtightness…and even if they did have this information, how would they know they could trust it?”
