Wildfire-Resistant Siding for Boulder Homes

Living close to open space is one of the best things about Boulder, and it is also why wildfire is on so many homeowners' minds. The Marshall Fire in December 2021 destroyed more than a thousand homes in Boulder County, most of them in suburban neighborhoods that few people thought of as wildfire country. Since then, we have seen a steady rise in questions about how siding affects a home's risk. In this post, we explain how homes actually catch fire, how common siding materials compare, and what else matters around the outside of the house. Our Residential Siding Services team is happy to walk your home with you.

How Homes Catch Fire

Most homes lost to wildfire are not ignited by a wall of flame. They are ignited by embers: burning debris carried ahead of the fire by wind, sometimes for long distances. Embers land in corners, on decks, in gutters and in mulch against the house, and if anything there can burn, the fire spreads to the siding and then into the walls or attic. That is why fire safety experts focus on the home ignition zone, and especially the first five feet out from the house.

How Siding Materials Compare

• Fiber cement does not burn and holds up well to ember exposure and radiant heat. It is one of the most popular choices for fire-conscious homeowners in Boulder.
• Stucco, brick and stone veneer are noncombustible and perform well, provided the openings, vents and joints are detailed properly.
• Metal siding will not ignite, though it conducts heat, so what sits behind it matters.
• Vinyl siding does not burn easily on its own, but it softens and melts at relatively low temperatures, which can expose the wall sheathing behind it.
• Untreated wood siding is combustible. Fire-retardant-treated wood products are available and improve its performance.

For a wider look at materials, including cost and durability, see our post on the best siding materials for Boulder's climate and our guide to eco-friendly siding options in Boulder.

The Details Matter as Much as the Material

Even the best siding can be undermined by details. The bottom of the siding should sit well above the soil and mulch rather than touching it. Gaps at corners and trim should be sealed so embers cannot lodge in them. Attic and foundation vents should be covered with fine metal mesh, and wood fences or decks should not attach directly to the siding without a noncombustible break. These are the details our Siding Installation Services crews pay attention to on every job.

Rules and Programs in Boulder County

Building requirements for ignition resistance have been tightened in parts of the region since the Marshall Fire, and what applies depends on where your home is and the scope of your project, so check with the building department before you plan a re-side. Boulder County's Wildfire Partners program offers home assessments and mitigation guidance for eligible homeowners, and it is a good place to start if you want a professional view of your whole property.

If your home backs onto open space in areas like North Boulder, Wonderland Hills or Table Mesa, siding is one of the most effective upgrades you can make. Our post on siding installation costs in Boulder explains what drives the price.

At Boulder Siding Group, we help homeowners choose siding that looks right for their home and holds up to the risks that come with living on the Front Range. Call us at (720) 799-0253 to schedule a consultation, whether you are in Baseline, East Boulder or anywhere else in the city.