Several Napa cities have made great strides over the past five or six years as homeowners embrace the concepts of defensible space around their houses.

There is another area that we can all address: Just how fire resistant are our homes themselves? And how can we improve the survivability of these structures in a wild fire?

Most of our homes are around 20 years old - the tender age when things start to need replacing. 

Several parts of the home might fall into this category, and as you consider repair or replacement, there are many innovations in building technology and materials.

Roofing

Your home’s strongest line of defense is the roof. Most fire-resistant Class A roofs are made of aluminum, asphalt, steel, concrete, clay or slate. Such a roof is especially protective in a foliage-borne fire that rains hot embers. Treated wood shake looks good but provides the least protection in a raging fire that falls from above. Keep the design of your roof uncomplicated using a simple hip or straight gable roof. Roofs with intersecting planes and valleys are architecturally smart looking, but they form dead air pockets and eddy currents that help fan the flames of a fire.

Exteriors

Stucco, stone, masonry and other exterior materials are better than wood at preventing fire from intruding into the walls. They are the most expensive materials, but they give walls a two-hour rating. Metal siding also provides greater fire protection, but you must take measures to reduce a wicking effect that can allow condensation to develop and deteriorate material behind the siding. Also, while the metal itself is non-combustible, it needs a gypsum sheathing to give it a one-hour rating.

Windows

During many California wild fires, the exterior panes of some energy-efficient, dual-glazed windows cracked, but the interior pane held. Consider upgrading old windows with newer dual or triple-glazed windows.

Tempered glass, which costs 50 percent more than regular glass, is even more resistant to high heat. It’s the glass used in patio doors and in front of fireplaces, for good reason. Tempered glass will stay in place and intact throughout many fires.

Add low emissivity (Low-E) coating and your glass is even more fire resistant. Low-E film will reflect infrared and ultra violet light — heat rays. In a wildland fire it helps stop the radiant energy transfer to combustible materials that are behind the glass such as drapes or wood furniture and walls. Tempered glass with Low-E coating will stay intact and will transfer less radiant energy to combustibles behind it.

Unfortunately, the most popular PVC window casements are not the best choice for homes in fire country. In extreme heat, the casement can melt, fall out and leave a huge entrance into the interior of the home. If you are replacing your windows, consider aluminum or aluminum-sheathed timber windows. These also come with all the advantages of dual or triple paining.

Another option is to replace fiberglass mesh screens with aluminum ones.

Shutters

Real shutters that swing into play, not decorative shutters, can add another 10 to 20 minutes of protection to a window — all that may be necessary for a window to survive a fire. Metal shutters can protect a window even longer and they will not ignite. You will, however, have to swing them shut, should a fire approach.

Doors

Like roofing materials, doors are also fire-rated. Solid wood doors are stronger than hollow ones. Metal doors are best. In any case, a good fire resistant door requires adequate weather stripping so that the seal prevents hot gasses or burning embers from entering the building.

The use of metals only sounds like battening down the hatch. You don’t always have to give up form for function. Metal materials can be embossed and designed to look like wood.

Decks

In the 1991 Oakland hills fire, flames snaked beneath decks, eaves and crawl spaces.  Decks are common in panoramic regions, but the irony is that the panorama is often towering and explosive evergreens.

Most decks are highly combustible structures. They trap heat and hot gasses and they often face downhill, which is typically the direction of a fire’s approach.  Decks effectively and openly invite the fire into the home.

Most decks are built to burn perfectly, much like the way you would stack wood in a fireplace. Adding fuel to the fire, the components of a deck, joists, decking and railings, are made of only two-inch-thick wood giving the structure the high surface-to-volume ratio fires quickly devour.

Keep a deck built with fire resistant materials and create barriers by closing in the deck and crawl spaces to ward off burning embers. You can also isolate the deck from the fuels and fire by building a noncombustible patio and wall below it. The patio prevents combustible materials from getting below the deck. The wall helps shield the deck from both the radiant and convective energy of the fire.

Vents:  One area seldom considered in refurbishment are vents. Virtually all attics, soffits and foundations have vents to allow circulation of air to prevent molds and mildew. They also prevent intrusion by varmints. Given the age of most of our homes, the screening in these vents has potentially already failed, and due to old design,  they may have absolutely no value in preventing the intrusion of wind-blown embers or firebrands. 

In researching the causes of structure failures after fire episodes, it has become obvious that an alarming number of structure fires are caused by embers intruding into the house through inadequate vents, starting attic fires and causing homes to burn from the inside-out. 

One of the most promising new products are all-metal baffled vents that virtually prohibit the entrance of wind blown firebrands.

Replacing the vents is not a major expense, but it will provide an incalculable additional amount of fire safety.