For the average American fire department, dwelling fires are the most prevalent of all types of fires. Thus it would seem logical that our national fire service should concentrate on this category and at least make an effort to sharpen its performance. It's here that more lives are lost and more misery caused than with any other variety of blaze.

While it's said that no two fires are exactly alike, the dwelling fire, at least, can come close to proving that. There are various sizes of dwellings in many similar styles, and fires tend to occur in identical areas. In general we can foresee some consistency and develop a routine operation.

I've written about 1H-, 2- and 2H-story frame dwellings in the past. Following the 2-story dwelling series, I was asked to look at the 1-story frame dwelling and the consequences of fire therein. My thought at the time was that it should be the easiest class of dwelling to handle, so why bother? I have changed my mind since then because I've seen 1-story stretched dwellings that include three-car garages. Total up the cost of those vehicles, the value the structure and furnishings, and the human element of the family, and you have a package of astounding value.

The 1-story dwelling probably was the first housing in colonial America beyond some form of crude shelter, most likely the log cabin. Most log cabins that I've seen have a loft used for sleeping, so this style could be considered a 2-story, but because it was so crudely used under the eaves we consider it a 1-story building. Over time, log cabins gave way to what we know as the frame process, and multi-story structures developed.

There are two styles of 1-story frame dwellings. The basic type was common until the end of World War II and consists of a basic structure with few variations and a detached garage. The second type often is referred to as the ranch house or stretched version. This type includes an attached garage. The 1-story dwelling in its original form might have had various titles such as shotgun house, mill house or bungalow. One can consider that our subject structure had many regional and professional names. The variations over the years and over the land are numerous, so our description will not cover all styles in all locations, but it will be valid to most.

Construction basics

We will start with construction from bottom to top. The first consideration is the foundation and whether there is a basement adding another level of storage and utility space. This translates into fuel to burn and sources of fire typical to residential storage areas.

If there's not a basement, then a 2-foot crawl space might be present, and this space isn't immune to fire. Water pipes and drains in this area can freeze, tempting the occupant to use heat lamps, electrically heated tapes and wires to thaw them. In the worst and most troublesome cases, an open blow torch or propane torch is used. You have two choices to get at a fire in these spaces: Crawl in and approach it horizontally, or chop or saw your way into it from above.

The least of the foundation options from a fire origin standpoint is when the structure sits on a concrete slab. Consider, however, that the utilities and their inherent problems won't be eliminated with the lack of a crawl space or cellar. They will be included or compressed into the above-ground level, so it's generally a trade off.

Foundation options aside, the next building member to be laid is a sill, which sits on the foundation. This sill can be various sizes, but two popular options in the older buildings are 6- by 6-inch or 8- by 8-inch timbers. The wall studs sit on this sill rather than on the concrete of the foundation.

At this point floor joists go down. There are several ways to do this. They could be put directly on the sill, or notched at the ends and then put on the sill. This would allow a subfloor to be put on the floor joists, keeping the workers from accidentally falling into the basement. The wall studs then could be set and a 2- by 4-inch board, or possibly two of them, placed one on top of the other. This will tie the upright studs of the entire assembly into a rigid frame, making four walls. The ceiling joists span from one wall to the other. In the older model where the house sat on a typical narrow lot, the ceiling joists were sidewall to sidewall. In the later period when zoning laws required a wider lot, the 1-story frame dwelling sat with a broad front and the slightest dimension then became front to back. In this case the ceiling joists ran front to back, spanning the lesser dimension. When the ceiling joists are nailed into the wall assembly you have a good strong frame. Each assembly, wall stud and ceiling joist gives support to the other.

Keep in mind that certain area building codes in northern climes can call for 2- by 6-inch outside wall studs instead of 2-by 4-inch ones. This is to ensure additional insulation against weather extremes. It makes sense weatherwise, but it increases the fuel load to the total structure.

When you put into this frame interior partitions composed of 2- by 4-inch lumber, that frame becomes even more rigid. This covers everything except a peak. Rafters are angled up from the walls to join at the top by a ridge board, and we have it. The frame for four walls, a basic floor, ceiling joists and a peak are all tied into a single assembly.

How the roof was laid depends on how old the structure is. In the early ones the roof boards meet, but a gap of a few inches was left between them to be covered with wooden shingles. Modern versions feature plywood topped with asphalt shingles. A couple of decades ago this could have been rolled roofing.

Of course you must cover the walls on the outside. In most cases it's clapboards, but there were eras of asbestos shingles and asphalt rolled siding that looked like imitation brick. A brick or stone veneer is not uncommon, and vinyl siding may have been used during a renovation.

Likewise, the inside walls had to be finished off. Lath and plaster was the most common, but later came wall board and ceiling tile. Of course the place had to be plumbed and wired, and a chimney had to be added to vent the heating and cooking devices. Move in the furniture and you have a place to dwell. It's a fact that in the span of history, millions of people did that in like structures from coast to coast. It's also a fact that many fires and deaths by fire have occurred in the 1-story frame dwelling, not that it's any more hazardous than any other class of our dwelling inventory.

Combustible housing

The truth is, as a nation we build and furnish with combustibles. Apparently we prefer to accept the consequences of our choice or we would long ago have converted our building and furnishings into something with little or no flame spread.

In addition to the old type of 1-story frame dwelling that we just theoretically built, more of the modern ones without the built-in garage abound. In fact, this humble writer lives in one. It was built 25 years ago, and the construction technique and building components differed from the type built prior to World War II.

With mine the foundation is concrete block. The sill is only 2 inches thick, and 2- by 10-inch floor joists sit on the sill running side to side. The dimension is 30 feet by 40 feet. Instead of going from one wall to the other, these joists run halfway across and sit on three 2- by 10-inch boards that run front to back. These are supported on the ends by the foundation and adjustable metal columns at intervals. These and the foundation bear the weight. I think heavy and prolonged fire conditions in the cellar could weaken this assembly, causing the structure to sag or possibly cave in at the center point.

A sub floor goes on the 2- by 10-inch floor joists. Then 2- by-10s that sit on edge are used around the foundation to box this in. That gives you a platform on which the wall studs sit and rise. Once this is up and the 2-by-4s that overlap at the ends are nailed to it, you have a sturdy frame. Pre-built roof trusses running sidewall to sidewall form what turns out to be a blind attic. With all the component members of these pre-built trusses, it looks like a forest up there representing one heap of fuel if it ever combusts. The roof decking is plywood followed by asphalt shingles.

In the modern 1-story frame dwellings, the 2- by 10-inch floor joists have been replaced by I beams that have a long span and are very strong. The beams can be installed and run clear across the foundation from side to side. The top and bottom of the assembly is a wood strip, and there's a particle or flake board in the upright position to create the I configuration. These save a lot of wood joists and steel columns.

These beam replacements do a good job of giving a nice clear space in the basement, but they don't have a good reputation for resisting the heat from fire. They are made entirely of combustible components, and the particleboard is not overly thick.

So we see that while the 1-story frame dwelling is still with us and is apt to be beyond our lifetimes, it has changed in construction technique yet remains combustible. It's important that fire protection providers keep abreast of its components and peculiarities so that as we approach it in a time of crisis, it's familiar to us and we aren't acting simply out of instinct. Instead we should be able to look at it and automatically deduce procedures that will quickly curtail the ongoing catastrophe and preserve the structure for an extended existence.

Look around your fire district or response area and observe the dwellings of this type that you're responsible for protecting. How many have crawl spaces beneath, how many are on slabs and how many are there with full basements? How many have roof trusses that were put together as the house was built, and how many have pre-fabricated roof trusses? Further, are those pre-fabricated trusses glued together, or do they have gussets or gang nails?

If you don't think you want to know now, you're going to want to know when you shut off your siren, get out of your rig and watch the place being obscured by smoke. It's your job to find and extinguish a fire without your personnel or your community members suffering injury or death. Know and learn now, for the time is coming.

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Prior to his retirement, Donald L. Loeb served the Dunkirk (N.Y.) Fire Department as a volunteer firefighter, assistant chief and chief. His experience spans six decades of military and civilian firefighting, teaching, and writing.