Your Open Floor Plan is a Death Trap

We live in a neighborhood of early 20th century bungalows. Sadly, homeowners and house flippers have ruined most of these old houses by removing walls and built-in cabinets in a misguided attempt to remake the interiors into the style that just won’t die: mid century modern. While I’ve been a lone and contrarian voice on this issue, a recent story in the Washington Post tipped me off to an unintended consequence of this open floor plan trend: greatly increased fire danger both for residents and the firefighters who put out those fires. It turns out that all those old walls, doors, windows and traditional flooring materials had a purpose: they made our homes vastly safer.

How much safer? According to research by Underwriters Laboratories (“Analysis of Changing Residential Fire Dynamics and its Implications on Firefighter Operational Timeframes“), in a small, traditional house with individual rooms you’ve got almost thirty minutes to get out before a fire flashes over. In an open floor plan house you have under five minutes, which means that firefighters probably won’t even get to your house before it becomes a raging inferno.

U.L.’s research uncovered a number of alarming trends that they summed up as “larger homes + open floor plans + increased fuel loads [i.e. large sectional couches] + new construction materials = faster fire propagation, shorter time to flashover, rapid changes in fire dynamics, shorter escape times, shorter time to collapse.” It turns out that nobody was considering fire safety as trends in materials and living arrangements have changed in recent years. While the number of structure fires has stayed the same since the 2000s the death rate has increased (U.S. Fire Service Fatalities in Structure Fires 1977-2009 Rita F. Fahy, Ph.D. June 2010).

Let’s take a closer look at some of the unintended consequences of open floor plans and modern materials.

Open Floor Plans

U.L.’s research proves conclusively that open floor plan interiors create fires that spread faster and are harder for firefighters to control.

Another trend in homes is to remove walls to open up the floor plan of the home. As these walls are removed the compartmentation is lessened allowing for easier smoke and fire communication to much of the home. In the living spaces doors are often replaced with open archways creating large open spaces where there were traditionally individual rooms . . . Combining of rooms and taller ceiling heights creates large volume spaces which when involved in a fire require more water and resources to extinguish. These fires are more difficult to contain because of the lack of compartmentation. Water from a hose stream becomes increasingly more effective when steam conversion assists in extinguishment, without compartmentation this effect is reduced. The simple tactic of closing a door to confine a fire is no longer possible in newer home geometries.

Building codes for commercial spaces require a certain amount of compartmentalization. Residential codes don’t require the same level of fire prevention through compartmentalization. In the interest of fire safety, perhaps it’s time we start requiring more walls in new homes and prevent those house flippers from removing walls in old homes.

Synthetic Furniture
Another big factor in house fires has been an increased use of polyurethane foam in furniture. It turns out that foam is more dangerous than the cotton it replaced. I will add that fire spreads faster in particleboard, plywood and MDF than in hardwood (see Flame Spread Performance of Wood Products). All reasons not to pick up that cheap mid-century crap at Ikea! Add the factor of the clutter we all have (also made mostly of synthetic materials) and you’ve got a recipe for tragedy.

Building Materials
The U.L. report goes on to note the superior fire retardant characteristics of traditional lath and plaster over modern drywall.

As drywall compound is heated it dries and falls out exposing a gap for heat to enter the wall space and ignite the paper on the back of the wallboard and the wood studs used to construct the walls. Gypsum wallboard also shrinks when heated to allow gaps around the edges of the wallboard. Plaster and lath does not have the seams that wallboard has and therefore does not allow for heat penetration as early in the fire. This change in lining material allows for easier transition from content fire to structure fire as the fire has a path into void spaces.

Too bad that hardly anyone knows how to do lath and plaster work anymore.

Traditional windows also vastly outperformed modern windows when it comes to fire safety.

The legacy window glass was held in place with putty like substance and there was room in the frame for expansion of the glass. The modern glass was fixed very tightly into the frame with an air tight gasket and metal band, to provide better thermal insulation. This configuration did not allow for much expansion and therefore stressed the glass as it heated and expanded.

Home Size
Small and tiny house proponents will be happy to hear that small is better when it comes to fire safety. The bigger the home the bigger the fire. And the increase in two story homes means fewer paths for egress and more danger for firefighters.

The stark truth is that a small, old house with traditional furniture is a lot safer than a modern open floor plan home with clutter and big couches. House flippers should think twice before ripping out that nice old lath and plaster wall.

Leave a comment


  1. I wonder how open floor plan houses built with natural materials (cob, strawbale, clay straw, etc) fare in fire conditions.

    • Probably a lot better. You would still need to think about the roofing material, which is usually wood.

  2. My house is huge, 400 sq ft, mostly is a horrid state of disrepair. I have always wished to have the plaster and lathe board ripped out to insulate the walls. Now, I see this would be folly. I do have two rooms of sheetrock. My plan in case of a fire has been to close doors, obviously, I can. With about 15 doors between rooms, I can see how isolating the fire would be possible.

    By the way, I, too, hate open plans. When anyone does anything here, I have to fight to keep everything wood without plywood or pressed wood or whatever that nasty stuff is. I see tiny homes built of pressed wood and plywood and think of them as fire traps and places with poisonous glue off-gassing.

    I have a chair that needs upholstering. Now, I will have the upholsterer use cotton and wool, especially wool.

    • Keep that lath and plaster! And from what I understand, attic insulation is a lot more important than wall insulation.

  3. Wow. That was fascinating. And alarming–especially the video with the synthetic furniture vs natural. Holy smokes! I’m going to wander around the house taking it all in from a totally different angle today.

    • My reaction too. It’s really interesting to see architecture from the perspective of a firefighter.

  4. I knew that my love of quirky, old, cantankerous houses was justifiable! In the last few months my interest in the process of doing lath and plaster has been sparked–largely because plaster walls can be so incredibly beautiful. I’d like to learn how, beginning with some small projects around my house (mostly repairing the existing plaster walls) and possibly ending with re-plastering my kitchen. Do you have any recommendations of books on the subject?

    • I took an earth plastering class taught by Kurt Gardella (who also built the earth oven in our backyard). It was a three day workshop and Kurt is a great teacher. I don’t know where you live but his classes are worth the trip to New Mexico. You can find him at:

  5. Hmmm….short of selling our homes, what would you suggest to the poor loser who spent their last dimes getting into the market, only to find themselves shacked up in said firetrap? Plaster the couch?

    • I’d make sure that you have a fire extinguisher and know how to use it and know that you have minutes to get out in the case of a fire.

  6. well that makes me glad that we were too lazy/cheap to remove walls when we renovated! And all our walls are the original hardwood VJ. I had never thought about the fire risk before.

  7. Wow! This is great info. I never liked all those new model homes with the open floor plans. I could ever understand why someone one would want to be able to look into the kitchen while the host/hostess cooked. And I don’t want to be bothered when I cook unless they are willing to help, not yak and distract me. Having a kitchen where you can close the door on all the dirty dishes and relax with friends afterwards is what I like. I don’t want the company feeling like they have to get in and help clean up which is the case if they are sitting somewhere that they can see you working. OK that is my rant for the day. I am glad I have latch and plaster walls, small rooms, and old furniture that dates from early last century. I will never complain again about being outdated!

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    • most likely cause of drop in residential fires is fewer people smoking — and falling asleep with a lit cigarette in their hand. Also fewer kitchen fires because so many people don’t cook. Zapping carryout is less likely to cause a fire than frying on the stove.

    • While overall fatalities may be down, the question that the UL research is, in part, trying to answer is why the rate of firefighter deaths has gone up since the mid-2000s.

    • A lot of things are responsible for drops in fire deaths. SMoke detectors in the majority of homes, sprinkler systems, drop in smoking, updates in electrical codes and safer appliances.

  9. I’m not really sure why, but this post bothered (irritated) me. I felt like you were criticizing my preferences rather than just presenting the facts (which seem to be in question too, based on the comment above). I like open floor plans. I like being able to talk to people in the living room area while I’m cooking or doing dishes. I don’t want to be trapped in a small confining kitchen by myself while family or guests are somewhere else. And people like to hang out in the kitchen and talk to the chef. I don’t want a rabbit warren of doors and hallways. I feel like I can have a smaller house with an open floor plan without feeling closed in. And I do have a fire extinguisher as everyone should, regardless of floor plan.

  10. Hmmm:

    Don’t know what to think about this. Plaster and lathe had a real problem in that once a fire got into the walls it would spread through the hollow, “balloon wall” through the house. Having ripped out plaster and lathe, I can attest that lathe in old houses is just about the best kindling I’ve ever seen.

    I do take the synthetic materials to heart. But aren’t they made with fire retardant? Is this an intrinsic problem, or, the result of stupid deregulation?

    Finally, as for not recommending insulation. Obviously the author doesn’t live where I do.

  11. Thanks for the article. Its an interesting perspective. I live in a lathe and plaster baloon frame home and the first thing we did to make it “fire safe” was to insuate it with wool bats pushed down through the balloon frame from the attic. A lot of work, but way quieter, warmer and fire can spread less easily up the walls now!

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