I’ve written about the differences between timber frame, balloon frame and platform frame houses in an earlier post you can read here, but I constantly get questions about how to tell if your house has balloon framing.
Why do people want to know?
Well, of the three types of framing, balloon frame houses have the greatest danger of catastrophic fires. To be clear, there is nothing intrinsically more flammable about a balloon frame house. It wasn’t built with kindling in the walls. The problem comes down to design.
What is Balloon Framing?
Balloon framing was the most common form of construction in America from about the 1880s to the 1930s.
In the 1800s, people started looking for a way to build houses faster and more inexpensively. Unless you were a skilled housewright, most people were unable to cut the complex joinery required for a timber frame house.
At this time, dimensional lumber (2×4, 2×6 etc.) was fast becoming available along with manufactured nails, thanks to the Industrial Revolution and railroads. This new standardized group of building materials would make balloon framing possible.
A balloon frame house is built using dimensional lumber fastened with nails, not joinery like the earlier timber frames. So, how is that different from how we build houses today?
Well, what makes a balloon frame unique is that the framing members run all the way from the mud sill to the rafters. These were much longer studs than anything we use today and since there was still a wealth of tall old-growth trees in America’s forests, lumber mills could make a 20, 24, or even 30 foot long 2×4!
What’s the Problem With Balloon Framing?
In this time period, most houses were built without insulation and these long continuous studs created hundreds of perfect, unobstructed, passages for fire to spread.
You see, in a platform frame (how we build today) there is a break between each floor in the stud bay called a top plate. A balloon frame doesn’t have this break and so a fire that starts in the basement can easily (and very quickly) spread to every floor of the house.
In the days of balloon framing, house fires were all too common and most houses didn’t survive long enough for the fire departments of the day to make much difference once they did get on site. Houses would burn down very fast and often didn’t allow enough warning for the people inside to escape to safety.
By the 1930s, platform framing was seen as the solution to this fire safety issue, not to mention the fact that we were running out of extremely tall trees. It made more sense to build houses with shorter pieces of lumber since that was not only safer, but also cheaper.
How to Tell If You Have a Balloon Frame House
It’s not always easy to see what’s hiding behind the walls of your house and old house owners from the balloon frame period of 1880-1930 have a right to be concerned since there is a distinct possibility they have a balloon frame house.
The issue of not having fire breaks between floors obviously isn’t a big deal for one story houses like many Bungalows or Mission style homes, but for other multi-story houses, it’s important to know what you have.
Unless your walls are opened up, it’s difficult to tell what kind of frame your house has. The attic is usually the best place to start looking. In a balloon frame, the 2nd story subfloor is held up on the edges by a ledger board instead of resting on the top plate in a platform frame.
If you look around the edges of the 2nd story subfloor or attic subfloor in a balloon frame house, you’d be able drop a penny down to the basement in the stud bay. In a platform frame, the penny would rest right there at the break between stories.
It’s not a perfect or scientific test, but for me, that’s usually the easiest way to tell unless the walls are all opened up for some other repair.
How to Make a Balloon Frame Safer
So, you have a balloon frame house, now what? Well, you want to be extra vigilant about fires for one thing. And if you can, it’s time to add some fire blocking to your walls.
Fire blocking is the process of adding horizontal blocks of framing lumber between the studs (especially at the breaks of each story in the building.
You’ll have to remove either the interior walls or exterior siding to gain access to the stud bays to add your fire blocking, which makes the process all the more difficult. These blocks of wood stop the fire from spreading up through the building and helps to keep the fire contained (for a time) to the lower story.
Is it always necessary to add fire blocking? No, but it increases the length of time to get out of the house in case there is a fire. Just like smoke detectors and fire extinguishers, fire blocking is a good way to ensure your safety.
In the end, a balloon frame wouldn’t discourage me from buying a house, but it is definitely something to consider.
Founder & Editor-in-Chief
I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.
Hello: This is a great site for homeowners.
I hired a company to build a cabin that incorporates an 11′ balloon framed bearing wall at the entrance. The county requires a sealed design which apparently was not included in the design. What that means? Please advise. Thank you
Hi Scott,
The linked article on insulating old houses is very helpful. However, what insulation should be used is mot mentioned other than “to a minimum of an R-49”, but what kind of insulation should be used? Here’s the paragraph in question:
“There is one type of insulation you can install to prevent heat loss in your historic house. Heat loss in a house happens primarily in an upward movement, like a chimney. Therefore, you should seal and insulate your attic space to a minimum of an R-49 with eave ventilation. It’s also a good idea to seal and insulate the box sills in your basement — the area where the beams or floor joists rest on top of the foundation.”
I would greatly appreciate an answer on what type of insulation to use for basement and attic insulation where walls already exist.
Thanks!
Maria
One type of insulation I’m referring to is attic insulation. The materials isn’t as important as the location though I am a fan of mineral wool and blown-in cellulose.
Thanks so much! I thought he might have been referring to some “special” insulation, but basically where the insulation is placed is what really matters.
We have a bloom frame built in 1906. We have redone a few rooms and removed the plaster and lath then insulated and rewired each room as we go. We would like to continue doing this, money dictates how fast or slowly we progress. My questions are… Am I correct in thinking we have to rewire before we insulate, otherwise we are blocking our access? Is blown in insulation better in our case then batting insulation? Trying to decide which project would be next. Possibly instead of another room doing a full rewire and insulation to the remainder of the house as the next project. I appreciate the helpful advice on a unique situation!
Retrofaom injection (www.pridemarkllc.net) is the best non-distructive solution for thermal insulating as well as fire, bug, rodent and sound protection of ballonframend homes.
Very informative blog! Thank You
Sorry, left out the link to the article that tells why you do not want to use insulation, especially blown-in, in the old houses with plaster-over-lath walls, probably typical with balloon framing:
This article says you do not want to insulate the old plaster-over-lath walls, typical with balloon framing. Just
My ballon framing, a one story house in coastal Texas, is open to the ground under the house. The wall studs extend beyond the floor joist to a mud sill. I was told this type of framing was used to allow air flow in the exterior wood clapboard – stud – interior wood shiplap walls. Does this make since? Can wood to stud to wood walls be insulated?
Just curious if the advent of the FHA during the mid 1930s is responsible for the shift from ballon framing to platform framing.? I know that FHA standards were an impetus for heavy electrical wiring becoming standard practice in home building.
Couple of things that may have already been mentioned but come to mind.
EASY WAY TO TELL IF YOU HAVE BALLOON CONSTRUCTION (follow up with penny drop or tie a string to a nut and drop nut in stud bay)
In my experience looking at the studs from the basement I often find insulation piled up on the sill usually over flowing onto the floor. I saw someone mentioned they didn’t insulate this but I live in the Northeast and every time I have come across balloon construction this is the case.
CHEAPER KNOB AND TUBE REPLACEMENT COST
I don’t like to speak of things I am not qualified on so will limit this to my expertise although I have to believe that it applies to other trades. Where I live balloon construction and knob and tube wiring go hand in hand. Often times the cost of a full rewire has people leave knob and tube in 90 percent of their home and eliminate only per insurance company guidelines which is basement and attic. The electrical cost is substantial as is repair of the walls and ceilings that get Swiss cheese to allow for new wiring. These costs are half as much with balloon framing.
I am absolutely worthless when it comes to anything outside of electrical work and for this reason I can not comment. When it comes to a whole home rewire I can assure you that every electrical contractor prays for balloon framing.
We have a balloon framed home with a bad squirrel problem too. You had mentioned that you can add fire stops either from interior walls or by removing exterior siding. We are looking to replace our siding is it more costly to do it then or just go ahead and remove inside plaster to add fire stops.
Correctly built a balloon framed structure has many advantages. The fire hazard can be easy subdued by multiple blocking among other techniques. Using let in ledgers is superior to nailing but requires 2×6 minimum studding. It’s too bad there’s no more old growth lumber so it would be costly to build that way today but the possibilities are endless for design with balloon framing, just look at your old victorian gothic style homes.
It’s very simple to find out any matter on web as compared to
books, as I found this paragraph at this web site.
Here in Central Arkansas we needed to run some cabling in a 3 story house built in the early 1900’s. The house was turned into an office. Because it has balloon framing we were able to successfully run the cables through the walls between the stories pretty easily. Our only concern was a cross plate every so often but it was thin and easy to break through. So, another positive for balloon framing!
One advantage of ballon is that cellulose insulation drops allthe way down from the second floor and will insulate 1st floor walls. Is cellulose considered a fire retardant in the situation you described?
It may help a little bit, but fire blocking with framing lumber is really the only way to get the increased time your house needs for safety.
And for those who have added spray foam insulation in the stud cavities… take a look at this video.
I know this is an old article but the link in the last comment doesn’t work. Is there another link you can provide? I’m interested! Thanks.