Last time, I covered some information about demolishing a house and then went wild with some rocket calculations that I hope I applied correctly. I should probably note that they also assume a single-stage rocket, not multi-stage rockets like the Saturn V or the new Atlas V. So my comparison of the ‘house rocket’ to the Saturn V was something like comparing oranges to ugli fruit – kind of related, but not really the same thing.
Also, all of that enthusiasm about giant rockets distracted me from doing a deeper dive into how you would actually demolish a house. So let’s get back to that. If you recall, it came from my son clarifying a question he’d asked by asking “How do you blowed a house up?” Last time, we established that it’s actually fairly unlikely that you would blow a house up (aka implosion), because houses usually aren’t big enough to make implosion practical. Instead, you’d be bringing in big machines and indulging in mechanical demolition.
For a look at the types of machinery that could be used, I ended up visiting ProMatcher, a sort of search engine that you can use to look for professionals in different fields. One of their subpages was Types of Demolition Equipment, which does exactly what it says it does. It describes broad categories of equipment that you might need for demolitions work. So, here we go.
First off are the demolition machines, which are the vehicles that you might see driving around the construction site. Broadly, they can be broken into trucks, loaders, excavators, and tractors – although you get some overlap on these.
- Trucks. These are, well, trucks. They include the ubiquitous dump truck and the articulated truck – imagine a dump truck or similar with a joint connecting the cab and payload. The joint lets them turn in a much tighter area, making them more maneuverable.
- Loader. This is a type of tractor with a scoop on the front, making it resemble a bulldozer – although their primary job is to scoop up or shove around loose material. They can have tracks or wheels, and may also have a rear-mounted tool (such as a backhoe or an auger).
- Tractor. This is what you’re thinking of when you hear the word “bulldozer”. They’re used in much the same way as loaders, but for bigger and less loose object. Like, say, walls. They’re also pretty much universally tracked vehicles.
- Excavators. When I was a kid, I thought these were called steam shovels. They’re tracked vehicles with a cab and an arm, and often a scoop on the end, and I don’t know any five-year-olds who don’t think they’re the coolest vehicles on earth. At least when they’re watching them.
These vehicles get the best toys, too.
- Buckets. These are the scoops on the arm of the excavator, or on the front of the loader.
- Grapples. Big robot claw hands for the arm of an excavator, and they’re used like big robot claw hands – they lift things, and they tear things apart. Like walls.
- Hammers. Vehicle mounted jackhammers. Some are designed to go on the back of a loader or tractor, and others get mounted on an excavator arm.
- Multi-processors. ProMatcher describes this tool as “an accessory that cuts, shears, and pulverizes.” After watching one in action(), I’d describe it as “big robot jaws”.
- Pulverizers. This is another entry in the “big robot jaws” category, and it appears to be primarily used to reduce large chunks of things to much smaller chunks of things. So, pretty much what it says on the box.
- Shears. ProMatcher describes this as “used for cutting steel, cable, and rebar.” Watching one in action makes me think of Fiddler crab claws.
Remember how I said that I don’t know any five-year-olds who don’t think excavators are te coolest vehicles on earth? Well, after watching those videos I am apparently still five years old myself. Because I really, really want to try my hand at one of those.
But anyway, on to the actual demolition process. Sadly, there really isn’t a single way this is done – the actual methods vary from house to house. The general steps I described yesterday still stand, of course. But the House Demolitions page of Hometown Demolitions Contractors adds the following:
- Demolish the house. This can take anywhere from a day up to several days. Home demolition generally involves a large, hydraulic excavator tearing down the house putting the unwanted house materials into the back of a truck or dumpster.
- Remove all demolition debris from the site, leaving the site clean. Typically this means removal of everything “down to the dirt”, including removal of the house’s foundation.
In other words, it’s likely you’d see an excavator, a loader, and a truck if you demolished a house. And if you get the chance to see that happen, bring the kids. I’m sure they’ll love it.
Technically, however, I haven’t answered my son’s question. After all, he asked “How do you blowed a house up?” Not “how do you demolish a house?” The simplest way is to accidentally leave the gas on, but let’s go ahead and assume that you’re attempting to do it in a controlled and deliberate fashion.
I’m probably on a watch list, now
Strangely, simply typing “how do you blow a house up” into Google doesn’t get you many step by step instructions on how to blow a house up. It gets a few videos, and a few references to Oklahoma City, and the FBI paying attention to my search history. As a result, you won’t be getting details here. I don’t need a lengthy discussion with Agents Smith.
How Building Implosions Work has a lot of useful information on this subject. Specifically, the types of explosive you would use will depend on the nature of your load-bearing columns. Concrete columns are typically get holes drilled into them that are then stuffed with trinitrotoluene (TNT, aka dynamite) or plastic explosive. The explosion shatters the column, meaning (clearly) that it is no longer bearing the load.
Steel load-bearing columns are detonated with something called cyclotrimethylenetrinitramine, also known by the less tongue-twisting name of RDX because it was developed under the name Research Department Formula X. It is a white, crystalline solid that gets mixed with stabilizers and other explosives, and it only detonates with a detonator. If you set it on fire, it just burns. It’s considered to be far more powerful than TNT – if you’re curious about just how much more powerful, let me refer you to a US Army Armament Research And Development Command Contractor Report titled TNT Equivalency of RDX – I didn’t follow much of it myself, but the charts are impressive. Implosionworld.com states that it will cut through steel at “27,000 feet per second”, though, which certainly sounds impressive.
It’s also one of the key components of C4 plastic explosives, if you’re wondering.
Whichever explosive is used, they’re detonated remotely. They’re also frequently detonated in a sequence, instead of all at once, in order to control the direction and speed of the collapse of the building. Test explosions are typically performed on one or two columns, in order to confirm the necessary amount of explosives before trying to bring the building down. Failing would be both embarrassing and terribly dangerous.
Let’s be honest here, though. If you’ve got a house you’re trying to take down, you really don’t need to implode it. And you certainly shouldn’t try to do it yourself. Hire a contractor, and let them tear it apart with the big machines.