A Sealant Story

How caulk became a standard household building and maintenance staple. If you own a house, you probably have a caulking gun lying around.

By David Buck

Today in Tedium: An interest in home improvement is just something that seems to sneak up on you without warning sometime in your 30s. I don’t know when old Popular Mechanics issues and reruns of This Old House became a personal point of fascination, but it happened. There was a time when repainting or doing a repair was something I didn’t even think about much at all. Nowadays, I’m enthusiastic about painting, caulking, and cutting tree branches. I own a flannel shirt. I have my own forestry hat and overalls. It’s weird. Last year, we explored the history and origins of WD-40—a highly versatile compound with a surprising history—and how it imprinted itself into our minds. Earlier this year, we talked about pressure washers. And as we move into the winter time—and my voice suddenly starts taking on a New England inflection—it’s time to open the home improvement toolbox again to discuss caulk. What is it? Where did it come from? And what makes it such a compelling topic? In today’s Tedium, we seek to answer these questions and seal the leak in your knowledge about this fascinating substance. Insert your best caulk joke here. - David @ Tedium

Today’s GIF is a reference to caulking in the music video for Weird Al Yankovic’s “Handy.”

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The approximate amount of hours for caulks and sealants to fully cure. Many types of caulk will set in after only a few hours, but they won’t work their magic until a day after application. Acrylic latex caulks allow for painting after two hours, but they won’t work until a day or so after application. Fully cured caulk will last longer and offer better results, so patience is necessary to make the most of this wondrous compound.

Caulking Example


Caulk as we know it is a relatively new thing

Everyone needs to use caulking once in a while. Sometimes, your bathtub or toilet needs to be re-caulked. Occasionally, you need to reseal your windows. You may want to reinforce your house’s integrity by sealing any potential gaps and cracks. It’s just part of being a homeowner. There’s also a type of caulk for every occasion. Acrylic, latex, silicone, rubber, and polyurethane are all used to make caulk and sealant—and each one has specific and optimal uses.

(Editor’s note: Ask me about the time I re-caulked the baseboards throughout my entire house.)

But what is caulk, exactly? Caulk combines acrylic and latex to create an elastic, versatile compound. People use it for all sorts of construction projects. It’s multifaceted and pretty awesome. Plus, it’s fun to use a caulking gun.

Sealant is similar to caulk but made from silicone. That’s fine, of course. Of course, plenty of people use the terms interchangeably. We don’t like to be pedantic around here, just tedious.

In a 1974 issue of Popular Mechanics, an article called “How and What To Caulk” discusses the benefits of caulking your house to stave off the high fuel costs currently affecting the country. It also talks about butyl and oil-based caulks being the cheapest and best options for specific tasks (around brick, air conditioners, and piping). But they go all in on acrylic latex for windows, cracks, and siding. Butyl rubber caulk is still suitable for many tasks—sealing gutters and other exterior surfaces—but acrylic latex is probably the cheapest option these days.

When you really stop to think about it, caulk sort of seems like magic. It’s a small bead of material that seals, adheres, and makes whatever it touches better.

So, how did this unassuming chemical compound become such an integral part of carpentry, DIY, and construction projects everywhere?

Caulk Gun

A caulking gun. (alykat/Flickr)

It all starts with shipbuilding and boiler making. Caulk—in one form or another—has actually been around for centuries. Whether it’s bits of cotton or hemp soaked in pine tar or a different blend of materials, caulk kept ships together for most of history. After all, a good seal is essential whenever water is involved. So it makes perfect sense that modern caulk has its roots in maritime construction, sailing, and shipbuilding. People would use the first caulking materials to seal barrel seams and gaps on ship decks, sealing (or corking) the outer hull of ships, and seal the gaps between planks on wooden ships. Later, caulking was used to help keep iron ships together as well. This version of caulking was a lot more physical. It meant forcing the edge of an outer riveted plate together to an inside plate to create a water-tight seal. Used in conjunction with welding, it would have the same effect as caulking/corking the seams on a wooden ship—but without the need for caulking material.

But the predecessor to modern caulk came around in the 19th century when synthetic materials started to be used for caulking. These materials—rubber, plastic, and latex-based sealants—are still widely used today. In the 20th century, more advanced caulking materials emerged, transforming how we sealed gaps forever. They were applied with putty knives and other tools by hand. But the invention of the caulking gun changed things forever, ultimately making caulking more accessible to the masses.


The year British Columbia-based inventor Theodore Witte invented the caulking gun. Allegedly inspired by a cake decorator, Witte’s caulking gun was deceptively simple. Per the original patent, Witte’s intent with the device was “to produce a simple and inexpensive tool in which a quantity of mixed putty, either hard or soft, may be carried and by which the putty may be suently and rapidly applied without the use of a knife and without the necessity of touching the putty with the fingers.” The idea certainly caught on and was eventually refined (and even expanded) over the next century or so.

Caulk Gun Design Witte

Theodore Witte’s original caulk gun design. (Google Patents)

Getting inventive with caulk

Since its initial invention, many inventors have spent a shockingly large amount of time thinking about caulk (sorry). Pursuing a better caulking gun eventually turned into multiple handy innovations that simply make caulking large areas much more accessible. Nowadays, plenty of different types of caulking guns are available to anyone.

Witte’s original caulking gun design was elegant and straightforward, spawning countless imitators and improvements over time. It eventually led to the standard caulking guns we use today—and an array of power tool versions.

Air and electric-powered caulking guns are suited for commercial building and maintenance, but nothing beats using such a convenient tool for repairs and maintenance on one’s own home. It’s easy enough to buy an electric caulking gun

And why not? The beauty of an electric caulking gun is the even flow of sealant and the ease of use it can provide for large-scale projects.

But before cordless electric caulking guns, there were plenty of distinctive ideas patented throughout the 20th century.

Take gas-powered caulking guns for example. The idea of a compressed gas-powered caulking gun is pretty compelling when you stop to think about it. There are patents for them as early as the 1950s. In this 1982 patent from inventor Glenn H. Mackal, the device is essentially just a caulking gun modified (er, adapted) to use a gas-containing capsule to operate the mechanism that pushes the caulk through the tube.

It uses the pressure from the CO2 cartridge (not entirely unlike this video of a CO2 capsule being crushed by a hydraulic press. Pretty cool, huh?) to propel the caulking mechanism. The idea was to reduce the pressure it usually takes to apply sealant with a standard caulking gun. OEM manufacturers the Halkey Roberts Association, who eventually let the patent expire in 2002.

A 1988 patent for a dual barrel caulking gun demonstrates the effectiveness of such a simple tool in combining both parts of a two-part epoxy or sealant.

This one has two barrels, designed for combining two materials in the nozzle. Originally patented by Franz K. Schneider, Jr.Michael V. Haubert, in 1978. The patent is now assigned to a company called Albion Engineering.

I saw Tom Silva demonstrate on This Old House, in an episode about using epoxy and wood filler to repair rotting wood. It’s ideal for two-part sealants and epoxy!

There have been patents for heated caulking guns and even patents for dispensing guns containing thumb locks.

But the innovation didn’t stop there. One inventor, Peter J.Y. Chang, filed several patents between 1976 - 2004.

Suffice it to say Peter spent a great deal of time thinking about caulk. Among his many caulk dispensing gun innovations include a trigger grip to reduce wear on the caulking gun, stabilizing plates for dual barrel guns, a multipurpose caulking gun (with storage caps and a cutting tool), and, well, far too many to list here.

Today, it’s easy to buy a caulking gun for a few bucks. Powered and cordless versions obviously run a little higher. But the caulking gun is still constantly being refined. Recently, the Dripless company out of California developed a gun that miraculously prevents caulk from dripping or leaking while awaiting application.

Whether it works or not, I don’t know—I don’t own one (yet)—but it’s a cool idea nonetheless and just goes to show there’s always room to enhance the tools we use every day.


The number of ounces in a standardized tube of caulking or sealant for home use. It’s also the size that fits most caulking guns. Although it’s also available as ropes and putty, these tubes are the most common form of caulk and sealant available. For heavy-duty construction and larger jobs, 29 oz tubes—and larger caulking guns—are also widely available.

DAP Caulking logo

DAP has emerged into being the 800-pound gorilla of the very specific art of caulking. (via Internet Archive)

Let’s talk about DAP

GE. Sherwin Williams. Liquid Nails. 3M. The list of caulk manufacturers goes on and on. Although Liquid Nails (we should note that LN is more of a construction adhesive brand, not strictly caulking) makes a pretty solid product, there’s one company that always seems to catch my eye: DAP. It could be their penchant for offering many distinct products. Perhaps it’s their easy-to-remember name. Either way, DAP is a powerhouse in the caulking/sealant world.

Short for the Dicks-Armstrong-Pontius Corporation, DAP came from humble beginnings making wax seals in 1865. The company was started by two men, Robert H Dicks and Elmer Wiggim.

Dicks and Wiggim started out making sealant for food canning. They worked out of Robert’s garage. Why canning? There wasn’t any refrigeration or prepared foods (source) at the time. It made perfect sense and filled a market gap. Robert bought out Elmer in 1906 and partnered with George Pontius. This created the Dicks-Pontius company in 1913. Robert died and his son, John, took over. At this point, they began selling caulk and putty. 1957 brought a merger with the Armstrong company, leading to the creation of DAP. In 1964, DAP led the way in the development of latex caulking compounds. In 1970, they came up with acrylic latex caulk (a new formula intended for windows, door frames, etc). I found four bottles of the stuff from 1992 in my garage last week. It’s called “DAP Painter’s caulk

The 1940s and 1950s brought changes to the way buildings were constructed. That also brought a change in the materials required for construction. So, DAP adapted and filled the gaps (sorry) appropriately. DAP often made its way into the pages of Popular Mechanics, occasionally even turning their print ads into mini-tutorials.

The 1980s brought silicone latex caulk, which is pretty awesome stuff. Silicone use was expanding in many industries at the time, so it was only a matter of time before it would be applied to manufacturing construction materials. Silicone caulk forms a tight and flexible seal. Plus, you can paint it to blend in with whatever surface you’re sealing within two hours. Who wouldn’t want that?

Although one could argue there’s a home repair/DIY revolution happening right now, it’s always been a popular subject. DIY magazines like Popular Mechanics bring this point home adequately (and have been for over 50 years). The do-it-yourself movement didn’t really take off until the early 1900s. That’s when some of our favorite publications—Popular Mechanics and Popular Science—started offering tips and plans for devices people could build at home to help them save some labor. As more people moved from farm work to more industrial roles, the DIY/handyman spirit went with them and grew. Today, it seems as if everyone has some sense of DIY spirit, with everything from magazines to entire YouTube channels dedicated to DIY and home improvement.

The brand did a lot more than this, and a much more comprehensive history of DAP is available on its website, but one thing remains clear: DAP is a major player in the sealant game and is a force to be reckoned with.

Here’s a commercial for caulk, because such a thing exists.

Next time you’re at a Home Depot, take a trip down the caulk/sealant aisle. Everywhere you turn, you’ll come across DAP. DAP—at this point, one of the world’s leading caulk/adhesive brands/spackle/wood filler manufacturers—is essentially a staple of the caulking arts. You’ll be surprised at how many useful products are available from DAP to make your home repairs a breeze.

DAP also makes one of my personal favorite repair/patching products: plastic wood, which has worked quite well for me in the past. DAP continues to be a leading name in the caulk/sealant world. And they’ll probably continue to innovate in that space well into the future. The sealants market is always growing and who knows what they’ll come up with next? It’ll be interesting to find out.


The official tip line for learning how to use DAP products, troubleshooting, or asking for advice from the company’s resident expert. It’s been around since 1996 and still has an online portal for those of us who still want to seek advice from the Oracle of Overhaul and DIY repairs. The phone number is essentially a customer service line now, but it’s still pretty handy when you need a hand with caulk, sealant, insulation foam, or wood filler.

Contains PC Bs Sign

An example of a sign warning about polychlorinated biphenyls.

Taking Care of PCB

Historically, caulk has been made from a wealth of different compounds. But for approximately 20 years (between the 1950s and 1970s), caulk contained dangerous, poisonous, and carcinogenic compounds called PCBs.

Polychlorinated biphenyls (PCBs) were common in construction between the 1950s and 70s (and were also used prior to that). But per the EPA, the stuff hasn’t been found in single-family homes from the period. It has, however, been found in older apartments, schools, and commercial buildings. And it’s pretty dangerous.

So, why is it such a big deal? PCBs are man-made chemicals—usually in the form of a yellow liquid or a black, waxy solid substance—that were used in a wide variety of construction materials for most of the 20th century, starting in 1929. They were in everything from paint, motor oil, and transformers to carbonless copy paper. The US banned them in 1979 due to their negative impact on everything from people to the environment. Some rivers—like Massachusetts’ Housatonic River—are still heavily contaminated by PCBs from that 50-year period. Fortunately, caulk no longer contains PCBs, but you still don’t want to ingest it or get it on your skin. If you do, The Poison Control Center recommends using it in a well-ventilated area, washing your hands after use, and flushing your eyes/washing your skin with cold water for 15 minutes.


The upper end of the range of buildings (many of them schools) in the United States where PCBs might still be present in caulk. The lower end of the range sits at 12,960, which is still a significant quantity in the grand scheme of things. According to the National Institute of Health, both field and lab studies have shown PCBs not only still exist in some buildings, but the PCBs contained within the caulk contribute to higher concentrations of PCBs in the building. Although the amounts in the air can vary, it’s still a significant problem that remains a subject of intense study for the time being.

Caulk and sealant are a remarkable part of construction history. Sometimes, a good caulking job can mean the difference between a secure building and a catastrophe, like that time a poor caulking job caused a molasses flood. And it’s pretty obvious that before the invention of the caulking gun, applying caulk took a lot more time. To say it was a game-changer is the understatement of the year. But in the end, the story of caulk is one of achievement, innovation, and tremendous success.

For some people, home improvement and maintenance are a burden; an unexpected and annoying variable that must be contended with at some point in our lives. For others, the spirit of DIY, the quiet mediation of painting or caulking, and the satisfaction of a job you complete yourself are wonderful, incomparable feelings that infuse one’s soul with joy.

Perhaps the reason I’m so fascinated by home repair, power tools, and This Old House these days is that it sort of ties me spiritually to my father, who passed away in April of this year. He was an avid reader of everything DIY, a regular This Old House (and other home improvement shows) viewer, and knew how to do everything from carpentry to electrical work. I learned a great deal from him, and it feels like I’m keeping his memory alive by using his tools and learning how to do these things.

Upon cleaning out his garage, I found a few decades’ worth of old issues of Popular Mechanics, Popular Science, Mechanix Illustrated, Smithsonian, National Geographic, and Popular Electronics (hey, Internet Archive, if you need any of these for the library, don’t hesitate to reach out). These magazines continue to be a source of inspiration and valuable information today, despite their age.

And among all of that stuff, I also found five caulking guns. I don’t know why he had so many, but I like to believe he would’ve found the history of the sealant as fascinating as we do.

This one’s for you, dad, wherever you are. Thanks for everything.


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David Buck

Your time was just wasted by David Buck

David Buck is a former radio guy/musician who researches and writes about all manner of strange and interesting music, legacy technology, Nintendo and data analysis.

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