Caulk is a common home improvement tool that most people have used at some point. Whether homeowners are smoothing defects in walls before painting or patching cracks that let drafts in, most people have probably used a spatula and this simple mixture to make basic home repairs. Most people do not think a lot about the history of such simple materials, but caulk actually has an interesting past. 

The first known mention of materials similar to caulk come from medieval times. Explorers such as Sir Walter Raleigh used natural pitch from Trinidad to repair and seal his ships. Natives similarly used pitch and even amber as a kind of caulk, a malleable sealant that could be placed in cracks and defects. The explorers who interacted with Native cultures quickly realized the benefits of this technology. However, pitch was more difficult to find in large quantities in Europe, leading to a search for a similarly malleable material that could be used as a sealant.

Sealing wax was invented in Europe in the 16th century and quickly began to be used in a way similar to Native American pitch and our own modern caulk. Sealing wax was used for sealing the top of cans used to store food and even to seal envelopes bearing important letters. As plumbing became more common, sealing wax was used more like caulk, to seal joints and other stressed areas in plumbing. People often made repairs using softened sealing wax. Lead also was used for a short time similarly to caulk, as it has a high melting temperature.

Unlike caulk, sealing wax is a hard solid at room temperature that becomes soft with minimal heat. It will soften again when exposed to heat, even the heat of a hot summer day. Caulk, on the other hand, is soft and malleable at room temperature but hardens with exposure. Thus, many people in the industrial world continued to search for a better sealing material, one that could be used at room temperature but also a solid at room temperature after application.

The answer came in the late 19th century, from a man named John Dicks. John was the son of a Robert Dicks, who produced sealing wax along with his partner Elmer Wiggin. John formulated and began producing caulk and other kinds of putty in large quantities. By the 1950s, this caulk could be bought in the small containers now used by homeowners. However, this caulk was very much like putty and hardened quickly while lacking malleability. In 1964, commercial companies discovered latex caulk, which offered the benefits of putty while remaining softer and more malleable. This kind of caulk also hardened without cracks and could be painted over. Acrylic latex caulk was later invented, further allowing easy working with a superior dried surface. It was not until the 1980s that silicone caulk, now a preferred type, was invented.

Caulk technology has steadily improved due to incredible demand for higher quality products. We now have specialty caulks for a variety of purposes, including latex painting, sealing of windows and doors, bathroom plumbing, roofing, and a variety of other applications. There are caulks that can be used effectively on metal surfaces as well as concrete and asphalt. There are even colored caulks that can be used to seal cracks in countertops without showing any marks. 

Many skilled craftsmen have learned techniques to use caulk combined with fillers to repair large cracks or holes. These techniques involve using a filler that is solid, such as wood or metal, and then caulking around and over these. While using modern caulk requires skill, most people can achieve basic proficiency quickly. Most of the learning curve involves using a steady hand and the right amount of pressure on caulking guns. Smoothing caulk similarly is an artistic skill, but one that can be mastered with a small amount of practice. 

From humble beginnings as plain organic pitch to pasty putties to modern silicone caulks, there is no doubt that this humble repair supply has changed over the centuries. Most people now have at least a passing familiarity with the usage of caulk, and it is a staple in the toolbox of most repairmen and construction specialists. There is likely not a single part of the modern home where caulk is not used. Because progress marches on, it is likely that there will soon be even more specialized caulks on the market. Although this is a humble and inexpensive ingredient, it is very important to modern life.