Caulk or (less frequently) caulking[1] is a material used to seal joints or seams against leakage in various structures and piping.

The oldest form of caulk consisted of fibrous materials driven into the wedge-shaped seams between boards on wooden boats or ships. Cast iron sewerage pipe were formerly caulked in a similar way. Riveted seams in ships and boilers were formerly sealed by hammering the metal.[2]

Modern caulking compounds are flexible sealing compounds used to close up gaps in buildings and other structures against water, air, dust, insects, or as a component in firestopping. In the tunnelling industry, caulking is the sealing of joints in segmental precast concrete tunnels, commonly by using concrete.

Caulking, USAF
Man applying caulk to baseboard

Historical uses

Wooden shipbuilding

Caulked hull timbers, Spry, Blists Hill
Dried-out caulking on the Severn trow Spry, now displayed on shore
Caulking tools
The tools of traditional wooden ship caulking: caulking mallet, caulker's seat, caulking irons, cotton and oakum
MaryRose-caulking tools2
A caulking mallet, tar pot and a piece of petrified tar found on board the 16th century carrack Mary Rose

Traditional caulking (also spelled calking) on wooden vessels uses fibers of cotton and oakum (hemp fiber soaked in pine tar). These fibers are driven into the wedge-shaped seam between planks, with a caulking mallet and a broad chisel-like tool called a caulking iron. The caulking is then covered over with a putty, in the case of hull seams, or else in deck seams with melted pine pitch, in a process referred to as paying, or "calefaction". Those who carried out this work were known as caulkers.

Modern marine sealants are frequently used now in place of the pitch, or even to supplant the oakum and cotton itself.

Iron or steel shipbuilding

In riveted steel or iron ship construction, caulking was a process of rendering seams watertight by driving a thick, blunt chisel-like tool into the plating adjacent to the seam. This had the effect of displacing the metal into a close fit with the adjoining piece.[3] Originally done by hand much like wooden vessel caulking, pneumatic tools were later employed. With the advent of electric-arc welding for ship construction, steel ship caulking was rendered obsolete.


Caulking of iron and steel, of the same type described above for ship's hulls, was also used by boilermakers in the era of riveted boilers to make the joints watertight and steamtight.[4]

Modern use in construction

To caulk in the building trades is to close up joints and gaps in buildings. Caulking provides thermal insulation, controls water penetration and reduces noise transmission.

Caulking underneath bathroom sink
Silicone-based caulk on this upturned bathroom sink will spread smoothly, sealing the gap, when the sink is turned over and installed.

This is mostly done with ready-mixed construction chemicals sold as caulk such as silicone, polyurethane, polysulfide, sylil-terminated-polyether or polyurethane and acrylic sealant.


Silicone caulking extruded from a caulking gun

For bulk use, caulk is generally distributed in disposable cartridges, which are rigid cylindrical cardboard or plastic tubes with an applicator tip at one end, and a movable plunger at the far end. These are used in caulking guns, which typically have a trigger connected to a rod which pushes the plunger, and has a ratchet to prevent backlash. The push rod may also be actuated by a motor or by compressed air. Similar mechanisms are used for grease guns.

For smaller applications, caulk may be distributed in squeezable tubes.

Backer rod

Backer rod, also called backer material or back-up rod, is a flexible foam product used behind caulking to increase elasticity, reduce consumption, force the caulking into contact with the sides of the joint creating a better bond, determine the thickness of the caulking, and define the cross-section hour-glass shape of the caulk. The backer rod also acts as a bond breaker to keep the caulking from sticking to the bottom of the opening—called a three-sided bond—with the caulk only adhering to the sides of the opening in an hour-glass shape it can flex more easily and is less likely to tear. Backer rods can also be used to reduce consumption of the caulking by filling part of the joints.

Backer rod is often round and rope-like in shape but many special types and shaped such as square, rectangular and D-shapes are available. High temperature backer rods are available. It is available in different diameters and firmness, and in polyethylene and polyurethane materials. Backer rod also comes in open-cell and closed-cell types of foam.

Open-cell foam is porous so it will let gasses through which could otherwise cause blistering of the sealant. Also, open-cell backer rod allows air to get to the back side of the sealant which accelerates curing when used with air-cured sealants such as silicone. Open-cell rod is more compressible than closed-cell foam and should be 25% larger diameter than the joint.

Closed-cell foam does not absorb water and is impermeable. Closed-cell rods are less compressible and should not be compressed more than 25%. Closed-cell rod will also lose firmness and out-gas if damaged during installation or overcompressed or at sharp bends. The gasses cannot pass through this backer rod and can deform, weaken, and even cause holes (leaks) in the sealant as it escapes. Out-gassing is the reason open-cell backer rod was developed.[5]

Energy efficiency

According to the Consumer Federation of America, sealing unwanted leaks around homes is an excellent way to cut home energy costs and decrease the household carbon footprint.

Also, sealing cracks and crevices around homes puts less strain on home appliances and can save time, money and hassle by preventing major repairs. Additionally, increasing the lifetime of homes and appliances also puts less waste and pollution into landfills.

Preventing infestation

Sealing cracks and crevices prevents ingress by rodents.[6]


  1. ^ Merriam-Webster Dictionary s.v.
  2. ^ Walter S. Hutton, Steam-boiler Construction, 1898, p. 230
  3. ^ "Navigation and Vessel Inspection Circulars (NVIC): USCG" (PDF).
  4. ^ Colvin, Fred H. (1906). The railroad pocket-book: a quick reference cyclopedia of railroad information. New York, Derry-Collard; London, Locomotive Publishing Company (US-UK co-edition). p. C‑9.
  5. ^ Gibb, J. F. (March 1980). "Hidden, but Essential: A Technical Review of Backer Rods" (PDF). The Construction Specifier. pp. 40–45.
  6. ^ "Seal Up!". Centers for Disease Control and Prevention. 2010-07-29. Retrieved 2015-11-17.

External links

'Abd Allah II ibn 'Ali 'Abd ash-Shakur

Abd Allah II ibn 'Ali 'Abd ash-Shakur, also known as Amir Hajji 'Abdu'llahi II ibn 'Ali 'Abdu's Shakur, (18??-1930) was the last Emir of Harar from 1884 (or 1885, various sources carry various dates) to January 26, 1887, when the state was terminated, following the defeat of the Harari troops at the Battle of Chelenqo (January 6).

According to R.A. Caulk, Emir 'Abd Allah was the son of Muhammad ibn `Ali `Abd ash-Shakur by Kadija, the daughter of Emir `Abd al-Karim ibn Muhammad. To secure his hold on the emirate of Harar, his father had married 'Abd Allah to the daughter of Ahmad III ibn Abu Bakr, his predecessor. When the Egyptians evacuated Harar, 'Abd Allah became the logical choice to rule Harar. He was given "a few hundred soldiers trained by one of the British officers, 300 to 400 rifles, some cannon, and munitions, a force hardly sufficient to garrison Harar and Jaldessa, let alone police the traderoutes and ensure the security of the state."Emir 'Abd Allah grew anxious about the growing Ethiopian threat to his domain, and accused the resident Europeans of co-operating with Negus Menelik II. His situation deteriorated by July 1885, according to historian Harold Marcus: "the population grew uncontrollable, European traders became virtual prisoners in their homes and shops, and the adjacent Galla raided the town." In response, the Emir introduced a new currency which impoverished the local population. The neighboring Oromo and Somali deserted Harar's markets and the town's economy collapsed.

The Ughaz or Sultan of the Gadabuursi, Ughaz Nur II, had established strong relations with the Emir of Harar, Abdallah II ibn Ali. In 1887, when Harar was occupied by Menelik II of Ethiopia, Ughaz Nur sent Gadabursi askaris to support Abdallah II ibn Ali. Emir 'Abd Allah responded to the first Ethiopian military probe with a night attack on their camp at Hirna that included fireworks; the Ethiopians panicked at the pyrotechnics and fled toward the Asabot and Awash Rivers. When the Negus Menelik personally led a second attack a few months later, the Emir misjudged the quality of these troops and attempted to repeat his earlier success of a second night attack. "Had he allowed the enemy to attack the walled city, where his few Krupp cannon might have been effective, the Shoans might have suffered a defeat with serious political consequences," Marcus notes. However, the battle at Chelenqo destroyed the Emir's army in fifteen minutes and, with his wives and children, the Emir fled into the empty country east of Harar. He left his uncle Ali Abu Barka to submit to Menelik and ask clemency for Harar.The former Emir 'Abd Allah later returned to the town to live as a Sufi or religious scholar. He died there in 1930.

Baboon (band)

Baboon is an American rock band originally from Denton, Texas.

The band formed in 1991. Their latest studio album, titled Baboon, was released on October 10, 2006.

Baboon appeared on an episode of Walker, Texas Ranger titled "Hall of Fame" in 1996. The band and their music were a key point in the episode's plot.

In its early years, Baboon, Brutal Juice, and Caulk were known collectively in the Denton area as the "Fraternity of Noise." Baboon toured extensively, including a stint on the Skoal-sponsored R.O.A.R. Tour in 1997, along with acts such as Iggy Pop, The Reverend Horton Heat, The Bloodhound Gang, and Sponge. They also toured with Toadies, Brutal Juice, and Unwound.

Vocalist Andrew Huffstetler and guitarist Mike Rudnicki formed The Boom Boom Box in 2008 and released a self-titled EP later than year, and a full-length album, titled Until Your Eyes Get Used To The Darkness, through Kirtland Records in 2012.

Caulk boots

Caulk boots or calk boots (also called cork boots, timber boots, logger boots, logging boots, or corks) are a form of rugged footwear, most often associated with the timber trade but also suitable for use in hiking and in other heavy industry such as manufacturing and construction, due to their safety features.Timber boots are typically made of leather or suede uppers extending over the ankle, with a thick rubber sole to provide protection and grip, and bearing deep treads or spikes. The ankle is typically cuffed with padded leather.


A caulkin (or caulk; US spelling "calkin" or "calk") from the Latin calx (the heel) is a blunt projection on a horseshoe or oxshoe that is often forged, welded or brazed onto the shoe. The term may also refer to traction devices screwed into the bottom of a horseshoe, also commonly called shoe studs or screw-in calks. These are usually a blunt spiked cleat, usually placed at the sides of the shoe.

Caulking (video games)

Caulking is a process used in video game level creation or editing (or mapping) for the generation of a level, or map, that when compiled is less demanding for the computer's graphics card to render in-game than it would be otherwise. A surface that is marked with caulk is not drawn in-game, and is commonly shown as bright pink within the map editor.

Inevitably, certain sides of some objects (e.g. walls) in a game scene will never be visible to the player during normal play. The person making the map can apply the caulk texture, instead of a normal texture, to these surfaces when building the map. The surfaces become invisible in-game and if compiled into a Binary Space Partitioning-File (or BSP-Level) they will also not be added to the list of Leaves (or convex polygons). The resulting reduction of polygons and textures used in the video game level reduces the required video card resources, possibly making the map smoother to play. In the case that a surface which was not meant to be visible inadvertently becomes visible, possibly due to a mapping error, some game engines support drawing caulked surfaces using flat shading.

The conscientious mapper will caulk every side of every building block (or brush) in a map that will never be seen by the player. This is easily done by caulking all sides of a new brush by default, and then by only applying normal textures to those sides that will be seen in the game.

Delaware Constitution of 1831

The Delaware Constitution of 1831 was the third governing document for Delaware state government and was in effect from its adoption on December 2, 1831 until replaced on June 4, 1897 by the present state Constitution.

Members of the Delaware Constitutional Convention of 1831. The Convention convened in 1831 and adjourned December 2, 1831.

Charles Polk, Jr. President

Thomas Adams

John Caulk

John M. Clayton

Peter L. Cooper

Thomas Deakyne

Edward Dingle

William Dunning

John Elliott

James Fisher

Willard Hall

Thomas W. Handy

John Harlan

Charles H. Haughey

Hughitt Layton

James C. Lynch

James B. Macomb

Joseph Maull

Elias Naudain

Wiliam Nicholls

Samuel Ratcliff

John Raymond

George Read, Jr.

Henry F. Rodney

James Rodgers

William Seal

Pressley Spruance, Jr.

William D. Waples

El Calafate

El Calafate is a city in Patagonia, Argentina. It is situated on the southern border of Lake Argentino, in the southwest part of the Santa Cruz Province, about 320 km Northwest of Río Gallegos. The name of the city is derived from a little bush with yellow flowers and dark blue berries that is very common in Patagonia: the calafate (Berberis buxifolia); the word comes from the word "calafate", which is Spanish for "caulk".

El Calafate is an important tourist destination as the hub to visit different parts of the Los Glaciares National Park, including the Perito Moreno Glacier and the Cerro Chaltén and Cerro Torre.

G. Wallace Caulk Jr.

G. Wallace "Wally" Caulk, Jr. (born February 7, 1941) is an American politician. He was a Republican member of the Delaware House of Representatives, representing District 33 from 1985 until his retirement in 2006.


Hyperseal is the brand name for a series of specialized paints developed by noted inventor Col. Ronald Savin. The paints are divided into three categories: glass-infused paints, Hyperglass, zinc-infused paints, Hyperzinc, and rubber infused paints, Hyperflex. The paints were developed to significantly cool surfaces in the desert, seal out water and galvanize rust.

Part of a wave of environmentally friendly, “green products,” the paints are intended to significantly decrease energy expenditure, prevent toxic run-off from asphalt driveways, and ensure that water born vessels, marinas and bridges need only be repainted every 20 years to prevent rust; instead of once a year.

Hyperglass is the first paint formulated with hollow glass “microspheres” suspended in a specialized white Teflon paint. The paint has the remarkable ability to keep a surface in direct sunlight only 10 – 12 °F above ambient air temperature. The paint is used to coat roofs, patios and boat decks. Before this, a typical asphalt roof would be 50 – 75 °F higher than the ambient air. In Southern California, homes with Hyperglass painted roofs, have seen a reduction of 50% of their air conditioning bills, thus significantly reducing their carbon footprint. Hyperseal has also developed a multipurpose caulk, called Hyperflex Caulk.


A Klabautermann is a water kobold that assists sailors and fishermen on the Baltic and North Sea in their duties. It is a merry and diligent creature, with an expert understanding of most watercraft, and an irrepressible musical talent. It is believed to rescue sailors washed overboard. The name comes from the Low German verb klabastern meaning "rumble" or "make a noise". An etymology deriving the name from the verb kalfatern ("to caulk") has also been suggested.His image is of a small sailor in yellow with a tobacco pipe and woolen sailor's cap, often carrying a caulking hammer. This likeness is carved and attached to the mast as a symbol of good luck.

Despite the positive attributes, there is one omen associated with his presence: no member of a ship blessed by his presence shall ever set eyes on him. He only ever becomes visible to the crew of a doomed ship.

More recently, the Klabautermann is sometimes described as having more sinister attributes, and blamed for things that go wrong on the ship. This incarnation of the Klabautermann is more demon- or goblin-like, prone to play pranks and, eventually, doom the ship and her crew. This deterioration of image probably stems from sailors, upon returning home, telling stories of their adventures at sea. Since life at sea can be rather dull, all creatures - real, mythical, and in between - eventually became the centre of rather ghastly stories.

Lead wool

Lead wool consists of thin strands of lead metal that can be used to cold-caulk cast iron and steel pipes.

It was manufactured by the New York Lead Wool Company in the United States and by The Lead Wool Company, Limited in Snodland, Kent, England.The Lead Wool Company (the British company) was incorporated on 9 October 1919 (although some references indicate that it was active before that date) and was still active in 1983. The British company also developed a device to test pipe joints internally.The company's factory had been demolished by 1994, according to a report on archaeological excavations near the factory's site.Lead wool is manufactured in the UK by Calder Industrial Materials Limited.

Mount Grier

Mount Grier (86°41′S 148°57′W) is a prominent mountain, 3,035 metres (9,960 ft) high, standing at the east side of the Scott Glacier where it forms the westernmost summit of the La Gorce Mountains, in the Queen Maud Mountains of Antarctica. It was discovered in December 1934 by the Byrd Antarctic Expedition geological party under Quin Blackburn, and named by Richard E. Byrd for Dr. G. Layton Grier, head of the L.D. Caulk Company of Milford, DE, who contributed dental supplies to the Byrd expeditions of 1928–30 and 1933–35.

New Girl (season 2)

The second season of the American television sitcom New Girl premiered on Fox on September 25, 2012, and concluded on May 14, 2013, consisting of 25 episodes. Developed by Elizabeth Meriwether under the working title Chicks & Dicks, the series revolves around offbeat teacher Jess (Zooey Deschanel) after her moving into a Los Angeles loft with three men, Nick (Jake Johnson), Schmidt (Max Greenfield), and Winston (Lamorne Morris); Jess's best friend Cece (Hannah Simone) also appears regularly. The show combines comedy and drama elements as the characters, who are in their early thirties, deal with maturing relationships and career choices.

Rope caulk

Rope caulk or caulking cord is a type of pliable putty or caulking formed into a rope-like shape. It is typically off-white in color, relatively odorless, and stays pliable for an extended period of time.

Rope caulk can be used as caulking or weatherstripping around conventional windows installed in conventional wooden or metal frames (see glazing). It is also used as a form for epoxy work, since epoxy does not adhere to this material.

Rope caulk has also been applied to the metallic structure supporting the magnet for a dynamic speaker to cut unwanted resonance of the metal structure, leading to improved speaker performance. It has also been used as a sonic damping material in sensitive phonograph components.

Santa Monica–Malibu Unified School District

Santa Monica–Malibu Unified School District is a school district located in Santa Monica, California, United States. The district serves the cities of Santa Monica and Malibu. It has ten elementary schools, two middle schools, three high schools, an adult high school, and an alternative school.

In 2009 Malibu High School underwent a Polychlorinated biphenyls clean up. In 2011 the construction project on the Malibu Middle and High Schools and Juan Cabrillo Elementary School found soils contaminated with PCB and organochlorine pesticides. The levels present represented “an unacceptable health risk.” In 2014 the continued contamination was linked to caulk. In March 2015 parents and teachers filed a lawsuit to remove all contaminated caulk from the premises.


Silicones, also known as polysiloxanes, are polymers that include any synthetic compound made up of repeating units of siloxane, which is a chain of alternating silicon atoms and oxygen atoms, combined with carbon, hydrogen, and sometimes other elements. They are typically heat-resistant and either liquid or rubber-like, and are used in sealants, adhesives, lubricants, medicine, cooking utensils, and thermal and electrical insulation. Some common forms include silicone oil, silicone grease, silicone rubber, silicone resin, and silicone caulk.

Spruce gum

Spruce gum is a chewing material made from the resin of spruce trees. In North America, spruce resin was chewed by Native Americans, and was later introduced to the early American pioneers and was sold commercially by the 19th century, by John B. Curtis amongst others. It has also been used as an adhesive. Indigenous women in North America used spruce gum to caulk seams of birch-bark canoes.Spruce gum has been used medicinally, primarily to heal deep cuts and sores in the Dene culture. In the 1870s, Sisters of Providence located in Montreal, Canada, developed a spruce gum syrup for treating coughs and bronchitis.In the 20th century, commercial spruce tree processing turned to paper manufacturing to meet demand from the newspaper industry, thereby reducing the availability of spruce for other purposes, including Spruce Gum. Today, it is available in small batches made at home rather than commercially. It is often flavored with mint or fruit. It is also found in nature and is far less expensive than purchasing a small batch.

Tube (container)

A tube, squeeze tube, or collapsible tube is a collapsible package which can be used for viscous liquids such as toothpaste, artist's paint, adhesive, caulk, ointments, and so on. Basically, a tube is a cylindrical, hollow piece with a round or oval profile, made of plastic, paperboard, aluminum, or other metal. In general, on one end of the tube body there is a round orifice, which can be closed by different caps and closures. The orifice can be shaped in many different ways: plastic nozzles in various styles and lengths are most typical. The other end is sealed either by welding or by folding.

Typical tube sizes range from 3ml to 300ml. Most tubes are designed to be dispensed with hand pressure, but some are used with a tube key at the base to help roll them up.

`Abd al-Karim ibn Muhammad

`Abd al-Karim ibn Abu Bakr was the Emir of Harar, Ethiopia (1825 - 1834). According to the British explorer Richard F. Burton, he was the brother of `Abd ar-Rahman ibn Muhammad.On the death of his brother, Emir Ahmad II ibn Muhammad, `Abd al-Karim and his other brother `Abd ar-Rahman quarreled over who would succeed, and `Abd ar-Rahman gained the throne first with the help of the Babille Oromo who dwelled to the east of Harar. However, while returning from an unsuccessful campaign to extract tribute from the Ala Oromo in 1825, he was betrayed to these people and `Abd al-Karim made himself Emir. Abd al-Rahman appealed for help from his Babille allies, who helped him resist his deposition. In the end, `Abd ar-Rahman was deposed and forty villages are listed as having been destroyed by the Oromo to the north, west and south of harar, as well as in Babille country during this civil war.According to Richard F. Burton, `Abd al-Karim had recruited 60 or 70 Arab matchlockmen, under one Haydar Assal the Auliki, to wage war against the neighboring Oromo who were threatening Harar. However, the battle went against the Harari and the Arab mercenaries, the latter suffering twenty casualties before retreating within the walls of the city. The Oromo managed to enter Harar, captured both `Abd al-Karim and `Abd ar-Rahman, and aided by the inhabitants of the city attempted to slaughter the remaining Arab mercenaries. "These, however," writes Burton, "defended themselves gallantly, and would have crowned the son of Abd al-Rahman, had he not in fear declined the dignity; they then drew their pay, and marched with all the honours of war to Zeila." R.A. Caulk explains that this was a garbled version of the fraternal battle for the throne.According to Harari tradition, the reign of `Abd al-Karim was a golden age. "Abd al-Karim is popularly depicted as a

wise and just ruler and a militant proselytizer of the Oromo," writes Caulk. "He made himself so respected outside the walls, it is claimed, that the Qottu regularly paid their taxes and even the leaders of the independent Oromo gave ready redress for all injuries done to the townspeople."


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