Caulk (also known as caulking and calking)
The oldest form of caulk consisted of fibrous materials driven into the wedge-shaped seams between boards on wooden boats or ships. Cast iron Sanitary sewer pipes were formerly caulked in a similar way. Riveted seams in and were formerly sealed by hammering the metal.
Modern caulking compounds are flexible sealing compounds used to close up gaps in and other structures against water, air, dust, , or as a component in . In the industry, caulking is the sealing of joints in segmental precast concrete tunnels, commonly by using concrete.
Historical uses
Traditional caulking (also spelled calking) on wooden vessels uses
of
cotton and
oakum (
hemp) 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.
In riveted steel or iron
Shipbuilding, 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.
Caulking of iron and steel was also used by in the era of riveted Steam boiler to make the joints watertight and steamtight.
Modern use in construction
Application
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
.
For smaller applications, caulk may be distributed in squeeze 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.
Closed-cell foam does not absorb water and is impermeable. Closed-cell rods are less compressible and should not be compressed more than 25%.
Out-gassing is the reason that open-cell backer rod was developed.
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.
Preventing infestation
Sealing cracks and crevices prevents ingress by rodents.
Types
Acrylic latex
The most common type of caulk is acrylic latex, for general-purpose use.
Not only is acrylic latex inexpensive, but it is also the easiest type to apply smoothly and later paint if needed.
Acrylic tile sealant
Acrylic tile sealant usually comes in small tubes and is commonly used for wet applications.
Polyurethane
Polyurethane caulk is very durable
construction sealant. It has good adhesion towards concrete, wood, metals (steel, aluminium), plastic, masonry etc.
It's commonly used for sealing ventilation systems.
Silicone
Silicone caulk or sealant is water-, mold-, and mildew-resistant.
Technically, when a joint material is silicone-based, it is considered a
sealant rather than caulk.
See also
External links
