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Unlike gaskets that are manufactured in shapes and seal building joints under pressure, caulks and spray foams are manufactured as liquids or pastes that flow into place and adhere to the surrounding surfaces. These characteristics make them ideal for filling irregular joints and cavities that would be difficult to seal with gaskets, provided temperature and moisture conditions are suitable for bonding and curing. We offer professional-quality polyurethane and silicone caulks that are far superior to the consumer caulks sold in home centers, as well as a spray foam with environmental propellants.

HOW TO CAULK: Simply using a caulk that has a twenty to fifty year lifetime is no assurance that the caulk joint will last that long. If the caulk is not applied properly, the bond between the caulk and substrate can fail in just a few years and make the caulk worthless. A few basic rules for proper caulking follow:

• Design wide joints. A caulk that can accommodate 50% joint movement (typical of the best caulks) can fail with only 1/16” movement when sealing a 1/8” joint. The same caulk will withstand 1/4” movement when sealing a 1/2” joint.

• Apply caulks when the temperature is between 40°F and 100°F. The surface must be completely dry.

• Clean the surface: vacuum or wipe dust and dirt, then remove any oils or surface deposits with a suitable solvent.

• Use a backer rod to limit joint depth to half the joint width.

• Tool with a spoon or other rounded instrument to completely fill the joint and force the caulk against the sides.

poor caulk joint

Example of a poorly designed caulk joint. Excessive
caulk thickness makes the caulk difficult to stretch, leading
to failure of the bond between the caulk and substrate.


good caulk joint

Example of a well-designed caulk joint. Backer rod limits the
caulk thickness to half the joint width so that the caulk stretches
easily. Stress on the caulk-to-substrate bonds is minimal.


caulk tube

polyurethane and
silicone caulks

POLYURETHANE CAULK: Polyurethanes are probably the best general-purpose construction caulks available today – better than silicones for most common building applications. We offer a superior quality polyurethane that adheres to most common construction materials without primers, offers a long service life in severe climates, offers excellent cut and tear resistance, has exceptional elasticity, spans wide joints without sagging, tools and masks well, is non-toxic when cured, and is paintable. It is packaged in metalized cardboard tubes that offer twice the shelf life of plastic tubes used by cheaper brands. Polyurethane caulk becomes tack-free within eight hours and cures fully in about a week. It can be painted, but the paint will not stretch like the caulk and may crack or peel.

SILICONE CAULK: Although silicones are the most durable of all caulks, the bonding characteristics of most silicones are not as good as polyurethane. We recommend using silicone caulk for adhering our caulk-in silicone weatherstrip, for capping the exterior edges of our EPDM glazing gaskets, and for sealing joints between non-porous surfaces such as metal and glass. We offer a superior quality neutral-cure silicone that does not emit the noxious and corrosive acetic acid (vinegar) fumes typical of consumer-grade silicones, is stiff enough to span wide joints without sagging, and tools and masks well. Like all pure silicones, it should not be painted. Note that we do not offer clear silicone caulk or recommend their use: clear silicones are UV transparent and will permit sunlight to pass through the caulk and quickly deteriorate the bond between the caulk and substrate.

BACKER ROD: For optimal performance, a caulked joint should be shaped like an hourglass with the center thickness approximately half the joint width. The narrow center stretches easily with joint movement, and the wide sides offer maximal contact area with the substrate. This shape can be achieved by tooling the surface and by using a round “backer rod” to limit the depth of caulk penetration in a joint. We offer an advanced hybrid backer rod that compresses easily, works with any caulk, and doesn’t release gases that can ruin caulk joints. Stock diameters are 3/8” (joints 0 to 1/4”), 5/8” (joints 1/4” to 1/2”), 7/8” (joints 1/2” to 3/4”), and 1-1/8” (joints 3/4” to 1”).

caulk gun with caulk

professional caulk gun
with caulk cartridge

PROFESSIONAL CAULK GUNS: This is by far the best caulk gun we have ever used, a professional-quality tool that is much better made than similar-looking Far-East imports sold in home centers. It holds a standard 11 oz. cartridge and features comfortable, extra-long, cast-aluminum handles that make dispensing stiff-bodied caulks, adhesives, and sealants almost effortless. The frame is made of wide, thick steel ribs welded to a sturdy front plate and is designed so that the entire “cradle” can be rotated while caulking, eliminating the need to stop at corners. The drive shaft is made of hardened-steel and is smoothly driven with a jam-proof clutch mechanism. Quick-release levers stop the flow of caulk immediately at the end of a run. The gun can be completely disassembled for cleaning and all parts are replaceable.

foam gun with foamfoam

spray foam gun
with can of foam

SPRAY FOAM: Our single-component polyurethane spray foam does not contain CFC’s, HCFC’s, or formaldehydes, so it does not contribute to ozone depletion, global warming, or indoor air pollution. It bonds to most common building materials including concrete, masonry, stone, wood, fiberboards, metals, plaster, and foam insulation boards. Typical applications include filling pipe and wire penetrations, sealing around air-barrier blocking at rim joists, bonding foam panels to masonry or wood, sealing joints in structural insulated panels, and building rock walls in gardens and ponds . Considered a minimal-expansion foam, it can also be used to seal and insulate the shim space between window and door frames with less risk of bowing the frames than many other spray foams. (However, see BUILDING GASKETS for an alternative sealing method with zero bowing potential). We stock black foam that offers enhanced ultraviolet resistance outdoors, but it can be easily painted after a 24-hour cure.

We supply spray foam in twenty-four ounce recyclable aluminum cans designed to fit all standard foam applicator guns, and we offer two guns: an inexpensive plastic gun as well as a more durable all-metal professional-quality gun. “Gun foam” cans are much more economical than the unregulated single-use foam cans sold in home centers because the guns permit precise foam application and make it possible to store partially used cans for many weeks. One can of foam yields more than 2500 cubic inches (11 gallons) of expanded foam, the equivalent of several thousand feet of caulk.

For best results, the application temperature should be between 40°F and 95°F. Surfaces should be clean and free from dust and oils. Non-porous surfaces such as metal or wood should be dry, but porous surfaces such as masonry should be moistened with a fine mist of water. Fill shallow joints and cavities about three-quarters to allow room for expansion. When filling deep cavities, apply several layers of foam at intervals of one to two hours. Always leave a can of foam in the gun, and flush the gun with Spray Foam Cleaner before installing a new can of foam (order one cleaner for every six cans of foam).



Professional Caulk Gun - $19.00
Polyurethane Caulk, bronze, 11 oz - $5.20
Polyurethane Caulk, limestone gray, 11 oz - $5.20
Polyurethane Caulk, white, 11 oz - $5.20
Silicone Caulk, black, 11 oz - $8.20
Silicone Caulk, bronze, 11 oz - $8.20
Silicone Caulk, white, 11 oz - $8.20
Backer Rod, 3/8”, cut to length - $0.16/ft
Backer Rod, 3/8”, 1800’ roll - $116.00
Backer Rod, 5/8”, cut to length - $0.24/ft
Backer Rod, 5/8", 1550’ roll - $120.00
Backer Rod, 7/8”, cut to length - $0.40/ft
Backer Rod, 7/8”, 850’ roll- $128.00
Backer Rod, 1-1/8”, cut to length - $0.56/ft
Backer Rod, 1-1/8”, 500’ roll - $112.00
Black Spray Foam, 24oz - $16.00
Spray Foam Cleaner - $12.00
Spray Foam Gun, economy - $36.00
Spray Foam Gun, professional - $56.00

Note: Sealants are not returnable.


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