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 Mobile ViewEXTERIORS of buildings ADHESIVES, EXTERIOR CONSTRUCTION AGE of a BUILDING - how to determine ALGAE, FUNGUS, LICHENS, MOSS ANIMAL ENTRY POINTS in buildings ANIMAL ODORS IN buildings ARCHITECTURE & BUILDING COMPONENT ID ASBESTOS ROOFING / SIDING DUST ATTIC CONDENSATION CAUSE & CURE BARK SIDE DOWN on DECKS, TRIM, STEPS BASEMENT WATERPROOFING BEST CONSTRUCTION PRACTICES GUIDE BRICK FOUNDATIONS & WALLS BRICK STRUCTURAL WALL Loose Bulged BRICK VENEER WALL Loose, Bulged BRICK WALL DRAINAGE WEEP HOLES BOOKSTORE - EXTERIORS BUILDING SAFETY HAZARDS GUIDE BUILDING SETTLEMENT CAULK GUN TYPES, CHOICES CAULKS & SEALANTS, EXTERIOR CHIMNEY INSPECTION DIAGNOSIS REPAIR CATCH BASINS DECK & PORCH CONSTRUCTION DECK FINISHES COATINGS PRESERVATIVES DEFINITIONS of ENGINEERED WOOD OSB LVL etc DRYWELLS, FRENCH DRAINS for FLAT SITES EARTHQUAKE DAMAGED FOUNDATIONS ENERGY SAVINGS in buildings EXTERIOR WALL SIDING TRIM & FINISHES FLASHING MEMBRANES PEEL & STICK FLASHING for METAL ROOFS FLASHING ROOF WALL DETAILS FLASHING ROOF-WALL SNAFU FLASHING SIDING DETAILS FLASHING WALL DETAILS FLASHING WOOD ROOF DETAILS FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP FROST HEAVES, FOUNDATION, SLAB FOOTING & FOUNDATION DRAINS FOUNDATION WATERPROOFING FRENCH DRAINS GALVANIC SCALE & METAL CORROSION GLUES ADHESIVES, EXTERIOR CONSTRUCTION GRADING & SITE WORK, EXTERIOR GUTTERS & DOWNSPOUTS HEAT TAPES & CABLES on Roofs for Ice Dams HOUSE PARTS, DEFINITIONS HOUSEWRAP INSTALLATION DETAILS HUMIDITY LEVEL TARGET ICE DAM PREVENTION INDOOR AIR QUALITY & HOUSE TIGHTNESS KIT HOMES, Aladdin, Sears, Wards, Others LEAD POISONING HAZARDS GUIDE LEED GREEN BUILDING CERTIFICATION LOG HOME GUIDE LIGHTNING PROTECTION METAL LATH, PLASTER & STUCCO MOISTURE CONTROL in BUILDINGS MOISTURE CALCULATIONS MOISTURE PROBLEMS: CAUSE & CURE MOLD DETECTION & INSPECTION GUIDE MVOCs & MOLDY MUSTY ODORS ODORS & SMELLS DIAGNOSIS & CURE OIL TANKS PAINT & STAIN GUIDE, EXTERIOR PAINT & STAIN LIFE CHART PAINT & STAIN SELECTION & PROCEDURES PAINT ANALYSIS, DIAGNOSTIC USES PAINT FALURE, DIAGNOSIS, CURE, PREVENTION PAINT FAILURE DICTIONARY PAINT LAB SAMPLE PREPARATION PAINT SURFACE PREPARATION PAINTING MISTAKES PORCHES & Sunrooms PORCH CONSTRUCTION & SCREENING RAILINGS, DECK & PORCH RAILINGS, STAIRWAY RETAINING WALL DESIGNS, TYPES, DAMAGE RETAINING WALL GUARD RAILINGS ROOF CLEANING RECOMMENDATIONS ROOF VENTILATION SPECIFICATIONS ROT, FUNGUS, TERMITES ROT, TIMBER FRAME SEARS KIT HOUSES SEPTIC & CESSPOOL SAFETY SEPTIC SYSTEM INSPECT DIAGNOSE REPAIR SHEATHING, Gypsum board SHEATHING Homasote & Other Board SHEATHING, OSB SHEATHING, Plywood SHEATHING, FOIL FACED - VENTS SIDING, Sheathing Identification - Photo Guide SIDING, ALUMINUM SIDING, ASBESTOS FIBER CEMENT SIDING ASPHALT ROOF SHINGLES on WALLS SIDING ASPHALT SHINGLE or SHEET SIDING DAMAGE by SPLASHBACK SIDING EIFS & STUCCO SIDING, FIBER CEMENT SIDING HARDBOARD SIDING STEEL SIDING VINYL SIDING, WOOD PRODUCT CHOICES SIDING, WOOD INSTALLATION SIDING WOOD, FAILURES OVER FOAM BOARD SIDING WOOD, FLASHING DETAILS SIDING WOOD SHINGLE INSTALLATION SINKHOLES, WARNING SIGNS SOLAR ENERGY SYSTEMS SOUND CONTROL in buildings STAINS on buildings - QUICK GUIDE STAIN DIAGNOSIS on BUILDING EXTERIORS STAIN DIAGNOSIS on BUILDING INTERIORS STAINS on INDOOR SURFACES: PHOTO GUIDE STAINS & Thermal Tracking STAIN DIAGNOSIS on ROOFS STAIN DIAGNOSIS on STONE STAIRS, RAILINGS, LANDINGS, RAMPS STONE CLEANING METHODS STONE VENEER WALLS STUCCO WAll FAILURES DUE TO WEATHER STUCCO WALL METHODS & INSTALLATION STUCCO OVER FOAM INSULATION STUCCO PAINT FAILURES SURFACE GRADING, SITE DRAINAGE TERMITES, ROT THERMAL EXPANSION of MATERIALS THERMAL MASS in buildings TREES & SHRUBS, TRIM OFF BUILDING TRIM, EXTERIOR CHOICES, INSTALLATION VAPOR BARRIERS & CONDENSATION in BUILDINGS VENTILATION in buildings VINYL Siding or PLASTIC Window ODORS in buildings VINYL CHLORIDE HEALTH INFO WATER BARRIERS, EXTERIOR BUILDING WATER ENTRY in buildings WIND ENERGY SYSTEMS WIND TURBINES & LIGHTNING WINDOWS & DOORS WINTERIZE A BUILDING More Information |
This article discusses the selection and proper application of exterior caulks and sealants on buildings. This article series discusses best practices construction details for building exteriors, including water and air barriers, building flashing products & installation, wood siding material choices & installation, vinyl siding, stucco exteriors, building trim, exterior caulks and sealants, exterior building adhesives, and choices and application of exterior finishes on buildings: paints, stains. This article series includes excerpts or adaptations from Best Practices Guide to Residential Construction, by Steven Bliss, courtesy of Wiley & Sons. Our page top photo of an open caulk joint over a window demonstrates that even with the best-performing sealants on the market, workmanship remains critical if the sealant (or caulk) is going to actually work to keep water out of the structure. See CAULK GUN TYPES, CHOICES, and also see GLUES ADHESIVES, EXTERIOR CONSTRUCTION. Some caulks and sealants also act as glues or adhesives. © Copyright 2012 InspectAPedia.com, Daniel Friedman, Steve Bliss, Wiley & Sons, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website. Best Practices Guide to Caulks & Sealants for Building Exterior Use
While no residential exteriors should rely solely on caulks and sealants to keep water out, many details require caulk either to mask an expansion joint between materials or as the first line of defense against leakage. When choosing a caulk or sealant (another name for a high-performance caulk), look for a product that will bond well to the substrate materials and be sufficiently flexible to tolerate the anticipated movement (Table 1-13). Just as important is how the caulk bead is applied. The best quality caulk will fail if applied 1 inch thick and bonded on three sides of the joint. Our photo (above left) of caulk over a building window shows another view of the poor workmanship in our page top photo, and explains that over this window there is a risk of building leaks. Table 1-13: Caulk & Sealant Performance below summarizes the properties of different types of caulks and sealants. [Click any table or image to see an enlarged, detailed version.]
Caulk Joint Design to Avoid Failures: Ideal Joint Shape
This shape allows a caulk bead to stretch without either failing in “adhesion” to the substrate materials or failing in “cohesion” by tearing itself. A good rule-of-thumb is that a caulk joint should be four times the width of the anticipated movement, limiting the sealant’s stretching to 25%. For most residential building details, this requires at least a 1/4-inch-wide joint. In general, the sealant should be no more than 1/2-inch deep. For deep joints, it is best to pack the joint with a backer rod, a flexible foam material that controls the depth of sealant and shapes it into the hourglass profile. Backer rod is made of either open-cell or closed-cell foam and comes in diameters from 1/4-inch to as much as 2 inches. In wet locations, such as concrete control joints, use closed-cell foam, since it will not absorb water. Use a backer rod a little bigger than the joint being sealed. Bond Breakers - Use of Backer Rods in Wide Caulk Joints
For corner joints, use a small diameter backer rod or any other material that will not bond to the sealant. Plastic and foam tapes sold for weather stripping can work in corners (see Figure 1-38). [Click image for additional details]. Cleaning and Priming Requirements for Successful Caulk & Sealant UseSince dirt, debris, and loose paint act as bond breakers, sealing to a dirty or flaking joint will fail when the joint moves. Also, the joint should be dry unless using a sealant approved for damp surfaces, such as some polyurethanes and some of the newer synthetic-rubber “Kraton” type sealants. Do not use compressed air to clean the joints unless a line filter is also used, since the oil from the compressor may coat the joint, interfering with the bond. Although priming is not required for most sealants used in residential construction, some metals may need priming with acid-cure silicones. Consult the sealant manufacturer’s specifications. Caulk & Sealant Standards & SpecificationsFor critical joints where movement is anticipated, choose a caulk that complies with ASTM C920 and is rated for /25% movement. ASTM C920 indicates that the sealant is highly weather-resistant, durable, and shrinks no more than 10%. For stationary joints, a +/- 12.5% rating for joint movement is acceptable. Guide to Using Silicone Caulks & Sealants on Building Exteriors
Once cured, silicone caulks and sealants can also tolerate temperatures from well below 0°F to about 400°F, or higher for special high-temperature formulations. Unlike most sealants, silicone stays flexible when cold. Silicones are also very resistant to UV radiation and water, making them a good choice for exteriors as well as kitchens and baths. The main disadvantages of silicone are that it is messy to work with, difficult to tool [notice the irregular bead of silicone caulk in our photo above], and does not hold paint well. Cleanup when wet requires acetone or special-order silicone solvent, and the residue is hard to remove when it is time to reapply. Because of the residue, once you’ve sealed a joint with silicone, it is best to reseal with silicone as well. Silicone does not bond well to unpainted wood and can stain or degrade porous stone and masonry materials. Silicones come in two types: acid-cure (acetoxy) and neutral-cure (sometimes called “noncorrosive” silicone). The acid-cure type has a distinctive vinegar like odor. Both types will stick well to glass, ceramics, and other nonporous surfaces. Acid-cure silicone, however, requires primer with most metals to bond well and to avoid corrosion. Neutral-cure silicones are compatible with most metals and metal finishes and bond somewhat better to wood. Guide to Using Polyurethane Caulks & Sealants on Building Exteriors: Urethane CaulksPolyurethane is a versatile, water-resistant, high performance sealant and has become the first choice of many contractors for exterior work. Polyurethanes provide excellent adhesion to a wide variety of materials from wood to masonry and remain flexible across a wide temperature range. Furthermore, they are relatively easy to tool, and some brands accept wet tooling with soapy water. Tooling time is adequate and shrinkage minimal. Polyurethanes are available in only a few colors, but the cured sealant holds paint well. Although polyurethane is not naturally UV-resistant, UV inhibitors give it good durability in exterior applications. Because of its aggressive bond, polyurethanes are good for sealing between different materials. Polyurethanes are widely used on metal roofs, concrete and masonry control joints, flashing, and exterior trim. OSI Sealants, (Mentor OH, 800-999-8920) produces urethane caulks. Guide to Using Butyl Caulks & Sealants on buildingsButyl is a high-quality, tough, rubber like sealant that is ideal for exterior jobs requiring a durable, watertight seal. Because of its longevity, temperature range, and high UV resistance, it has long been used as a glazing compound. Notable for its stickiness, butyl bonds very well to a wide range of materials, including wood, concrete, masonry, glass, and metal. Its stickiness, however, can also make its application messy and tooling difficult. Before curing, it can be cleaned with mineral spirits. Because of its good adhesion and water resistance, butyl is often used to seal metal gutters, metal roofing, and around foundations. It is approved for use below grade. Butyl should not be used, however, in contact with modified-bitumen flashing tapes or roofing membranes, which can degrade it. Guide to Using Acrylic Latex Caulks & SealantsThe most economical and widely used caulking compound in residential work, acrylic latex caulks come in a wide variety of formulations and prices. To their credit, latex caulks are easy to apply, easy to tool, and can be cleaned before curing with water. They bond moderately well to a wide variety of materials and have a long tooling time. When cured they are highly paintable, making acrylic latex popular for caulking paintable trim in both the interior and exterior. Lower-end acrylic latex caulks do not have the same flexibility, temperature range, and long-term durability as butyl, polyurethane, or silicone. Newer premium products, however, promise performance on par with some of the high-performance sealants. Added plasticizers make the material more flexible and other additives provide better UV and water resistance. For exterior work in joints subject to movement, look for an ASTM C920 rating and a rated joint movement of +/1 25%. Most latex caulks cannot be applied under 40°F and should not be allowed to freeze in the tube or in place before cured. Also do not apply to wet surfaces or where rain is likely to fall before the caulk has a chance to fully cure. Choosing a Caulking Gun for Easy Fast Caulking Work & Good ResultsDetails about choosing a caulk gun are at CAULK GUN TYPES, CHOICES. Excerpts are below. 
Resources for Building Exterior Caulks and SealantsConstruction Sealant (Caulks) Suppliers & ProductsAlbion, 1250 North Church Street, Moorestown, New Jersey 08057-1102 http://www.albioneng.com/, 856-235-6688 Chemrex www.chemrex.com Newborn caulking guns, distributed by Jamestown JD Distributors - http://www.jamestowndistributors.com Polyurethanes and other high-performance sealants3M - 800-234-8068 Bostik - Chem-Calk urethane caulk - 414-774-2250 DAP www.dap.com - 800-543-3840 Tremco - Velcum urethane caulk - 800-321-7906 Macklanburg-Duncan - Sika and Sikaflex caulks - 800-654-8454 (widely used in sealing concrete wall and floor slab cracks in the radon mitigation industry) OSI Sealants These companies produce urethane caulks used widely on masonry surfaces and in the automotive industry. Acrylic latex caulksDow Corning Sealants www.dowcorningsealants.com Silicone sealants GE Silicones www.gesilicones.com Silicone sealant Geocel Corp www.geocelusa.com Acrylic latex, tripolymer, copolymer, Kraton, and clear sealants Macklanburg-Duncan www.mdteam.com Acrylic latex sealants OSI Sealants Inc www.osisealants.com Polyseamseal PVA-based caulk. Pro Series includes latex, polyurethane, and Kraton sealants. www.phenoseal.com Phenoseal vinyl adhesive caulk Red Devil www.reddevil.com Acrylic, silicone, and butyl sealants Sashco Sealants www.sashco.com Big Stretch and Mor-Flexx water-based sealants, Lexel Kraton sealant Sika Corp www.sikaconstruction.com Complete line of Sikaflex polyurethane-based sealants, butyl sealant Tremco Inc. www.tremcosealants.com High-performance, architectural-grade sealants, UGL www.ugl.com Acrylic latex caulks White Lightning www.wlcaulk.com Tripolymer, butyl, polyurethane, silicone, elastomeric, and other high-performance sealants Exterior AdhesivesAbatron EpoxyWood Repair/Restoration 5501 - 95th Avenue, Kenosha, WI 53144 USA Tel: (262) 653-2000
Fax: (262) 653-2019, For orders: (800) 445-1754 Abatron provides a wide range of wood & building restoration epoxy products including a low-viscosity system that penetrates and solidifies rotted wood and a thicker wood repair putty type epoxy. Ambel www.excelglue.com Excel polyurethane glue Elmer’s Products www.elmers.com Yellow glues, ProBond polyurethane glue Custom-Pak Adhesives www.custompak.com Resorcinol and yellow glues DAP Inc. www.dap.com Weldwood contact cement, resorcinol, and construction adhesives Resources 49 Franklin International www.titebond.com Titebond yellow glue, Liquid Hide Glue, and construction adhesives Gloucester Co. Inc. www.phenoseal.com Phenoseal adhesive caulk Gougeon Brothers www.westsystem.com West System epoxy Gorilla Group www.gorillaglue.com Gorilla polyurethane glue MACCO Adhesives www.liquidnails.com Liquid Nails construction adhesive SI Sealants www.osisealants.com PL400 construction adhesive System Three Resins www.systemthree.com Quick Cure epoxy -- Adapted with permission from Best Practices Guide to Residential Construction. Questions & Answers regarding this article. Ask a Question or Search InspectAPediaHTML Comment Box is loading comments...
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