SAVE THE WALL!
Transcription
SAVE THE WALL!
ask the expert BY JAMIE FARNY How Can Efflorescence Be Minimized in New Masonry Buildings Photos courtesy of the Portland Cement Association Efflorescence is a crystalline deposit, usually white, that may develop on the surfaces of masonry construction. Sometimes it appears just after the structure is completed and is termed new building bloom. Deposits from efflorescence are less noticeable on lighter-colored surfaces than on darker-colored surfaces. Although unattractive, efflorescence is generally harmless, temporary and decreases with the passage of time. Recurrent efflorescence indicates a chronic moisture problem, which should be corrected. Efflorescence is often called new building bloom because it appears on fresh masonry surfaces. A combination of three common circumstances causes efflorescence: • soluble compounds (salts) in the masonry or adjoining materials • moisture to pick up the soluble compounds and carry them to the surface • evaporation or hydrostatic pressure that causes the solution to move If any one of these conditions is eliminated, efflorescence will not occur. All masonry and concrete materials are susceptible to efflorescence, so a materialbased approach to controlling it is ineffective. During construction, moisture sources include water used to achieve a workable mortar or flowable grout, rain and snow. Efflorescence is affected by temperature, humidity and wind. Usually efflorescence is more common in the winter when a slower rate of evaporation allows migration of salts to the surface. Restoration Team Experience Since 1978 Masonry Façade Re-Anchoring Solutions SAVE THE WALL! Don’t Tear it Down or Cover it with Insulation and Stucco Strengthen and stabilize masonry façades while adding veneer stiffness for added decades of protection and comfort. CTP has engineered anchor performance solutions for claddings of brick and stone. A selection of corrosion resistant products is available to re-anchor brick to wood, concrete, steel, block, brick, metal stud, or tile back-ups. Stitch-Tie Panel-Tie Helical Wall Tie System for Stabilizing Veneers and Crack Repair Mechanical Anchors for Stabilizing Stone Panel Veneers Construction Tie Products, Inc. is committed to supplying the highest quality masonry tie and construction systems in North America and satisfying all stringent national codes and standards for today's building structures. CTP, Inc. promises to be a reliable product source along with on-time business integrity for all demanding builders. Torque-Tie Mechanical Repair Anchors for Stabilizing Veneers Contact our Technical Services Team with your repair application needs for a cost effective and performance targeted veneer stabilizing solution. Proudly Made In the USA! 30 the story pole JULY/AUGUST 2006 7974 W. Orchard Drive Michigan City, Indiana 46360-9390 USA Phone: (219) 878-1427 www.ctpanchors.com Engineered Anchoring Solutions Provider The top of masonry walls should be protected with a tarp whenever rain or snow is expected. It is good practice to cover work at the end of each day to help keep excessive water out and aid curing. THE DRY-BLOCK® SYSTEM FOR CONCRETE MASONRY WALLS One Time-Proven Solution for Moisture Control DRY-BLOCK® BLOCK ADMIXTURE DRY-BLOCK® MORTAR ADMIXTURE In most cases, salts that cause efflorescence come from beneath the surface. Hydrated portland cement contains a substantial amount of calcium hydroxide, as a product of the reaction between cement or lime and water. Calcium hydroxide, brought to the surface by moisture, combines with carbon dioxide in the air to form calcium carbonate, which then appears as a whitish deposit often referred to as a lime deposit. Since calcium hydroxide is much more soluble in cold water than warm water, such deposits are more common in winter than summer. Many factors influence the formation of efflorescence, so it is difficult to predict if and when any will appear. It is virtually impossible to eliminate all the soluble compounds, construct walls containing no free moisture, or completely eliminate paths of moisture migration. Therefore, good workmanship is one of the most effective means of limiting the potential for efflorescence. The following steps can be taken to minimize efflorescence. Good drainage: • Limit entry of water and provide for its removal by using waterstops, flashing, weepholes and copings. Maintain clean cavities and unobstructed weepholes. Good mortar joints: • Tool all mortar joints with a concave- or V-shaped jointer to compact the mortar and create a tight bond between mortar and masonry unit. Weeping, raked and untooled struck joints are not recommended in exposed applications. • Ensure that joints are properly filled, and repair or repoint deteriorated or defective mortar joints. • Provides water-repellent blocks and mortar • Improves mortar bond strength • Unaffected by time or weathering www.DryBlock.com • • • • Product data sheets Information on best practices in masonry construction NCMA TEK Bulletins CAD detail drawings CONTACT YOUR QUALIFIED DRY-BLOCK PRODUCER: 4-D, Inc. Midland, MI 989-631-0400 www.4dblockandbrick.com Bark River Concrete Bark River, MI 906-466-9940 Fendt Builders Supply Farmington Hills, MI 248-474-3211 www.fendtproducts.com Fraco, Inc. Marquette, MI 906-249-1476 www.fracoinc.com Michigan Certified Concrete Products, Inc. Grand Rapids, MI 616-241-4461 www.micertconcrete.com Miller Products Iron Mountain, MI 906-774-1243 Superior Block Company Houghton, MI 906-482-2731 www.superiorblock.com The Concrete Service Inc. Traverse City, MI 231-946-7880 www.theconcreteservice.com or contact Dennis Hayes, Grace Masonry Representative: 414-870-0939 www.graceconstruction.com DRY-BLOCK is a registered trademark of W.R. Grace & Co.-Conn. EFFICIENT DESIGN INC. MASONRY SPECIALIST / GENERAL CONTRACTOR Seminole Academy, Mt. Clemens Courtesy of French Associates Raymond Saelens, President 586-598-0055 51935 North Gratiot Chesterfield, MI 48051 PROUD MASON CONTRACTOR FOR THE SEMINOLE ACADEMY JULY/AUGUST 2006 the story pole 31 ask the expert Since 1929, Halquist Stone Co., Inc. has been quarrying throughout Wisconsin in Lannon, Chilton, Fond du Lac and central Wisconsin. NOW QUARRYING in the UPPER PENINSULA, we offer you our new Bay de Noc™ Limestone!!! Available in many blends, this unique, local stone from Michigan is available in thin and full weight veneer. When you think stone, think Halquist Stone, we have it all! Bay De Noc TM LIMESTONE Contact A Dealer Near You. Beaver Tile & Stone Farmington Hills • 248-476-2333 Rochester Hills • 248-299-8100 Grand Rapids • 616-534-2883 Troy • 248-649-5552 Saginaw • 989-790-5851 Lincoln Brick & Stone Saginaw • 989-692-7425 Dearborn • 313-582-1760 Grand Rapids • 616-452-6055 Bosker Brick Company, Inc. Battle Creek • 616-968-8181 Sackett Brick Kalamazoo • 616-381-4757 Capital Stoneworks Vassar • 989-823-9466 Statler Concrete & Supply Kalamazoo • 269-345-7105 Darling Builders Supply Company, Inc. Lansing • 517-484-5707 Stone City/Soulliere Decorative Stone Utica • 586-731-3947 Dwyer Marble & Stone Farmington Hills/Detroit 248-476-4944 The Concrete Services, Inc. Traverse City • 231-946-7880 Genesee Cut Stone Flint • 810-743-1800 Lansing • 517-485-7224 Positive Chimney & Fire Place Cadillac • 231-775-7941 West Friendship Materials, Inc. Detroit • 313-838-6000 8 0 0 - 2 5 5 - 8 8 1 1 www.halquiststone.com 32 the story pole JULY/AUGUST 2006 Proper curing: • Ensure adequate hydration of cementitious materials by protecting masonry from cold temperatures or premature drying. Limited water entry: • Apply paint or other proven protective treatment to the outside surfaces of absorptive masonry units. Caulk around window and door openings. Seal or otherwise repair cracked joints in walls. Also, use through-wall flashing at ground level to prevent capillary rise of ground moisture. • Install vapor barriers in exterior walls or apply vaporproof paint to interior surfaces and use designs that minimize condensation within masonry. • Carefully plan the installation of lawn sprinklers so that walls are not subjected to unnecessary wetting. • If feasible, use wide overhanging roofs to protect walls from rain. Limited driving forces: • Provide for pressure equalization between the outside and the void within the masonry wall by appropriate venting of cavities. To reduce the potential for efflorescence associated with new construction, the following steps may be taken to limit the moisture introduced into the wall during construction. • Keep masonry units stored at job site covered and on pallets placed in well drained locations. • Cover the top course of masonry at the completion of each day’s work, particularly when rain (or snow) is expected. • Use washed ASTM C144 sand. • Don’t use units known to effloresce while stockpiled. • Use clean mixing water free from harmful amounts of acids, alkalies, organic material, minerals and salts. • Use insulating material free of salts when walls of hollow masonry units are to be insulated by filling the cores. • Be certain that mixer, mortar box, mortarboards and tools are not contaminated or corroded. Never de-ice this equipment with salt or antifreeze material. • Use mortar materials (cements or admixtures) of lower alkali content. Inspired by Mother Nature Engineered by Advanced Remember how much fun it was to play in the rain when you were a kid? No matter how hard the drops fell or how deep the puddles were, your boots and umbrella kept you dry as can be. You were invincible. At Advanced Building Products, it’s our mission to provide your next construction project with even greater waterproof integrity. For a complete list of flashing products that keep storm water at bay, go to www.advancedflashing.com CONCEALED MASONRY FLASHINGS COPPER FABRIC FLASHING COP-R-KRAFT DUPLEX CONCEALED WOOD FRAME FLASHINGS COPPER SEALTITE 2000 COP-R-CORNER PEEL-N-SEAL MORTAR BREAK AND ACCESSORIES Given time, efflorescence will often disappear by itself or at most may require mild cleaning measures such as dry brushing or rinsing and brushing with a stiff brush. If this does not produce satisfactory results, it may be necessary to clean the surface by chemical methods. See the reference for further information about cleaning. Jamie Farny is PCA’s program manager of Masonry and Special Products, coordinating research and promotion activities regarding cements for masonry and white cement. He participates on committees on concrete, plastering, mortars and masonry units of the American Society for Testing and Materials (ASTM) and the American Concrete Institute (ACI). He holds a B.S. degree in civil engineering from the Illinois Institute of Technology. REFERENCE Trowel Tips: Efflorescence, IS239, Portland Cement Association, Skokie, IL, 2004, 4 pages. Free download at: www.cement.org/bookstore COP-R-KRAFT COP-R-SHIELD YOUR #1 SOURCE FOR COPPER FLASHINGS AND MASONRY ACCESSORIES MORTAR BREAK II [F] MORTAR MAZE CELL VENTS 800.252.2306 207.490.2306 207.490.2998 www.advancedflashing.com MORTAR BREAK