CHIMNEY SPALLING - CONTENTS: What causes spalling or loss of brick or masonry block surface material from a chimney?Significance of chimney spalling on its exterior. Leaks at chimney shoulders damage building walls & interiors & invite insect pests & rot
POST a QUESTION or READ FAQs about the causes and hazards of spalling, flaking, chipping (or cracking) of masonry flues.
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Spalling damage on masonry chimneys: This article defines chimney spalling and describes the causes and significance of spalling on masonry chimney exteriors. We show examples of different types of brick spalling or concrete block spalling ("cinder block spalling") damage and we explain its causes.
Causes, Impact & Repair of Spalling Chimney Exterior Surfaces
Spalling describes the chipping off or loss of surface from a masonry material. Spalling can occur on a brick chimney such as the one shown at left, on masonry block chimneys, and on other masonry surfaces such as sidewalks or foundation walls. The chimney is also "supported" by a metal strap tying it to the home.
[Click to enlarge any image]
In our photo at above left you can see that leaks at the chimney top from an improperly sealed chimney crown have sent water into the chimney structure. Not only has the face broken away from some of the bricks, leaving their softer interior exposed to the weather, but also bricks have been dislocated and are being pushed off of the chimney.
Spalling can occur even in warm climates when a masonry product is soft, porous, improperly made, or improperly constructed. But spalling damage is often most severe in northern climates where a freeze-thaw cycle can cause frost to actually break and push off masonry fragments.
Our photo at left shows typical brick chimney spalling - notice that ultimately entire bricks can be lost leaving a hole in the chimney and accelerating water and frost damage.
We sometimes find bricks have been lost entirely from a chimney and we have to ask if the bricks fell into the flue (blocking it and making it unsafe). Our photo at above right shows a spalling concrete block chimney.
A spalled chimney may also have a damaged and unsafe flue.
A detailed inspection of the flue interior is in order. But usually spalling and frost damage occur only on the exterior portions of a chimney exposed to weather, not on the interior portions that run inside of a building.
Watch out: water and frost damage to masonry chimneys can lead to costly damage, fire and flue gas hazards, and even chimney collapse hazards. See Chimney Crack & Collapse
This spalling and cracked masonry chimney exterior was observed near Sharon Ct. and illustrates leaks into and thorugh the chimney structure.
Notice the brown stains exuding from the chimney face about 12 feet below the chimney top? That's a sure indication of water and condensate leaking from the chimney interior out through the masonry structure of the chimney.
The flues in this chimney need to be inspected for safety and the chimney top cap repaired.
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides:
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Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Contact Mark Cramer at: 727-595-4211 mark@BestTampaInspector.com 11/06
Roger Hankey is principal of Hankey and Brown home inspectors, Eden Prairie, MN. Mr. Hankey is a past chairman of the ASHI Standards Committee. Mr. Hankey has served in other ASHI professional and leadership roles. Contact Roger Hankey at: 952 829-0044 - rhankey@hankeyandbrown.com. Mr. Hankey is a frequent contributor to InspectAPedia.com.
Arlene Puentes, an ASHI member and a licensed home inspector in Kingston, NY, and has served on ASHI national committees as well as HVASHI Chapter President. Ms. Puentes can be contacted at ap@octoberhome.com
[5] Stephen Werner, General Manager, Chimney King LLC., P.O. Box 8, Gurnee, IL 60031, Tel: (847) 244-8860, Email: steve@chimneyking.com, Website: www.chimneyking.com . Mr. Werner is also a licensed home inspector serving clients in Wisconsin.
[6] Residential Masonry Fireplace and Chimney Handbook, James E. Amrhein, S.E., MIA, Masonry Institute of America, 2d. Ed., 1995, ISBN 0-940116-29-4. The MIA is in Los Angeles, CA 213-388-0472. This manual reflects the 1994 Uniform Building Code, Energy Conservation Requirements of California, and the U.S. Department of Housing and Urban Development - HUD. The complete UBC is available from the International Conference of Building Officials (ICBO), Whittier CA 310-699-0541.
[7] NFPA 211 - Standards for Chimneys & Fireplaces, NFPA 211: Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances, 2006 Edition (older editions and standards are found at the same bookstore)
[8] NFPA 211 - Standards for Chimneys & Fireplaces, NFPA 211: Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning Appliances, 2006 Edition (older editions and standards are found at the same bookstore), NFPA #211-3.1 1988 -
Specific to chimneys, fireplaces, vents and solid fuel burning appliances.
NFPA 211 - 3-1.10 - Relining guide for chimneys
NFPA 211 - 3-2 - Construction of Masonry Chimneys
NFPA 211 - 3-3 - Termination Height for chimneys
NFPA 211 - 3-4 - Clearance from Combustible Material
NFPA 54 - 7-1 - Venting of Equipment into chimneys
[9] NFPA # 54-7.1 1992 -
Specific to venting of equipment with fan-assisted combustion systems.
[10] GAMA - Gas Appliance Manufacturers' Association has prepared venting tables for
Category I draft hood equipped central furnaces as well as fan-assisted
combustion system central furnaces.
[11] National Fuel Gas Code, an American National Standard, 4th ed. 1988 (newer edition is available) Secretariats, American Gas Association (AGA), 1515 Wilson Blvd., Arlington VA22209, and National Fire Protection Association (NFPA), Batterymarch Park, Quincy MA 02269. ANSI Z223.1-1988 - NFPA 54-1988. WARNING: be sure to check clearances and other safety guidelines in the latest edition of these standards.
[12] Fire Inspector Guidebook, A Correlation of Fire Safety Requirements Contained in the 1987 BOCA National Codes, (newer edition available), Building Officials and Code Administrators International, Inc. (BOCA), Country Club HIlls, IL 60478 312-799-2300 4th ed. Note: this document is reissued every four years. Be sure to obtain the latest edition.
[13] Uniform Mechanical Code - UMC 1991, Sec 913 (a.) Masonry Chimneys,
refers to Chapters 23, 29, and 37 of the Building Code.
[14] New York 1984 Uniform Fire
Prevention and Building Code, Article 10, Heating, Ventilating, and Air Conditioning Requirements
New York 1979 Uniform Fire Prevention & Building Code, The "requirement" for 8" of solid masonry OR for use of a
flue liner was listed in the One and Two Family Dwelling Code for New
York, in 1979, in Chapter 9, Chimneys and Fireplaces, New York 1979
Building and Fire Prevention Code:
[15] "Top Ten Chimney (and related) Problems Encountered by One Chimney Sweep," Hudson Valley ASHI education seminar, 3 January 2000, contributed by Bob Hansen, ASHI
[17] "Rooftop View Turns to Darkness," Martine Costello, Josh Kovner, New Haven Register, 12 May 1992 p. 11: Catherine Murphy was sunning on a building roof when a chimney collapsed; she fell into and was trapped inside the chimney until rescued by emergency workers.
[18] "Chimneys and Vents," Mark J. Reinmiller, P.E., ASHI Technical Journal, Vol. 1 No. 2 July 1991 p. 34-38.
[19] "Chimney Inspection Procedures & Codes," Donald V. Cohen was to be published in the first volume of the 1994 ASHI Technical Journal by D. Friedman, then editor/publisher of that publication. The production of the ASHI Technical Journal and future editions was cancelled by ASHI President Patrick Porzio. Some of the content of Mr. Cohen's original submission has been included in this more complete chimney inspection article: InspectAPedia.com/chimneys/Chimney_Inspection_Repair.htm. Copies of earlier editions of the ASHI Technical Journal are available from ASHI, the American Society of Home Inspectors.
[20] Natural Gas Weekly Update: http://tonto.eia.doe.gov/oog/info/ngw/ngupdate.asp Official Energy Statistics from the U.S. Government
[21] US Energy Administration: Electrical Energy Costs http://www.eia.doe.gov/fuelelectric.html
[24] Ceramic Roofware, Hans Van Lemmen, Shire Library, 2008, ISBN-13: 978-0747805694 - Brick chimneys, chimney-pots and roof and ridge tiles have been a feature of the roofs of a wide range of buildings since the late Middle Ages. In the first instance this ceramic roofware was functional - to make the roof weatherproof and to provide an outlet for smoke - but it could also be very decorative.
The practical and ornamental aspects of ceramic roofware can still be seen throughout Britain, particularly on buildings of the Victorian and Edwardian periods. Not only do these often have ornate chimneys and roof tiles but they may also feature ornamental sculptures or highly decorative gable ends. This book charts the history of ceramic roofware from the Middle Ages to the present day, highlighting both practical and decorative applications, and giving information about manufacturers and on the styles and techniques of production and decoration.
Hans van Lemmen is an established author on the history of tiles and has lectured on the subject in Britain and elsewhere. He is founder member and presently publications editor of the British Tiles and Architectural Ceramics Society. Also available at the InspectAPedia Bookstore.
[26] Chimney & Stack Inspection Guidelines, American Society of Civil Engineers, 2003 - These guidelines address the inspection of chimneys and stacks. Each guideline assists owners in determining what level of inspection is appropriate to a particular chimney and provides common criteria so that all parties involved have a clear understanding of the scope of the inspection and the end product required. Each chimney or stack is a unique structure, subject to both aggressive operating and natural environments, and degradation over time. Such degradation may be managed via a prudent inspection program followed by maintenance work on any equipment or structure determined to be in need of attention. Sample inspection report specifications, sample field inspection data forms, and an example of a developed plan of a concrete chimney are included in the guidelines. This book provides a valuable guidance tool for chimney and stack inspections and also offers a set of references for these particular inspections.
[31] Brick Institute of America - Flashing Chimneys
Brick Institute of America - Proper Chimney Crowns
Brick Institute of America - Moisture Resistance of Brick
[32] American Gas Association - New Vent Sizing Tables
[33] Chimney Safety Institute of America - Chimney Fires: Causes, Effects, Evaluation
[34] National Chimney Sweep Guild - Yellow Pages of Suppliers
[35] "Building Codes that Regulate Decorative Chimney Shrouds", provided by Stephen Werner [5], [copy on file as Chimney_Decorative_Shroud_Regs.pdf] cites:
International Mechanical Code IMC (2000), M74-98 806.6, ratified 9.98, model building code for the United States,
806.6 Decorative Shrouds. Decorative shrouds shall not be installed at the
termination of factory-built chimneys, except where such shrouds are listed
and labeled for use with the specific factory-built chimney system and are
installed in accordance with section 304.1.
Reason: Decorative shrouds have been the cause of roof and chase fires
International Residential Code (IRC) (2000), R1002.2 ratified 9/99, 1000.2 Decorative Shrouds. Decorative shrouds shall not be installed at the
termination of factory-built chimneys, except where such shrouds are listed
and labeled for use with the specific factory-built chimney system and are
installed in accordance with the manufacturers installation instructions.
Reason: Decorative shrouds often allow for the creation of temperatures in
excess of those permitted in UL 103 and UL 127. Decorative shrouds have
been the cause of chase top fires ...
International Fire Code (IFC) (2000), IFC 603.6.3, 603.6.3 Decorative Shrouds. Decorative shrouds installed at the
termination of factory-built chimneys shall be removed, except where such
shrouds are listed and labeled for use with the specific factory-built
chimney system and are installed in accordance with the manufacturers
installation instructions.
Reason: Decorative shrouds have been the cause of dozens of chase fires.
As a non-listed part to a listed assembly, their use should not have been
allowed in the first place.
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