Repair Methods for Ongoing Chimney Movement, Leaning Chimneys InspectAPedia® -
List of repair alternatives for chimney separation or movement that is ongoing and a major problem
Leaning, separated or cracked chimneys; missing chimney supports
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This article describes the common repair methods used to handle a chimney which is leaning, cracked, or separating from a building. We outline common repair methods used to stabilize loose or leaning chimneys.
This website provides detailed suggestions describing how to perform a thorough visual inspection of chimneys for safety and other defects. Chimney inspection methods and chimney repair methods are also discussed. As with most inspection and safety topics, this material may be incomplete.
As we cited earlier at Chimney Movement is Ongoing - Evidence, sometimes
we see a chimney that has been "repaired" in this manner several times, with several
generations of concrete or caulk or wood trim strips. Our closeup photo at the top of this page showed a wide concrete patch between a chimney and the building. Often we see thick build-up of roofing mastic where a chimney has moved at the edge of a building roof..
In both photos below, a wide metal strip has been fabricated to cover the gap that has opened between the chimney and the building (below right) and a heavy metal strap has attempted to "bolt" the chimney to the home (below left, also visible at the upper chimney section (below right).
Why is this chimney strapping repair alone probably inadequate?
If the chimney is settling because of an inadequate footing, it is unlikely that this repair will succeed. On occasion we've seen the mass of a heavy chimney actually pull the building wall along with it as it settled and tipped further.
The chimney flue interior is likely to be damaged and unsafe
The fireplace box, hearth, and support are likely to be damaged and unsafe
What could have been done to repair the chimney shown above?
Confirm that the defect is due to a bad chimney footing, stabilize the footing using slab-jacking or helical piers
Re-line the damaged chimney flue
Align, stabilize, and repair cracks in the fireplace box and hearth
Alternatively
Remove the chimney entirely, then construct a new chimney on a proper footing
Abandon the chimney entirely, stabilize and leave it in place, provide alternative chimneys to vent the home heating appliances using a manufactured chimney elsewhere on the building
Abandon the chimney entirely, convert the heating boiler or furnace to a high-efficiency direct-vent unit.
Which of these alternatives makes most sense depends on other factors such as the condition of the heating equipment and the desire to have a traditional masonry fireplace.
A Summary of Leaning Chimney Repair Methods
Strapping a masonry chimney to the building in an attempt to stabilize a tipping or leaning chimney it is unlikely to work, especially if the root cause of chimney movement is an inadequate or tipping chimney foundation. The total weight or mass of a masonry chimney is enormous. Trying to hold this weight in place by strapping the flue to the building structure risks bending or moving the structural wall in many instances. (If a chimney has a sound footing or a soundly-repaired footing and is to be tied to the building as a retrofit repair, the building tie-in may need to pass through the building rather than just being connected to the building wall abutting the chimney.)
It is normal to tie a masonry chimney to the building to prevent movement. Those ties, if present, are likely to be hidden between the chimney side facing the building and the building wall itself. That lateral chimney support stabilizes a chimney that has a sound footing. But lateral support cannot normally stabilize a chimney whose footing is missing or tipping.
Chimney foundation repairs: If a leaning chimney is relatively un-damaged, and if the movement is traced to ongoing chimney foundation settlement, it might be possible to use helical piers, driven pins, or other foundation repair methods to repair the chimney.
Flue relining a moving chimney: Some chimney repair companies may suggest stabilizing a chimney flue that has moved, followed by installation of a flue liner in order to assure that the flue is fire and gas safe.
Fireplace movement: If you are considering this repair be sure that your mason and chimney company inspect any fireplaces carefully. we have observed movement and cracking in the firebox which made the fireplace and hearth serious fire hazards themselves, independent of questions about the safety of the chimney flue. See Fireplace Safety Hazards below.
Chimney reconstruction: if the chimney has moved more than a very small amount, perhaps less than 3/16", some chimney repair companies may suggest that the chimney should be disassembled and rebuilt correctly. That is because they are worried that internal cracks in the masonry flue have made the chimney a flue gas and fire hazard.
Certainly if a chimney has moved significantly away from a building it is almost certainly dangerous, risking a building fire and flue gas leakage.
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Additional technical contributors & reference sources for this article are listed below.
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Carson Dunlop, Associates, 120 Carlton Street Suite 407, Toronto ON M5A 4K2Toronto. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. Thanks to Alan Carson and Bob Dunlop, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education including the ASHI-adopted Home Inspection Training Program (home study course), publications such as the Home Reference Book, report writing materials including the Horizon report writer, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Thanks to Luke Barnes for suggesting that we add text regarding the hazards of shared chimney flues. USMA - Sept. 2008.
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
Roger Hankey is principal of Hankey and Brown home inspectors, Eden Prairie, MN, technical review by Roger Hankey, prior chairman, Standards Committee, American Society of Home Inspectors - ASHI. 952 829-0044 - hankeyandbrown.com
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 # 54-7.1 1992 -
Specific to venting of equipment with fan-assisted combustion systems.
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.
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.
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.
Uniform Mechanical Code - UMC 1991, Sec 913 (a.) Masonry Chimneys,
refers to Chapters 23, 29, and 37 of the Building Code.
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:
"Top Ten Chimney (and related) Problems Encountered by One Chimney Sweep," Hudson Valley ASHI education seminar, 3 January 2000, contributed by Bob Hansen, ASHI
"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.
"Chimneys and Vents," Mark J. Reinmiller, P.E., ASHI Technical Journal, Vol. 1 No. 2 July 1991 p. 34-38.
"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.htm. Copies of earlier editions of the ASHI Technical Journal are available from ASHI, the American Society of Home Inspectors.
Natural Gas Weekly Update: http://tonto.eia.doe.gov/oog/info/ngw/ngupdate.asp Official Energy Statistics from the U.S. Government
US Energy Administration: Electrical Energy Costs http://www.eia.doe.gov/fuelelectric.html
Books & Articles on Chimney Inspection, Testing, Diagnosis, & Repair
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. Available at the InspectAPedia Bookstore.
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.
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)
More Information on Building Diagnostic Inspections and Repairs
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
Brick Institute of America - Flashing Chimneys
Brick Institute of America - Proper Chimney Crowns
Brick Institute of America - Moisture Resistance of Brick
American Gas Association - New Vent Sizing Tables
Chimney Safety Institute of America - Chimney Fires: Causes, Effects, Evaluation
National Chimney Sweep Guild - Yellow Pages of Suppliers
InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.
The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems
Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.
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