Detailed Inspection & Photo Guide to inspecting for chimney defects in the building interior
Chimney defects discovered in building attics
Signs of holes and unsound masonry chimneys
Significance of creosote or other stains on chimneys
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This article describes procedures for inspecting the condition of chimneys and flues from inside of a building. We begin in the building attic (or on the building's highest floor) and continue downwards through the building with text and photographs describing chimney damage or chimney hazards for which the building owner, inspector, or service technician should be alert.
Interior basement and attic inspections will reveal corrosion at the
cleanout door, connector problems and flashing leaks.
Inspect exterior the chimney while you are inside the building. Attic access
to a chimney or basement access, may provide key inspection points since there the
chimney is likely to be directly accessible and there may be cleanout or other
access ports to check the condition of the chimney interior.
In this photo the exterior of this chimney, visible in an attic, was in very
poor condition, with soft spalling bricks.
Worse, there was an immediate fire and
gas hazard since there were actual openings at the base of this chimney where
it passes through the attic floor framing. This is a serious fire hazard and
a flue gas leak hazard. This flue is unsafe.
Inspect the entire route of the chimney through all building areas. Even if the
chimney is not directly visible you may find evidence of leaks, movement, or
old chimney penetrations, say for a woodstove, that may not have been safely closed.
Holes in Masonry Chimneys - Missing Bricks
Missing chimney bricks: this photo shows a homeowner "repair" involving
putting aluminum sheet metal over a hole in their chimney to make it "safe" -
removing the metal disclosed a nice hole where bricks were missing. We asked the
homeowner where s/he thought those bricks had gone?
This was a very unsafe chimney.
The second photo shows the chimney hole with the sheet metal removed.
The bricks had fallen down and blocked this flue, creating a potentially fatal carbon monoxide (CO Gas) hazard which was first noticed by the homeowners as a basement water problem - water was condensing and running down basement walls.
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Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, 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
More Information on Building Diagnostic Inspections and Repairs
Chimney Building Codes and Chimney, Flue, and Appliance Venting Standards
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
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
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