Fireplace mantel collapse (C) Daniel Friedman Fireplace & Hearth Damage, Cracks, Settlement or Collapse
Inspection & Repair of Damaged Fireplaces & Hearths

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Fireplaces & hearth damage, cracks, settlement, & other fire hazards:

This article describes masonry fireplace damage, cracks, settlement, and fire hazards and suggests inspection points and some repair procedures. We also link to other fireplace and chimney-fire safety articles and advice. At page top: our photo shows the collapse into the room of a poorly-secured wood frame around a masonry fireplace.

This article series provides information about masonry fireplaces, including inspection for damage/hazards (cracks and gaps that appear at masonry fireplaces due to chimney or fireplace settlement or movement), fireplace chimney sizing requirements, draft problems, chimney safety, creosote problems, inserts, and other topics.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Masonry Fireplace Specifications, Safety Hazards, Recommendations

Fireplace burned floor (C) Daniel Friedman

[Click to enlarge any image]

Article Contents:

Watch out: while this article discusses fireplace dangers & fire risks related to cracks or settlement in the fireplace chimney, the most common fire hazard associated with fireplaces is a chimney fire caused by the ignition of accumlulated creosote in the fireplace chimney flue.


Fireplace Damage and Unsafe Hearths due to Chimney or Fireplace Settlement

Fireplace schematic

Why are gaps at fireplace fireboxes, hearths, or other components a dangerous fire hazard? What should you do about them?

Do not use a fireplace that is in any doubt about safety before it has been inspected by a professional. Our photo (above) shows a fireplace mantel that collapsed and fell into the room. Smoke stains revealed on the brick might point to a chimney draft problem too.

The fireplace schematic (above) shows the basic components of a masonry fireplace and their names. This drawing is obsolete in that it is missing a combustion air supply for the fireplace.

These articles on chimneys and chimney safety provide 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.

Carson Dunlop Associate's sketch given below shows a cross section of the basic components of a chimney where a fireplace is installed. Carson Dunlop Associates is a Toronto home inspection & education firm.

Parts of a fireplace and chimney - schematic (C) Carson Dunlop Associates

[Click to enlarge any image]

Beginning with the outside inspection of the chimneys and structure, and continuing indoors, we check for a wide range of possible chimney hazards. Among these are issues surrounding chimney movement, settlement, or separation from the building.

Too often we discover that a building owner was aware that a chimney has moved, s/he has patched the gap between the chimney and the building, but s/he has not realized that the movement causes cracks and gaps inside the chimney or fireplace which are very dangerous.

Below we provide three photographs showing how a fireplace can become a fire hazard due to chimney settlement or inadequate support of the fireplace itself.

We start with a look at the fireplace hearth for evidence of movement.

Caulk is Not a Safe Repair for Hearth Settlement

Fireplace settlement crack at floor (C) Daniel Friedman

In an easy-to-spot case of movement and separation between a fireplace hearth and the building floor take a look at the white caulk installed in an open crack between the hearth face and the floor in our photo (left).

A bit more investigating was needed to determine whether the floor was sagging away from a stable masonry fireplace and chimney or whether the chimney and entire firebox were leaning away from the building.

Cracks Can Show Settlement of The Fireplace Fire-Box and Chimney OR Hearth Settlement

In the next case, just below, the gaps and cracks made it obvious that the chimney and fireplace were tipping away from the building in a dangerous condition.

Fireplace settlement and cracks (C) Daniel Friedman Fireplace settlement and cracks (C) Daniel Friedman

First at above left we see a gap that has opened up between the fireplace floor and the hearth (above-left). Sparks may fall into this space, causing a building fire.

Second (above right) our photo shows a crack between the face of the fireplace and the fireplace box itself. We don't know without more analysis whether the brick facing has fallen away from a sound and safe fireplace or whether the fireplace has moved away from the facing.

Cracks & Gaps Mean an Unsafe Fireplace

Dangerous crack inside the fireplace chimney throat (C) Daniel Friedman

Our third fireplace damage photograph (above) is the final nail in the coffin of this unfortunate fireplace.

A gap has opened in the fireplace below the chimney where the damper was cemented in place. There has been substantial movement of the fireplace itself (and probably the chimney too) - this is an unsafe fireplace that should not be used.

But not using the fireplace is not enough to be sure this home doesn't have another fire or glue gas hazard.

If a fireplace and chimney have settled and thus have become unsafe, we need to determine right away if any other building appliances such as a boiler, furnace, water heater, or woodstove are using other flues in the same chimney.

If the chimney has multiple users it is unsafe for all of them.

Watch out:At PYROLYSIS EXPLAINED we document a Phil Hansey fireplace design that set the author's house afire on New Years' Eve in 1969. Gaps in the fireplace exposed wood to heat from the fire, eventually setting the house wall on fire. Dan Martin passed me a fire extinguisher as he asked "Is your wall supposed to glow like that?"

at FIREPLACE HEARTH DIMENSIONS & SUPPORT we illustrate adding support below a sagging fireplace hearth.

Watch out: in addition to cracks and gaps that mean heat and sparks can set a building on fire, cracks and gaps in masonry chimneys and fireplaces could presage a dangerous chimney collapse.

See these articles on chimney collapse hazards:

Fireplace Fire Hazards: Carpeting too Close to Fireplace

Carpets and other combustibles need to be kept away from the fireplace front and hearth.

Carpet at fireplace (C) Daniel Friedman

Often where the hearth sits at floor level we find that someone has installed carpeting right up to the fireplace - a fire hazard as our client is remarking in our photo (above).More unsafe hearths and inadequate clearance from fireplaces or wood or coal stoves are shown at FIRE CLEARANCES, WOOD COAL & PELLET STOVES.


Continue reading at FIREPLACE INSERTS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


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Fireplace & Woodstove Articles

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Publisher - Daniel Friedman