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.

Masonry Fireplace Specifications, Safety Hazards, Recommendations

The burned wood floor in front of the fireplace shown here is a sweet example of why building codes and fire experts require a masonry hearth of adequate dimensions at the front of a fireplace.

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 accumulated creosote in the fireplace chimney flue.

[Click to enlarge any image]

See CHIMNEY FIRE ACTION / PREVENTION

Fireplace Damage and Unsafe Hearths due to Chimney or Fireplace Settlement

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 This drawing is obsolete in that it is missing a combustion air supply for the fireplace.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.

[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

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.

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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

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:

• CHIMNEY COLLAPSE RISKS, REPAIRS
• BRICK CHIMNEY CRACKS & COLLAPSE - case of an imminent catastrophic chimney collapse

Fireplace Fire Hazards: Carpeting too Close to Fireplace

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

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.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2021-04-11 by (mod) - repair priorities for a damaged masonry fireplace

@Catherine Sherlock, I'll be glad to try to help, but need to know what you want or what question you have.

Watch out: From clicking to enlarge your photo I see many burns on a wood or parquet floor that looks in poor condition; there could be a fire hazard; certainly you should not use the fireplace before both fireplace and the entire chimney and flue are inspected for safety. A professional, certified chimney sweep ought to be able to give you that information.

On 2021-04-11 by Catherine Sherlock

My fireplace is damaged

On 2020-11-22 by (mod) - first priorities for fireplace safety

D

Watch out: before attempting any repair to the fireplace hearth

1. stop using the fireplace immediately and don't use it until it's inspected and repaired

2. have the chimney and flues inspected for safety, especially if the same chimney carries other flues such as for your home heating boiler, furnace, water heater - as movement in a hearth can stress, crack, damage other chimney components making the chimney unsafe, risking fire or carbon monoxide poisoning

3. be sure you have working CO and smoke detectors now.

It might be necessary to remove flooring and install masonry supported from below, but that said, there are other repair options and I would not specify one before understanding the type of fireplace and its materials and the damage already done.

I would not simply lay a marble or other after-market "hearth" onto an existing floor. The fire hazards include sparks that fall through a crack or gap onto combustibles and heat transmission combined with pyrolysis to risk a later ignition of the floor or surrounding structure.

Also take a look at

FIREPLACE HEARTH DIMENSIONS & SUPPORT

On 2020-11-22 by D

It appears our living room hearth was not built on a cement pad. The hearth is now pulling away from the fireplace---gap is about 3/4 inch now. This fireplace is on our first floor with another fire place directly below in the basement which was built correctly.. How can fix the one not built on a cement pad? Should we just tear it out?

On 2020-11-19 by Anonymous

House is 2 feet off ground, same with fire place floor. Not sure what held up concrete floor

On 2020-08-11 by Andrew

had a 5kw wood burner stove fitted 3 years ago. Have now noticed some major cracking of the plaster surround and also movement in the hearth. The plaster also feels slightly damp to touch.

On 2020-08-02 - by (mod) -

Danny

What are the hearth materials, and how is the hearth supported. You may be able to use a concrete repair epoxy if it's masonry AND if the hearth is supported safely and adequately.

On 2020-08-02 by danny hawks

corner of fireplace hearth broke off. how can i repair?

Question: fireplace "avalanched" into the living room

The front of my son's fireplace avalanched into his living room. The exterior of the chimney looks great.

We're waiting for engineer's report and how much of this insurance will cover. We suspect they will cover only the portion that has - abruptly- collapsed.

The contractor does not want to repair only the interior and then take responsibility for the entire chimney. He thinks it is safest to replace the entire chimney/fireplace.

Now we're looking for a second contractor to get a second opinion. What an expensive mess. Any advice is appreciated. - Barbara Holub 2020/02/07

Reply:

Barbara:

I'm not sure that the entire chimney needs to be replaced but I can absolutely agree that if I were the contractor called to this job,

• one look at the sloppy masonry exposed in your photo,
• the apparent lack of a lintel across the fireplace opening,
• the apparent absence of proper masonry ties securing the veneer of the fireplace to the block chimney structure,
• the cockeyed blockwork,
• and perhaps other details that can be observed on-site

all point to an amateur chimney mason whose work is at least questionable.

As a contractor I'd not be willing to accept responsibility for work that I did not perform myself and that worse, is mostly not visible.

1. What are the country and city of the home, when was it built, and who built this chimney and fireplace?
2. Outside are there signs of chimney movement, leaning, cracking, settlement, footing defects?
3. In the chimney has the flue been inspected for integrity, damage, sealing, alignment, materials, by a certified chimney sweep?
4. Has anyone run a chimscan camera through the flue?
5. Is there a basement or crawl space that might give clues to the chimney footing depth?
6. Are there photos from time of construction of the chimney?

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Continue reading at FIREPLACE HEARTH DIMENSIONS & SUPPORT or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see FIREPLACE & HEARTH DAMAGE FAQs - questions & answers posted originally at this page

Or see these

Recommended Articles

• CHIMNEY COLLAPSE RISKS, REPAIRS
• CHIMNEY CLEANING PROCEDURE
• CHIMNEY CLEANOUT DOORS
• CHIMNEY FIRE ACTION / PREVENTION
• CHIMNEY FLUE INSPECTION CAMERA
• CHIMNEY DRAFT & PERFORMANCE
• COMBUSTION AIR DEFECTS
• FIREPLACES & HEARTHS - home
• CREOSOTE DEPOSITS, FIRE HAZARD
• FIREPLACE DAMAGE & UNSAFE HEARTHS
• FIREPLACE DAMPER DEFECTS, REPAIRS
• FIREPLACE FLUE SIZE SPECIFICATIONS
• FIREPLACE HEARTH DIMENSIONS & SUPPORT
• FIREPLACE INSERTS INSTALL, INSPECT, REPAIR
• FIREPLACE INSPECTIONS
• FIREPLACE INSPECTION PRE-FAB
• GAS FIREPLACES & GAS LOGS - home
• GAS FIREPLACE VENT CLEARANCE REQUIREMENTS
• GAS FIREPLACE CERAMIC STAINS
• INACCESSIBLE CONNECTIONS FIREPLACE, WOODSTOVE
• RUMFORD FIREPLACE DESIGN RULES
• PYROLYSIS EXPLAINED

Suggested citation for this web page

FIREPLACE DAMAGE & UNSAFE HEARTHS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to CHIMNEYS & FLUES

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Citations & References

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