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CHIMNEY INSPECTION DIAGNOSIS REPAIR
BACKDRAFTING HEATING EQUIPMENT
CARBON MONOXIDE - CO
CHIMNEY CAP & CROWN
CHIMNEY CLEANING PROCEDURES
CHIMNEY COMPONENT DEFINITIONS
CHIMNEY CRACK DETECTION & DIAGNOSIS
CHIMNEY DRAFT & PERFORMANCE
CHIMNEY FIRE ACTION / PREVENTION
CHIMNEY HEIGHT & CLEARANCE CODE
CHIMNEY INSPECTION, FLUE INTERIOR
CHIMNEY LEANING, SEPARATION, MOVEMENT
CHIMNEY REPAIR METHODS
CHIMNEY STAINS & LEAKS
CHIMNEY TYPES & MATERIALS
DIRECT VENTS / SIDE WALL VENTS
DRAFT HOOD, GAS HEATER
DRAFT REGULATOR, DAMPER, BOOSTER
FIRE CLEARANCES INDOORS
FIREPLACES & HEARTHS
FLUE VENT CONNECTORS
MASONRY CHIMNEY GUIDE
METAL CHIMNEYS & FLUES
SAFETY RECALLS CHIMNEYS VENTS HEATERS
SOOT AT CHIMNEY TOP
STAIN DIAGNOSIS on BUILDING EXTERIORS
WOOD, COAL STOVES & FIREPLACES
This article describes chimney inspection procedures and critical chimney defects which can be observed from outdoors at ground level. We begin with the detection of chimney movement, its causes, its symptoms.
These articles continue with other chimney defects that can be found by visual inspection from outdoors at ground level, then from an on-roof inspection, followed by indoor inspections and ending with chimney-flue interior inspections.
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Here is a list of some (not all) common chimney defects visible from a more distant view, perhaps at ground level. Later we detail chimney defects that can best be observed from roof-level access.
[Click to enlarge any image]
We describe these and other chimney defects in detail in the following sections of this article.
A chimney which has settled and moved away from the building is almost certainly a serious safety hazard risking fire and flue gas leaks into the structure, and it is likely to require costly repairs or complete reconstruction. Details of how to see and evaluate chimney movement and separation are provided here.
A summary of the chimney footing problem is just below.
What happens if a chimney footing is missing or inadequate? Masonry chimneys represent a heavy concentrated load on the soil or support structure. Therefore, proper footing support is critical and is generally separated from the building footings except possibly at the exterior wall.
Some masonry chimneys are constructed with an inadequate footing, or no supporting footing whatsoever. Future settlement, movement, tipping, or separation of the chimney from the building is certainly likely in such installations.Even a casual inspection from outside would raise the question about the absence of a footing for the chimney shown in our photo. You will notice the erosion of soil from below a little concrete skirt around the chimney base of this concrete block chimney.
Homes built upon dry-laid stone foundations may have a chimney installed with its base sitting atop the foundation wall itself. Those chimneys might be stable, but be sure to review our warnings about dead end flues that are usually in use where such chimneys were built with no extension very far below ground level.
We continue below with an explanation of the causes of chimney movement, followed by a demonstration of how we spot evidence that chimney movement has been ongoing. Other articles in this series outline most other chimney defects that can be found outdoors or indoors on buildings.
At CHIMNEY MOVEMENT CAUSES we explain the common causes of chimney cracking, separation, leaning, tipping, or collapse.
At CHIMNEY MOVEMENT, ONGOING vs STATIC we continue this article with a case reporting evidence of ongoing chimney movement, repeated repairs, and the need to remove and rebuild a large masonry chimney.
Other Chimney Defects Visible by Outdoor Ground-Level Inspection
Overgrown chimneys & flues - trim back vegetation
Watch out: As you can certainly see from our photos above, tree, shrubbery or vine growth close to or covering a chimney can be a serious or even fatal hazard including risk of
Bird or other animal nests in or on chimneys - fire & gas hazards
As you can certainly see from our photo (left), this chimney, located in Rabat, Morocco, serves as a home for a stork's nest. This chimney top is essentially totally blocked by highly-combustible material - a bird's nest.
Watch out: even in areas where storks are not common, other smaller birds, squirrels, and some other animals may make a smaller nest inside the chimney or its flue, presenting hazards of blocked flue, fire, and potentially fatal carbon monoxide poisoning.
Risk of Hidden Chimney Damage - hybrid structures
This next chimney shown at below left ... well we're not sure what the heck we've got here.
We see a fired clay masonry flue tile projecting through a flat, leaky, too small, metal chimney cap surrounded by a wood and plywood structure.
We suspected that this was a masonry chimney that had suffered frost damage.
We've got a few concerns:
See CHIMNEY CAP & CROWN for definitions of chimney rain cap, chimney cap, chimney crown, and for more examples of chimney top defects that may be visible from the ground or from an on-roof inspection.
Poorly-secured or poorly-supported factory-built chimneys risk collapse
More about this chimney is found at BRACING for METAL CHIMNEYS.
After reviewing this "ground level chimney inspection guide" readers should then review CHIMNEY INSPECTION at ROOFTOP which describes chimney defects which may be difficult or impossible to detect from a ground-level inspection.
Readers interested in the outdoor portion of chimney inspections should review FOUNDATION SUPPORT for CHIMNEYS (below in this article) followed by the next article: CHIMNEY LEANING, SEPARATION, MOVEMENT and also CHIMNEY COLLAPSE Risks, Repairs.
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