⌂HouseSymptomsHOUSE INTELLIGENCE

12 complete symptom paths42 guides and 60 questions in each 1,460 Grade A articlesOne searchable, connected knowledge library 140 official sourcesEvidence context with explicit limits

Failure Fingerprints

Learn the pattern behind the symptom.

Each fingerprint condenses where a failure appears, when it changes, what it usually looks like and the check that best separates it from similar causes.

31canonical failure fingerprintsOpen side-by-side comparisons →

↟Cold periods, especially with high indoor humidity

Air leakage into the attic

Broad frost or staining on cold roof sheathing

Best separatorTrace ceiling air paths and compare frost concentration

↑Wet seasons, saturated soil or persistent ground moisture

Capillary moisture rise

Low damp band, salts and coating failure

Best separatorMap moisture height and inspect exterior drainage and ground cover

❄Cold weather

Cold bridge at framing

Linear or edge condensation and dark surface marks

Best separatorCompare surface temperatures across adjacent materials

△Progressive or following ground and drainage changes

Differential settlement

Diagonal or stepped cracks, sticking openings and level change

Best separatorMeasure change over time and assess drainage and structure

↝After showers and during cold weather

Disconnected bathroom exhaust

Localized frost, wet insulation or staining around duct termination

Best separatorVerify the duct is continuous and terminates outdoors

☂Rain, strongest during high roof runoff

Downspout discharge too close

Localized saturated soil and nearby basement entry

Best separatorWatch discharge path during rain and extend it safely away

⇧When another fixture drains or a toilet flushes

Drain vent obstruction

Gurgling, trap movement and possible sewer odor

Best separatorObserve fixture interaction and have vent route assessed

╱Seasonal or after normal framing movement

Drywall joint movement

Fine crack following a straight joint or corner

Best separatorTrack width and confirm it is confined to finish layers

✧After moisture passes through masonry and evaporates

Efflorescence

Dry white crystalline powder that can return after cleaning

Best separatorConfirm crystalline texture and trace moisture source

⌁Rain, especially wind-driven

Failed exterior sealant

Localized entry beside cracked or separated joint

Best separatorInspect joint continuity without assuming sealant is the only defense

▦Can vary with temperature but cannot be wiped away

Failed insulated-glass seal

Fog, haze or mineral residue trapped between panes

Best separatorTry cleaning both exposed surfaces and compare adjacent units

◉Flushing or movement of fixture

Failed toilet seal

Soft floor, odor, staining or hidden wetting around base

Best separatorInspect connection and floor condition after controlled use

☂Wind-driven or prolonged rain

Failed window flashing

Water at top or lower corners and staining below opening

Best separatorCorrelate wind direction and inspect water-management layers

╱Rain, thaw or saturated soil

Foundation crack water entry

Water, staining or salts following a visible crack

Best separatorDocument entry during weather and inspect exterior drainage

↘Heavy rain and snowmelt

Ground slopes toward foundation

Repeated perimeter water loading and low-wall dampness

Best separatorObserve runoff and levels during rain

≈Fixture use or continuous pressurized leakage

Hidden plumbing leak

Localized active dampness, staining or soft finish

Best separatorCompare the symptom before and after controlled fixture use

%Overnight, cooking, bathing or limited ventilation

High indoor humidity

Widespread condensation rather than one local wet spot

Best separatorLog relative humidity and compare ventilation conditions

▤Cold or hot weather

Insulation void or compression

Localized thermal stripe without obvious air movement

Best separatorCompare surface temperature across neighboring bays

↝Windy or cold weather

Interior air leakage

Moving draft and localized cold discomfort

Best separatorUse smoke-free airflow indicators or temperature comparison

⚡Load, plug movement or continuously

Loose electrical connection

Buzzing, heat, odor, discoloration or intermittent power

Best separatorStop using the circuit and have it tested by a qualified electrician

⚠Under heavy load

Overloaded electrical circuit

Breaker operation, warmth or voltage drop

Best separatorReduce load and have circuit capacity assessed

↳During high flow or after repeated use

Partial drain blockage

Slow drainage, gurgling and water-level changes

Best separatorCompare flow and reactions across connected fixtures

↔As heating warms or cools

Pipe thermal expansion

Light repeated ticks, rubbing or creaks

Best separatorCorrelate exact sound timing with temperature change

!Immediately when a valve or appliance closes

Rapid valve closure

One or more sharp impacts

Best separatorIdentify the exact fixture that triggers the bang

☂Rain, wind-driven rain or thaw

Roof water entry

Localized rings, wet insulation or a path below a penetration

Best separatorCorrelate moisture with weather and inspect above the mark

▧After shower or bath use

Shower waterproofing defect

Localized wetting, loose finishes or staining below

Best separatorMap use correlation and inspect the full waterproofing assembly

◐Builds gradually during heating seasons or combustion exposure

Soot deposition on a cold surface

Dry gray-black smudging that follows airflow or thermal patterns

Best separatorCompare wipe texture, moisture history and distribution across cold lines

◌Cold weather, showering, cooking or overnight occupancy

Surface condensation

Diffuse droplets, wet edges or recurring surface spotting

Best separatorRecord surface temperature and indoor humidity together

✣After repeated high humidity or persistent surface dampness

Surface microbial growth

Speckled, patchy or soft growth that follows moisture-prone areas

Best separatorCheck texture, recurring moisture and whether the surface remains damp

❄Most evident during strong indoor-outdoor temperature differences

Thermal bridge

Stable cold stripe or geometric surface-temperature pattern without air movement

Best separatorCompare surface temperature across neighboring construction while checking for draft

♢After chronic wetting rather than one short event

Wood decay

Softness, darkening, loss of section and musty odor

Best separatorProbe only where safe and identify the moisture source first