Construction · Lesson 11 of 13Beginner4 min read

Troubleshooting a House by Symptom

Houses tell you when something is wrong: a crack, a stain, a door that sticks, a musty smell. Use the finder to narrow down the cause, learn what you can safely check, and know when it’s time for a licensed pro or an engineer.

How to think it through

Follow the water. Many house problems involve water somewhere. Work from the outside in: roof, gutters, grading, siding, windows, then the inside.
Notice the timing. Only after rain? Only in winter? Only in humid weather? The timing often points straight at the cause.
Watch for change. Mark both ends of a crack with a pencil line and the date, and take a photo. A crack that stays the same is very different from one that grows.
Look, don’t open. Check what you can see safely from the ground, from inside, or from the attic or basement. Leave roofs, structure, and anything that might contain lead paint or asbestos alone until you know more.

Pick a symptom, then answer one question. The advice is general; a pro who can see the house comes first.

The finder at a glance: first checks, and who to call
Symptom	Check first	Call
Thin foundation crack that isn’t changing	Mark and date the ends; keep roof water away from the wall.	A foundation contractor if it leaks; an engineer if it grows.
Crack that grows, shifts or bows	Photograph and measure it; don’t brace or repair it yourself.	A structural engineer.
Water in the basement after rain	Gutters, downspout extensions, grading, window wells, sump pump.	A drainage or waterproofing contractor.
Damp basement walls in humid summer weather	Condensation: keep humid air out, check the dryer vent.	Usually no one; an energy auditor if it persists.
Ceiling stain during rain	From the ground and the attic: flashing, shingles, wet wood.	A roofer.
Ice dams	Attic air leaks and thin insulation at the eaves.	A weatherization or insulation contractor; a roofer for leaks.
Sagging floor	From below: cut, cracked or rotted joists, missing posts.	A structural engineer.
Mold over about 10 square feet	The water source.	A contractor experienced with mold.
Drafts	Incense-stick test; caulk and weatherstripping.	An energy auditor.
Peeling outside paint	Gutters, flashing, caulk; assume lead before 1978.	An EPA-certified renovator for pre-1978 paint.

Cracks: which are common and which aren’t

Concrete shrinks a little as it dries, and that shrinking pulls on it from inside. University of Minnesota Extension says concrete and concrete-block foundations usually develop some cracks, and that drainage usually removes the water from them, though repair may be needed. A thin crack that stays the same size is common.

Drywall moves too. Wood framing shrinks as it dries and swells and shrinks a little with the seasons, so small cracks at corners and joints and the occasional nail pop are common in houses, and they’re easy to patch.

Other signs call for a professional: a crack that keeps getting wider or longer, one side of a crack that has moved out of line with the other, a foundation wall that bows or leans, floors that sag more over time, or doors and windows that suddenly start to bind. Have a structural engineer or an experienced foundation contractor look. Repairs to structure need a permit.

StopWhen water is pouring in

If water is coming from a broken pipe, shut off the main water valve (Being an Adult 101 shows how) and call a plumber. Then dry everything you can within 24 to 48 hours, as EPA advises, to head off mold.

Check yourself

Tap an answer to check it, or open “Show the answer.”

According to EPA, homeowners can often clean up mold themselves if the area is less than about…
Show the answer
10 square feet. Less than about 10 square feet. Larger jobs, or mold after heavy water damage, call for professional guidance.
Your foundation has a thin crack that hasn’t changed in a year. What does University of Minnesota Extension say about cracks like this?
Show the answer
Concrete and block foundations usually develop some cracks. Some cracking is common. Watch for change, and keep water away.
A crack keeps growing, and nearby doors have started to stick. What should you do?
Show the answer
Have a structural engineer or experienced foundation contractor look. Growing cracks with sticking doors can mean movement; get it evaluated.

Go deeper

U.S. EPA: A Brief Guide to Mold, Moisture and Your Home EPA’s mold and moisture guide.
University of Minnesota Extension: Moisture in Basements: Causes and Solutions University of Minnesota Extension on wet basements.
University of Minnesota Extension: Dealing with and Preventing Ice Dams University of Minnesota Extension on ice dams.
U.S. Department of Energy: Consumer Guide to Air Sealing the Home DOE’s guide to finding and sealing air leaks.
Being an Adult 101: Shut Off Your Home’s Water Shut off your home’s water.

Sources

The finder also draws on these sources:

I finished this lessonSaved on this device only.

A free course from Teddy Rook Book. It explains how houses are built in general and follows U.S. sources; the local building code, the building department and the manufacturer’s instructions are the final word.