Buying a home with a basement

When a listing says a basement is stubbed (or "stubbed for a bath"), the builder ran drain and vent pipes into the basement and capped them, usually short white PVC pipes coming up through the concrete floor or out of the wall. It means a future bathroom can be added without breaking up the slab to run drains.

It's a real head start, but it isn't a bathroom yet. Water supply lines, a vent, electrical, framing, an exhaust fan, fixtures and finishes still have to be added, along with a permit and inspections.

If the basement floor sits below the sewer or septic line, the drains can't flow out by gravity. The bathroom will need a sewage ejector pump in a sealed basin to lift the waste up and out. It works well, but it adds cost, needs power, and should have an alarm.

Appraisers follow a national measuring standard that counts space that's partly or fully below ground separately from the main living area, even when it's beautifully finished. That's true for a walk-out basement too, as long as any part of it is below grade.

So a home listed with "3,000 square feet" may be 2,000 above grade plus a 1,000-square-foot finished basement. A finished basement still adds value, just usually less per square foot than the floors above it. Compare homes above grade to above grade, and basement to basement.

Signs of past water

• White, chalky powder on concrete walls or floors (efflorescence): minerals left behind when water seeps through.
• Stains or tide lines on walls, the bottom of drywall, or stored boxes.
• A musty smell, mold or mildew, or a dehumidifier running hard.
• Rust on the legs of the water heater, furnace or shelving.
• Fresh paint or waterproofing paint on just the lower walls.
• Warped baseboards, lifting flooring, or new carpet in only one corner.
• A sump pump, interior drain channel or covered pit. Not a bad sign on its own, but ask why it's there and whether it runs.

Where it comes from, and the fixes

Start outside. Most basement water comes from gutters that overflow, downspouts that dump next to the house, or soil that slopes toward the foundation. Extending downspouts several feet out and regrading are the cheapest fixes and often solve it.

Interior drainage. A drain channel around the inside edge of the floor carries water to a sump pump that sends it outside. A battery backup keeps it running in a storm power outage.

Exterior waterproofing. Digging down outside, sealing the wall and adding drain pipe at the footing. The most thorough fix and the most expensive.

Humidity. Even a dry basement can be damp in a Georgia summer. A dehumidifier keeping it around 50% helps prevent mold and musty smells.

Radon is a natural radioactive gas from the soil, and Northeast Georgia has plenty of it. Because a basement is surrounded by soil, it's usually where radon levels are highest. A test is placed in the lowest level you'd use as living space, so in a home with a basement, that's typically the basement.

A sump pit or floor drain can be an easy path for radon into the house. Mitigation systems often seal the sump lid and pull gas from under the slab and out above the roof. A high reading is common and very fixable, and we'll negotiate it with the seller during due diligence.

If you finish a basement after you move in, retest. Spending more time down there and changing the HVAC can change your exposure.

Basement walls are usually poured concrete or concrete block. Almost every concrete basement has some small cracks from curing and settling. Your home inspector will look at them, and most are minor. These deserve a closer look:

• Horizontal cracks or walls that bow or lean inward, a sign of soil pressure from outside.
• Stair-step cracks along the mortar joints of a block wall.
• Cracks wider than about 1/4 inch, or wider at one end than the other.
• Cracks that leak, or that have been patched more than once.
• Doors upstairs that stick, or a floor that slopes noticeably.

Finishing a basement needs a building permit in most of our counties, with inspections for framing, electrical, plumbing and HVAC. Plenty of finished basements were done without one. That can matter later: problems hidden behind drywall, trouble with insurance claims, and questions when you sell.

If you're buying a home with a finished basement, ask whether it was permitted. Your agent or the county building department can often look up permit records by address.