What we verified in “Foundation cracks: what to check and who to call”

Statements and where we checked them

The statements with rules, figures or dates, with the exact place in the source and the date we checked them.

1. According to the EPA, radon is a radioactive gas that comes from the natural decay of uranium found in nearly all soils; it typically moves up through the ground and into your home through cracks and other holes in the foundation; it gets in through cracks in solid floors, construction joints, cracks in walls, gaps in suspended floors and gaps around service pipes; and any home may have a radon problem, new or old, with or without a basement.

   Sources 1 · EPA, A Citizen’s Guide to Radon, 'How does radon get into your home?': 'It comes from the natural decay of uranium that is found in nearly all soils. It typically moves up through the ground to the air above and into your home through cracks and other holes in the foundation'; 'Any home may have a radon problem'; 'Cracks in solid floors'; 'Construction joints'; 'Cracks in walls'; 'Gaps in suspended floors'; 'Gaps around service pipes' · Checked November 6, 2026

2. According to the EPA, test your home for radon, which is easy and inexpensive; there are low-cost do-it-yourself test kits you can get by mail and in some hardware stores; for a list of qualified testers, contact your state radon office; short-term tests stay in the home from two to 90 days; and the EPA recommends fixing your home if the radon level is 4 picocuries per liter (pCi/L) or higher.

   Sources 1 · EPA, A Citizen’s Guide to Radon: 'Test your home for radon—it’s easy and inexpensive'; 'Fix your home if your radon level is 4 picocuries per liter (pCi/L) or higher'; 'low-cost “do it yourself” radon test kits you can get through the mail and in some hardware stores'; 'contact your state radon office about obtaining a list of qualified testers'; 'Short-term tests remain in your home for two days to 90 days' · Checked November 6, 2026

3. According to the EPA, you can't see or smell radon, testing is the only way to know your level of exposure, and all homes should be tested.

   Sources 2 · EPA, Radon: 'You can’t see or smell radon. Testing is the only way to know your level of exposure'; 'All homes should be tested for radon.' · Checked November 6, 2026

4. According to the EPA, because radon levels vary from day to day and season to season, a short-term test is less likely than a long-term test to show your year-round average; if you need results quickly, a short-term test followed by a second short-term test may be used to decide whether to fix your home.

   Sources 1 · EPA, A Citizen’s Guide to Radon: 'Because radon levels tend to vary from day to day and season to season, a short-term test is less likely than a long-term test to tell you your year-round average radon level. If you need results quickly, however, a short-term test followed by a second short-term test may be used to decide whether to fix your home' · Checked November 6, 2026

5. According to the EPA, absorbent materials such as ceiling tiles and carpet may have to be thrown away if they become moldy; if the moldy area is less than about 10 square feet, in most cases you can handle the job yourself following its guidelines; and don't paint or caulk moldy surfaces: clean and dry them first.

   Sources 3 · EPA, A Brief Guide to Mold, Moisture and Your Home: 'Absorbent or porous materials, such as ceiling tiles and carpet, may have to be thrown away if they become moldy'; 'If the moldy area is less than about 10 square feet (less than roughly a 3 ft. by 3 ft. patch), in most cases, you can handle the job yourself, follow the guidelines'; 'Do not paint or caulk moldy surfaces. Clean up the mold and dry the surfaces before painting.' · Checked November 6, 2026

6. According to the EPA, the method mainly used to reduce radon is a vent pipe system and fan that pulls radon from beneath the house and vents it outside; it does not require major changes to the home; and sealing foundation cracks and other openings makes this kind of system more effective and cost-efficient.

   Sources 1 · EPA, A Citizen’s Guide to Radon: 'the one primarily used is a vent pipe system and fan, which pulls radon from beneath the house and vents it to the outside'; 'does not require major changes to your home'; 'Sealing foundation cracks and other openings makes this kind of system more effective and cost-efficient' · Checked November 6, 2026

7. According to the EPA, make sure the ground slopes away from the building foundation, so water does not enter or collect around it; fix leaks and other water problems as soon as possible; and if wet materials are dried within 24 to 48 hours, in most cases mold will not grow.

   Sources 3 · EPA, A Brief Guide to Mold, Moisture and Your Home: 'Make sure the ground slopes away from the building foundation, so that water does not enter or collect around the foundation'; 'Fix plumbing leaks and other water problems as soon as possible'; 'If wet or damp materials or areas are dried 24-48 hours after a leak or spill happens, in most cases mold will not grow' · Checked November 6, 2026

8. According to the U.S. Geological Survey (USGS), sinkholes are common where the rock below the surface is limestone, carbonate rock, salt beds or other rocks that groundwater can dissolve; the land can stay intact for a while until the underground spaces get too big and the surface collapses suddenly; and the most damage tends to occur in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee and Pennsylvania.

   Sources 4 · USGS, Sinkholes: 'Sinkholes are common where the rock below the land surface is limestone, carbonate rock, salt beds, or other rocks that can naturally be dissolved by groundwater'; 'the land usually stays intact for a while until the underground spaces just get too big'; 'a sudden collapse of the land surface can occur'; 'The most damage from sinkholes tends to occur in Florida, Texas, Alabama, Missouri, Kentucky, Tennessee, and Pennsylvania.' · Checked November 6, 2026

9. In Florida, section 627.706 of the Statutes says every property insurer must cover catastrophic ground cover collapse; it must make available, for an additional premium, coverage for sinkhole losses; it may require an inspection before issuing that coverage; and the policy may carry a sinkhole deductible of 1, 2, 5 or 10 percent of the dwelling limits.

   Sources 5 · Fla. Stat. §627.706(1)(a): 'Every insurer authorized to transact property insurance in this state must provide coverage for a catastrophic ground cover collapse'; (1)(b): 'The insurer shall make available, for an appropriate additional premium, coverage for sinkhole losses'; 'The insurer may require an inspection of the property before issuance of sinkhole loss coverage'; 'a deductible amount applicable to sinkhole losses equal to 1 percent, 2 percent, 5 percent, or 10 percent of the policy dwelling limits' · Checked November 6, 2026

10. In California, the California Residential Mitigation Program's Earthquake Brace + Bolt (EBB) offers up to $3,000 for homeowners to seismically retrofit their houses, and income-eligible homeowners can apply for an additional grant of up to $7,000; the retrofit bolts the foundation to the frame of the house and, where there are cripple walls in the crawl space, braces them with plywood, to help keep the house from sliding or toppling off its foundation in an earthquake; it is only done on wood-framed, pre-1980 homes with a raised foundation; and registration is open for a limited time each year.

    Sources 6 · CRMP, EBB Retrofit: 'Earthquake Brace + Bolt offers up to $3,000 for homeowners to seismically retrofit their houses'; 'Income eligible homeowners can also apply for an additional grant of up to $7,000'; 'the foundation is "bolted" to the frame of the house, and when there are walls called "cripple walls" in the crawl space under the house, they are "braced" with plywood'; 'This helps prevent the house from sliding or toppling off of its foundation during an earthquake'; 'An EBB seismic retrofit is only done on wood-framed, pre-1980 homes with a raised foundation'; 'EBB program registration is open for a limited time each year' · Checked November 6, 2026

11. According to the FTC, consider only licensed and insured contractors and confirm the license with your state or county government; get multiple estimates; a written estimate should include a description of the work, the materials, the completion date and the price; don't automatically choose the lowest bidder; and ask for an explanation if there's a big difference among them.

    Sources 7 · FTC, How To Avoid a Home Improvement Scam: 'Consider only contractors who are licensed and insured. Check with your state or county government to confirm a contractor’s license'; 'Get multiple estimates. A written estimate should include a description of the work to be done, materials, completion date, and the price. Don’t automatically choose the lowest bidder. And ask for an explanation if there’s a big difference among the estimates.' · Checked November 6, 2026

12. According to the FTC, scammers knock on your door looking for business because they are 'in the area', pressure you for an immediate decision, ask you to pay for everything up front or only accept cash, and suggest you borrow from a lender they know.

    Sources 7 · FTC, How To Avoid a Home Improvement Scam: 'Scammers knock on your door looking for business because they are “in the area.”'; 'Scammers pressure you for an immediate decision'; 'Scammers ask you to pay for everything up front or only accept cash'; 'Scammers suggest you borrow money from a lender they know' · Checked November 6, 2026