Sloping or uneven floor

Symptoms

• Floor visibly slopes toward one side of a room
• A ball or round object rolls on its own toward one spot
• Doors and windows nearby stick or don't close properly
• Cracks in nearby walls or ceiling

Likely causes

• CommonNormal settling of an older home's foundationMost homes settle somewhat over decades, and minor slopes are common and often not urgent.
• PossibleUndersized or sagging floor joistsJoists that are too small for their span or have sagged over time can create a dip.
• PossibleFoundation issue (settling, heaving, or a failing support post)More significant slopes, especially ones that are new or worsening, can point to a foundation problem.
• PossibleWater damage or rot weakening structural supportLong-term moisture exposure can rot support posts or beams, causing gradual sagging.

What to do

1. Use a marble or level to identify the direction and rough severity of the slope.
2. Check nearby doors and windows for new sticking or gaps, which can indicate the slope is recent or worsening rather than old and stable.
3. Inspect the basement or crawlspace below, if accessible, for visible sagging beams, cracked support posts, or water damage.
4. Look at exterior grading and drainage around the foundation, since water pooling near the foundation can contribute to settling over time.
5. Photograph any cracks in walls, ceilings, or the foundation and note whether they seem to be widening over time.
6. For minor, long-standing, stable slopes in an older home, this is often more of a character quirk than a hazard, though it's still worth a professional opinion if you're unsure.
7. For a new or worsening slope, have a structural engineer or foundation specialist assess it before doing any surface-level flooring work.

Tools and parts

• Marble or level
• Flashlight

When to call a pro

Call a structural engineer or foundation repair specialist for any new, worsening, or significant floor slope, since the underlying cause needs proper diagnosis.

Safety