Measure your floor slope yourself
You don't need a Zip Level to know if your floor is sloping. A 4-foot level and a tape measure will get you 80% of the way there.
What you'll learn
- Why a marble test is fast but imprecise
- How to use a 4-foot level + tape measure to quantify slope
- What slope ranges matter (1 in. over 20 ft = noticeable, 2 in. = call us)
- How to map slope across multiple rooms to see the pattern
- What "differential" slope means and why it matters more than absolute slope
Step by step
- Get a 4-foot bubble level and a tape measure.
- Lay the level on the floor, one end raised slightly until the bubble centers.
- Measure the gap under the raised end. That's your slope over 4 feet.
- Multiply by 5 to estimate slope per 20 feet (rough rule).
- Repeat in 4-6 locations across the house and map the readings.
Safety note
Anything over 1 inch slope per 20 feet is worth a professional level survey.
Rather have a pro handle it?
Call and we connect you with a local foundation pro in San Diego County.
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