How can I check if a floor is sloping out of level?

Monday, October 1, 2018

Three Ways To Check If A Floor Is Level

Sometimes a floor feels like it’s sloping as you walk across it, but you’re just not sure. There are several ways to verify that a floor has settled out-of-level over time in either, or both, directions in a room:

1) Set a ball on the floor and see if it rolls, and in what direction. This is the cheapest and easiest method. A big steel ball bearing is best, but any sturdy, smooth-surface ball will do. This does not work well on carpeting or ceramic tile because the ball is stopped either by the texture of the carpet or the grout grooves between the ceramic tiles. But it is a simple, easy way to check any smooth floor surface such as wood, vinyl tile, sheet vinyl, and laminates. Set the ball at several locations in the room to get a good idea of which way it’s sloping. If there are sagging wood joists supporting the floor the room may even slope towards the middle. Bear in mind that most floors are not perfectly level and if the ball rolls a few inches in one direction or another before stopping it doesn’t really mean anything.

2) Lay a bubble level at several locations on the floor. A 2-foot or longer carpenter’s level is best, but a small “torpedo” level will do. Place the level at intervals along a straight line across the room to get a good reading. 

3) Buy a self-leveling laser level at a big-box home improvement store or online. You can get a decent one for under $50, and take measurements of the distance from the floor to the laser beam with a tape measure at multiple locations around the room in several directions. Measurements that are getting larger as you move away from the laser level means the floor is sloping downwards and, conversely, progressively smaller measurements mean it’s sloping uphill. You may want to make a simple diagram to plot your measurements.

   To learn more about the causes of sloping floors, go to our blog Why do the floors slope in this old house? 

• • • • • • • • • • • • • • • • • • • • • • • • • • • 

Here’s links to a collection of our other blog posts about STRUCTURE AND ROOMS:

What are the building code requirements for notching and boring holes in a wall stud? 

What causes dark or light "ghost" lines on ceilings and walls?

Can you access or exit a bedroom through another bedroom?

What is the difference between a carport and a garage? 

What are simple ways to find the cause of a ceiling stain?

What is the minimum size of habitable rooms in a house according to the building code? 

Why is my garage ceiling sagging? 

How can I identify what kind of wood flooring I am looking at?

Why does my concrete floor slab sweat and get slippery?

What is the minimum ceiling height for rooms in a house? 

Why are there score line grooves in the concrete floor of the garage?

How much can I cut out of a floor joist? 

What are the common problems when a homeowner converts a garage to conditioned living space, such as a family room?

• How can I tell if a wall is load-bearing? Which walls can I take out? 

   Visit our STRUCTURE AND ROOMS page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

How To Look At A House

McGarry and Madsen's home inspection blog for buyers of  

site-built, mobile/manfuactured and modular homes






Air Conditioner & Furnace Age/Size



Aging in Place


Click Below  

for Links

to Collections

of Blog Posts

by Subject


Doors and Windows


Energy Efficiency

Fireplaces and Chimneys

Heating and Air Conditioning

Home Inspection

Hurricane Resistance

Electrical Receptacle Outlets

Electrical Panels

Garages and Carports

Common Problems

Exterior Walls & Structures



Life Expectancy

Mobile/Manufactured Homes

Older and Historic Houses

Mold, Lead & Other Contaminants

Modular Homes

Metal Roofs



Pool and Spa

Roof and Attic




"Should I Buy A..."


Termites, Wood Rot & Pests

Structure and Rooms


Water Heaters

Water Heater Age

Septic Tank Systems

Plumbing Pipes


When It First Became Code

Park Model Homes

Shingle Roofs


Wind Mitigation Form

"Does A Home


"What Is The Difference Between..."


Concrete and Concrete Block


Rain Gutters


Crawl Spaces

Building Permits

Clay Soil




HUD-Code for Mobile Homes

Flat Roofs

Sprinkler Systems

4-Point Inspections

Frequently Asked Questions (FAQ)

Building Codes

Inspector Licensing

& Standards

Washers and Dryers



Electrical Wiring

Plumbing Drains and Traps

Smoke & CO Alarms

Top 5 results given instantly.

Click on magnifying glass

for all search results.