How to Fix Uneven Floors in an Old House: A Comprehensive Guide

How to Fix Uneven Floors in an Old House
Images / Bay Area Underpinning

Uneven floors can be a significant problem in any home, but they are particularly prevalent in older houses.

If you’re dealing with this issue in your own home, it’s essential to understand the different types of flooring problems and how to address them effectively.

In this comprehensive guide, we’ll explore how to fix uneven floors in an old house, covering key topics such as the causes of uneven floors, the differences between slanting/sloping and sagging floors, various repair methods, and safety considerations.

Introduction to Uneven Floors in Old Houses

Uneven floors can cause a range of problems, from minor annoyances to serious safety hazards.

They can also be an indication of underlying structural issues, which may require professional attention.

In this section, we’ll discuss some of the common causes of uneven floors in old houses and introduce the main types of flooring problems you might encounter.

Common Causes of Uneven Floors

Old houses are particularly susceptible to uneven floors due to a variety of factors, including:

  1. Settling foundations: Over time, the ground beneath a house can settle unevenly, causing the foundation to shift and leading to uneven floors.
  2. Deteriorating wooden supports: Wooden beams and joists can rot or become damaged due to moisture, termites, or other factors, causing sagging or uneven floors.
  3. Poor construction: In some cases, uneven floors may be the result of poor construction techniques or materials, particularly in older homes built before modern building codes were in place.

Types of Flooring Problems: Slanting/Sloping vs. Sagging Floors

Not all uneven floors are the same, and it’s important to understand the differences between the two main categories of flooring problems: slanting/sloping floors and sagging floors.

  • Slanting/Sloping Floors: These are floors that have a general, overall slant, often caused by foundation issues. For example, a floor might slope down 1 or 2 inches over the course of 15 to 20 horizontal feet.
  • Sagging Floors: These floors may be generally level from end to end but have sags or dips in certain places, often caused by issues with the wooden supports beneath the floor.

How to Diagnose the Cause of Uneven Floors

How to Fix Uneven Floors in an Old House
Images / Bay Area Underpinning

Before attempting any repairs, it’s crucial to accurately diagnose the cause of your uneven floors.

This will help you determine the best course of action and whether you can handle the repairs yourself or need to call in a professional.

In this section, we’ll provide some tips for diagnosing the cause of your uneven floors.

Inspecting Your Foundation

If your floors are slanting or sloping, it’s important to inspect your foundation for signs of damage or settling.

Look for cracks, gaps, or other signs of movement in the foundation walls, and check the exterior of your home for signs of sinking or unevenness.

If you suspect that foundation issues are causing your uneven floors, you may need to consult a foundation repair company or a general contractor for assistance.

Checking Wooden Supports

For sagging or dipping floors, the problem may lie with the wooden supports beneath the floor.

Check the condition of the beams, joists, and subflooring in your crawl space or basement, looking for signs of rot, damage, or moisture.

If you find any issues with the wooden supports, you may need to shore them up or replace them to fix your uneven floors.

Repair Methods for Uneven Floors in Old Houses

Once you’ve diagnosed the cause of your uneven floors, you can move on to selecting the appropriate repair method.

In this section, we’ll discuss several common repair methods for fixing uneven floors in old houses.

Foundation Repair

If your slanting or sloping floors are caused by foundation issues, you may need to consult a foundation repair company or a general contractor.

They can assess the extent of the problem and recommend the best course of action, which may involve:

  • Underpinning: This method involves strengthening and stabilizing the existing foundation by extending it deeper into the ground or adding additional supports.
  • Mudjacking: Also known as slab jacking, this process involves injecting a mixture of cement, sand, and water beneath the sunken portion of the foundation to raise it back up to its original level.
  • Pier and beam stabilization: For homes with pier and beam foundations, this method involves installing additional piers and beams to provide extra support and stabilize the foundation.

Joist and Beam Repair

If the wooden supports beneath your floor are the cause of your sagging or dipping floors, you may need to repair or replace the damaged beams and joists.

This can involve:

  • Sistering: This technique involves attaching a new, healthy beam or joist alongside the damaged one to provide additional support and stability.
  • Replacement: In some cases, it may be necessary to completely remove and replace the damaged beams or joists with new ones.
  • Shoring up: If the beams or joists are sagging due to insufficient support, you may need to install additional supports, such as piers or posts, to provide the necessary reinforcement.

Floor Leveling Compound

In some cases, using a floor leveling compound can help to even out minor dips or sags in your floor.

This self-leveling compound is a liquid mixture that can be poured onto the uneven areas of your floor, where it will flow and settle into a level surface as it dries.

Keep in mind that this method is generally best for small-scale repairs and may not be suitable for addressing significant structural issues.

Safety Considerations for Fixing Uneven Floors

Floor leveling and repair projects can be major undertakings that can permanently alter your home, so it’s essential to prioritize safety.

Here are some safety tips to keep in mind when working on your uneven floors:

  • Work with an assistant: Always have someone nearby to help you, especially when lifting heavy materials or working in tight spaces.
  • Wear eye protection: Make sure to wear safety goggles or glasses to protect your eyes from debris and dust.
  • Consult a professional: If you’re unsure about any aspect of the repair process, don’t hesitate to consult a professional for guidance and assistance.


Fixing uneven floors in an old house can be a challenging task, but with the right knowledge and tools, it’s possible to restore your floors to a level and stable condition.

By accurately diagnosing the cause of your uneven floors and selecting the appropriate repair method, you can address the issue effectively and ensure the safety and longevity of your home.

And remember, if you’re ever in doubt about your ability to handle the repairs yourself, don’t hesitate to call in a professional for help.

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