Sagging floor joists can be a real problem for homeowners. Fixing them quickly can help avoid bigger issues later. This guide will help you understand, find, and repair sagging floor joists so your home stays safe and strong.

What Are Floor Joists?

Floor joists are the wooden beams that hold up your floors. They support everything on top, like furniture and people. Here are some common types:

• Wood Floor Joists: Usually made from pine or fir.
• Steel Joists: Strong metal beams used in newer homes.
• Engineered Wood Joists: Made from layered wood like LVL (laminated veneer lumber) and are very strong.

How to Spot Sagging Floor Joists

It’s important to find sagging floor joists early. Here are some signs to look for:

• Uneven or Bouncy Floors: Floors that dip or feel like they move.
• Sticking Doors and Windows: Hard to open or close them.
• Cracks in Walls or Ceilings: Cracks showing up in the drywall.
• Visible Sagging in the Basement or Crawl Space: Joists that are bending or drooping.

What Causes Sagging Floor Joists?

Too Much Weight

Heavy furniture, too many appliances, or lots of weight in one spot can make joists sag.

Moisture Problems

Water can weaken wood. Here’s how:

• Leaks or bad drainage cause water damage.
• High humidity can lead to wood rot.

Foundation Issues

If your house’s foundation shifts, it can affect the joists:

• The foundation settling or moving out of place.

Poor Construction or Age

Old houses or poorly built ones can have problems:

• Using bad materials or just getting old.

How to Check the Damage

DIY Inspection

You can start by checking things yourself:

• Look for Drooping: Check if the joists are bending.
• Measure the Floor Level: Roll a marble to see if it stops or changes direction on its own.
• Check Support Beams: See if they are in good shape.

When to Call a Professional

Sometimes, you need help:

• If Damage is Bad or Cause is Unknown: If it’s severe or you can’t figure out why.
• If Your Home Feels Unsafe: When you’re not sure your home is stable.

How to Fix Sagging Floor Joists

1. Temporary Support

Put in temporary supports like adjustable jacks to stop the sagging while you work.

2. Remove the Bad Joist

Clear the area and carefully take out the sagging joist.

3. Repair or Replace

• Sistering Joists: Add a new joist next to the old one.
• Complete Replacement: Take out and replace the whole joist if needed.

4. Strengthen the Floor

Add more supports or beams to make everything sturdy.

5. Fix the Root Cause

Take care of any moisture issues and make sure weight is evenly spread out to avoid future problems.

Tools and Materials You’ll Need

• Adjustable Jacks: For temporary support.
• Pressure-treated Wood: For new or added joists.
• Fasteners: Nails, screws, and bolts.
• Flashlight and Measuring Tape: For checking things out.
• Safety Gear: Gloves and safety glasses.

Tips to Prevent Sagging Joists

Regular Checks

Look for problems once a year:

• Check floors, support beams, and crawl spaces.
• Look for moisture and pests.

Keep Your Home Dry

Make sure water is kept away from your house and use dehumidifiers in damp places.

Manage Weight Well

Spread out heavy items so they don’t put too much weight in one spot.

Common Mistakes to Avoid

Ignoring the Real Problem

Just fixing the joist isn’t enough. Make sure to fix moisture or foundation problems first.

Using Weak Supports

Get good-quality materials and tools for the job.

Overestimating Your Skills

If things seem too tough, it’s best to call a professional.

When to Get Professional Help

Big Structural Problems

If you see major sagging or lots of joists are affected, call an expert.

Complex Homes

Some homes need special skills to fix properly.

Special Tools and Skills

Professionals have the right tools and know-how for the job.

Helpful Resources

Recommended Experts

• A list of trusted foundation repair professionals in Canada.

Useful Guides

• Links to other helpful articles on Foundation Repair Canada.

By understanding how to spot and fix sagging floor joists, you can keep your home safe and secure. Whether you do it yourself or get help from a professional, acting quickly can save you from bigger problems later.