How to Fix Gap Under Garage Door and Keep Out Pests, Water, and Drafts

If you’ve spotted daylight peeking through the bottom of your garage door, or you’re dealing with water, insects, or even rodents slipping inside, you’re not alone.

A visible gap under your garage door can lead to unwanted problems like moisture damage, heating loss, or even a flood during heavy rain. Let’s look at why it happens and how to fix the gap under your garage door quickly and efficiently.

Why Is There a Gap at the Bottom of the Garage Door?

The most common reason for a gap at the bottom of the garage door is an uneven garage floor or a worn-out seal. But there are other culprits too:

• Shifting Concrete: Over time, your garage floor or driveway may sink or crack due to settling or drainage issues.
• Worn Weatherstripping: If the rubber seal has gotten brittle, torn, or flattened, it may not close properly along the bottom.
• Misalignment: Your door might be slightly skewed due to a bent track, roller issue, or improper installation.
• Improper Installation: If your garage door wasn’t installed correctly, it may never have sealed properly to begin with.

Many homeowners in The Woodlands, Texas, may notice gaps under their garage doors due to uneven concrete, frequent weather changes, or natural settling of the structure.

How to Fix the Gap in Your Garage Door

Step 1: Inspect the Bottom of the Garage Door and Measure the Gap

Before jumping to conclusions, inspect the entire bottom of the door and check how wide the gap is. Take note of whether it’s wider in one area or consistent all the way across. A level can help you see if the door is straight or if the slope of your garage floor is causing the issue.

• Use a flashlight to examine the seal and weatherstrip
• Measure the width and length of the gap
• Check for cracks or high spots in the concrete floor

Step 2: Replace or Add a Seal on the Bottom

A damaged weather seal is a simple but often overlooked reason there’s a gap. Replace it with a new weatherstrip or rubber seal. Some seals are thicker and better suited for uneven garage floors.

• Look for a strip made of natural rubber or vinyl
• Thicker options work better for filling wider or uneven spots
• Use weatherstrip adhesive or screw it into the bottom of your door

You’ll want to keep your garage sealed tightly, especially during heavy rain or cold months when moisture and insects become a concern.

Step 3: Install a Garage Door Threshold

If your gap is due to concrete settling or if your driveway has too much slope, consider installing a threshold directly onto the garage floor. This is a rubber or vinyl strip that bonds to the concrete and forms a barrier.

• It prevents rainwater from flowing in
• Acts as a flood barrier in case of water drainage problems
• Helps block out rodents, leaves, and insects
• Great solution when your door is level but the floor isn’t

Make sure your threshold is tightly bonded and thick enough to eliminate the gap.

Step 4: Adjust or Reinstall the Overhead Door

If your door closes unevenly or the gap consistently reopens after sealing efforts, the cause may be roller wear, misalignment, or a bent track. A professional can perform an adjustment, inspect each bolt, and ensure the opener is functioning correctly.

Sometimes it’s as simple as having the bottom seal installed slightly off. A badly installed rubber flap won’t create a proper seal.

To avoid ongoing DIY trouble, it’s best to call a professional for precision alignment and long-term solutions.

Creative DIY Tricks to Temporarily Fix a Gap

If a full repair is not in the cards just yet, some homeowners get creative:

• Pool noodles – Cut and place beneath a loose threshold or seal for a tighter temporary fit
• Foam tape – Works inside garage door panels to create added pressure when closed
• Door gasket kits – Good for sealing both bottom and sides of the garage door

These DIY options aren’t long-term solutions but can help fix a gap temporarily while you explore more durable repairs.

When to Call a Garage Door Company

If you’ve tried to fix this problem on your own but still have a gap between the bottom of your garage door and the floor, don’t wait for it to grow worse. Misalignment or track damage can get worse over time and even impact your opener or cause the door to not close properly.

A trained technician can:

• Inspect the concrete for slopes or cracks
• Grind high spots on the floor for better closure
• Replace weatherstripping and rubber flaps with proper installation
• Add or replace weatherseal or threshold to keep your garage sealed

In The Woodlands, many homes experience door gap concerns due to humidity and shifting soil. A garage door company familiar with the area understands these conditions and knows how to fix the gap effectively.

Keep Your Garage Sealed and Protected

Fixing a garage door gap does more than improve appearance; it helps eliminate moisture exposure, keeps out insects and rodents, and prevents a potential flood. 

Whether it’s replacing a worn strip, addressing a concrete slope, or installing a seal on the bottom, these fixes keep your garage functioning the way it should.

If you’re unsure where to start, or if a DIY fix hasn’t done the trick, it’s smart to reach out for professional garage door repair services to get expert assistance. It’s the best way to ensure your overhead door, equipment, and seal are working together to keep your home protected.