A garage door should sit relatively flush against the floor when it is fully closed. If you can see daylight underneath it, feel cold air coming in, or notice water, leaves, or pests getting through, something may need attention.
A gap under garage door panels is not always caused by the door itself. The problem may be as simple as worn weatherstripping, but it can also indicate an uneven floor, incorrect opener settings, damaged tracks, poor door balance, or another mechanical issue.
At Unwin Overhead Doors, we help homeowners throughout Western Massachusetts identify garage door problems before they become larger repairs. Here are the most common reasons a gap develops under a garage door and what can be done about it.
1. The Bottom Weather Seal Is Worn Out
The bottom weather seal is the flexible strip attached to the lower edge of the garage door. Its job is to create a barrier between the door and the garage floor.
Over time, that seal can:
- Crack
- Flatten
- Harden
- Tear
- Shrink
- Pull away from the door
New England weather can be especially hard on rubber and vinyl components. Cold winters, summer heat, moisture, and repeated compression can gradually reduce the seal’s effectiveness.
Signs the bottom seal may need replacement include:
- Daylight visible along the bottom of the door
- Cold drafts
- Leaves or debris entering the garage
- Water coming under the door
- Sections of the seal hanging loose
- Visible cracks or deterioration
If the door itself is closing evenly and the gap is relatively small, replacing the bottom weather seal may solve the problem.
2. The Garage Floor Is Uneven
Sometimes the garage door is perfectly level, but the concrete underneath it is not.
Garage floors can settle, crack, slope, or wear over time. Even a relatively small change in elevation can create a visible opening under one section of the door.
You may notice that:
- One side seals correctly while the other has a gap
- The gap appears only in the middle
- Water collects near one section of the door
- The door itself appears level when closed
In these situations, replacing the weather seal alone may not completely solve the issue.
A larger or more flexible bottom seal may help accommodate minor variations. In other cases, a garage door threshold seal installed on the floor may provide an additional barrier.
Before changing the door’s adjustment, it is important to determine whether the problem is actually the door or the concrete underneath it.
3. The Garage Door Is Not Closing Far Enough
Your garage door opener has travel settings that determine how far the door moves before stopping.
If the downward travel is set too short, the opener may stop the door before the bottom seal reaches the floor, leaving a consistent gap under garage door sections across most or all of the opening.
Possible signs include:
- A relatively even gap across the entire door
- The door otherwise operating normally
- No obvious damage to the springs, tracks, or rollers
- The bottom seal still appearing to be in good condition
However, opener settings should not automatically be adjusted just because the door is not touching the floor.
If the opener recently began stopping early, another problem may be causing resistance. Worn rollers, track issues, poor balance, or opener problems can also prevent the door from completing its normal closing cycle.
If you are unsure of the cause, professional garage door repair is the safer approach.
4. The Garage Door Is Crooked or Out of Balance
A gap on only one side of the garage door may indicate a balance or alignment issue.
Garage doors rely on springs and cables to lift and lower the door evenly. When a cable becomes loose, a spring weakens, or another component fails, one side may sit higher than the other.
Signs of a balance problem include:
- One corner of the door sits above the floor
- The door looks tilted
- One side opens before the other
- The door shakes while operating
- A cable appears loose
- The door feels unusually heavy
If the garage door is visibly crooked, do not try to compensate by changing the opener settings.
The mechanical issue should be repaired first.
Garage door springs and cables operate under significant tension and should be serviced by a trained technician.
5. The Tracks May Be Misaligned
Tracks guide the rollers as the garage door moves.
If a track becomes bent, loose, or misaligned, the door may not sit correctly when it reaches the floor.
Track problems may result from:
- A vehicle bumping the door or track
- Loose mounting brackets
- Repeated operation of an uneven door
- Worn rollers
- General wear
You may also notice:
- Scraping noises
- Jerky movement
- Rollers binding in the tracks
- Uneven spacing along the sides of the door
- One side of the door failing to close completely
Track adjustment is not something to guess at. Incorrect alignment can make the door bind or create additional strain on other components.
6. The Door or Panels May Be Damaged
Impact damage can also prevent a garage door from sealing properly.
A vehicle, lawn equipment, snowblower, or other object can bend a panel enough to change the shape of the bottom edge.
Look for:
- Dented lower panels
- A bent bottom section
- Cracks or separation
- Damage near the corners
- A bottom edge that no longer appears straight
Minor cosmetic dents may not affect operation. However, structural damage to the bottom section can prevent the door from making consistent contact with the floor.
Depending on the extent of the damage, the solution may involve panel repair, panel replacement, or a new garage door.
Explore Unwin’s Residential Garage Doors if your existing door has significant damage or is approaching replacement.
Why You Should Fix a Gap Under Your Garage Door
A small opening may not seem urgent, but it can create several problems over time.
Water Intrusion
Rain and melting snow can enter underneath the door, potentially damaging stored belongings and creating wet garage floors.
Cold Air
In Western Massachusetts, gaps can allow significant cold air into an attached garage during winter.
That can be especially noticeable if:
- There is living space above the garage
- The garage shares walls with the home
- Plumbing runs through the garage
- The garage is heated
Pests
Mice, insects, and other pests need surprisingly little space to enter.
A damaged weather seal or open corner can provide an easy entry point.
Leaves and Debris
Wind can push leaves, dirt, dust, and other debris underneath a poorly sealed garage door.
Energy Efficiency
If your garage is attached to your home, improving the seal around the door can help limit outside air infiltration.
For homeowners concerned about insulation as well as sealing, explore our residential garage door options.
Can You Fix a Garage Door Gap Yourself?
It depends on the cause.
Replacing deteriorated weatherstripping can sometimes be a reasonable maintenance project for an experienced homeowner.
You can also safely inspect:
- The condition of the bottom seal
- Whether the floor appears uneven
- Whether debris is preventing the door from closing
- Whether the door looks level
- Whether the gap runs across the entire door or only one section
However, avoid DIY adjustments involving:
- Springs
- Cables
- Tracks
- Door balance
- High-tension hardware
If the door looks crooked, feels heavy, shakes, or stops before reaching the floor, the gap may be a symptom of a larger mechanical problem.
When Should You Call for Professional Garage Door Repair?
Contact a professional if:
- The gap appears only on one side
- The garage door is visibly crooked
- A cable appears loose or damaged
- The door does not close completely
- The opener stops before the door reaches the floor
- The tracks are visibly bent
- The door shakes or jerks during operation
- Replacing the weather seal does not solve the problem
A recurring gap under garage door sections should be diagnosed rather than simply covered up. Fixing the underlying cause helps ensure the door operates safely and seals properly.
Unwin provides professional garage door services and repair throughout Western Massachusetts.
Keep Water, Weather, and Pests Outside Your Garage
If you notice daylight or outside air coming in beneath your garage door, start by inspecting the bottom weather seal and the garage floor. A worn seal may be the entire problem, but an uneven gap can also point to balance, track, opener, or door damage.
Addressing the issue early can help keep your garage cleaner, drier, more comfortable, and properly secured.
Unwin Overhead Doors provides garage door repair, maintenance, opener service, and new residential garage doors throughout Western Massachusetts.
Contact Unwin Overhead Doors or call (413) 598-8844 to schedule garage door service.
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