A gap under a closed garage door in Richardson usually traces back to slab movement. Clay soil under the foundation swells after rain and pulls back during a triple-digit summer, and that shift can tilt the concrete pad the door closes against. The door itself may be fine while the floor it meets has changed shape. Homeowners in Canyon Creek or Berkner Park often notice it first as daylight along one side, not both.
The Rubber Seal Itself
The black rubber strip along the bottom edge is called the astragal or bottom seal, and it wears out on its own timeline. Sun exposure on a west-facing garage in Richardson dries the rubber out over a few years, and it stops flexing enough to hug an uneven slab. Once it flattens, cracks, or pulls loose from its track, a gap opens even on a door that still opens and closes without trouble. This is the cheapest cause to rule out first.
When the Slab Moved, Not the Door
Richardson sits on dense Blackland Prairie clay, and that ground shifts as moisture levels change through the year. A slab poured level when a house was built can settle or tilt slightly at one corner over decades. When that happens, the garage floor is no longer flat under the door, and no amount of seal adjustment closes a gap caused by concrete sitting lower on one side than the other.
A Track Out of Square
If the slab has shifted, the vertical tracks bolted to the frame can drift out of plumb along with it. A door riding tracks that are no longer parallel will hang unevenly, closing tighter on one side than the other. This shows up as a gap that gets worse toward one corner rather than running even across the bottom, and it usually means the door is dragging or binding somewhere in its travel, not just failing to seal.
Springs Losing Their Lift
Weatherstripping wears out on its own timeline too. Vinyl astragal along the bottom edge hardens after years of North Texas heat, then splits or shrinks away from the slab it once pressed against. Replacing that strip is a separate repair from fixing a crooked track or an out-of-square opening, and mixing the two up wastes money. A tech should check whether the seal is the whole problem before anything gets swapped.
Opener Limits Set Wrong
Some gaps have nothing to do with the door or the slab. Garage door openers use a close-limit setting that tells the motor when to stop pulling the door down. If that limit is set too high, the door stops short of the floor every time, even with a good seal and a square track. This is often the fastest fix on the list, since it is an adjustment rather than a part replacement.
Weep Holes Are Not the Problem
Some garage door bottoms include small weep holes built into the seal to let trapped water drain out instead of pooling under the door. These are intentional and small. If what a homeowner is seeing is a continuous strip of daylight rather than a couple of pinholes near the bottom corners, the seal or the slab is the issue, not drainage design.
Pests Finding the Opening
A gap wide enough to see daylight through is also wide enough for insects, mice, or the occasional larger visitor to get into a garage in Richardson neighborhoods like Canyon Creek or Buckingham. This matters more in the weeks around a Texas heat spike or a hard freeze, when small animals are actively looking for a way into a sheltered space. Closing the gap solves both problems at once.
Testing the Gap Yourself
A gap that only shows up on one corner points to the door binding on a bent track, not a bad seal. Try raising and lowering it by hand with the opener disconnected, and watch where daylight appears as it travels. If the bottom edge sits flush everywhere but a corner still gaps, the rollers or hinges on that side are the likely cause, and a Richardson tech can confirm it on site.
What a Seal Replacement Costs
A new bottom seal is one of the lower-cost garage door repairs available, and the price mostly depends on door width and seal type rather than anything unusual to Richardson. Wider two-car doors need a longer strip, and some styles use a retainer track that costs a bit more than a simple bulb seal. Get a number quoted for the exact door width before assuming a low online estimate applies.
Stop Points Before Calling
A homeowner can safely check the seal for cracking, confirm the gap is even across the width, and look at whether the opener stops the door a few inches high. Anything involving the torsion spring, a bent track, or a door that appears to hang at an angle should stop there. Those point to a repair job better handled by the licensed pros we connect you with.
When It Points to Something Bigger
A worn seal is a small job. A gap tied to a settling slab or a track pulled out of square is a bigger one, and it can keep recurring after a seal swap if the real cause never gets addressed. Homes in older sections of Richardson, including areas near Richardson Heights and Greenwood Hills, are more likely to show slab-related shifting simply because they have had more decades for the clay underneath to move.
Dealing with this in your home?
Slab foundations near Cottonwood Heights and Prairie Creek shift as clay expands after rain, then contracts in triple-digit heat. That movement racks the frame around the garage opening, so tracks bind and rollers wear unevenly. The posts below cover what pulls a door out of true, what a fix costs, and when a panel job beats a full replacement.
