Published 2026-05-01 · Houston Garage Door Pros
Garage Door Bottom Seal Replacement: Keeping Houston Heat, Water, and Pests Out
Quick answer: Replace the garage door bottom seal when it is cracked, flattened, or letting in water, light, or pests. Houston heat and UV degrade the rubber faster than cooler climates, and flooding tears and rots it. A new bottom seal is an inexpensive part that protects against water intrusion, summer heat gain, and the insects and rodents that exploit a worn gap.
How to tell it is worn
Look for daylight under the closed door, cracking or flattening of the rubber, water seeping in during rain, or insects and geckos getting through. In Houston the bottom seal takes a beating: UV and heat harden the rubber, and standing water during floods tears and rots it.
A worn seal also lets the conditioned air out and the 100-degree summer air in, which shows up on the cooling bill for attached garages.
The replacement
Most residential doors use a U-shaped or T-shaped astragal seal that slides into a retainer on the bottom of the door. We match the retainer profile, cut the new seal to length, and install it, warming the rubber so it seats cleanly in the Houston heat. On older doors with a damaged or missing retainer, we add a new aluminum retainer.
We also check the threshold and weatherstripping on the sides and top, since a bottom seal alone will not stop water if the perimeter is gapping.
Flood considerations
A bottom seal slows water but will not stop a flood. If your garage floods regularly, a threshold seal on the floor plus the bottom seal gives the best defense against the routine inch or two of bayou backup. For repeated deep flooding, the longer-term fix is a flood-rated door or a barrier system.
Frequently asked
How do I know if my bottom seal needs replacing?
Daylight under the closed door, cracked or flattened rubber, water seeping in, or pests getting through all mean it is time. In Houston, heat and UV wear it out faster than in cooler climates.
Will a bottom seal stop my garage from flooding?
It slows water and stops the routine inch or two, but it will not hold back a real flood. A threshold seal plus the bottom seal is the better defense for minor flooding.
Can I replace the bottom seal myself?
On a door with a good retainer, a handy homeowner can slide in a new seal. If the retainer is damaged or missing, or the door is heavy to manage, it is worth a quick service call.
Does a worn seal raise my cooling bill?
For an attached garage, yes. A gapping seal lets August heat in and conditioned air out, which the AC has to fight.
How long do bottom seals last in Houston?
Less than in mild climates because of UV and heat. Plan to inspect yearly and replace every few years, sooner if the garage floods.