Seals and Weatherproofing, Long Beach
Water in the garage, grit across the floor, and the rust that eats the bottom of a steel door all start in the same place. A seal is the cheapest part on the whole door.
Water, draughts and pests under a garage door, and what actually stops them.
August 20, 2026
Every rain you get a wet strip across the garage floor. It is not the door failing, it is the seal, and there are only really three causes.
The bottom seal is a rubber or vinyl strip in a channel along the base of the door. It compresses against the slab and closes the gap. It is the hardest working part of the door and it wears out on a predictable schedule.
Sun hardens the rubber and drives out the plasticisers, so it stiffens and splits. Years of compression flatten it permanently. And something driven over a corner tears it.
How to check. Close the door, go inside, turn the light off. If you can see daylight along the bottom, the seal is not closing. Then run a hand along it, feeling for hard, cracked, or flattened sections.
Fix. Replacement, matched to the profile of your channel. Under an hour and the cheapest work on any door.
This is the one that catches people out, because they replace the seal and the water still comes in.
Concrete settles. It cracks, it lifts at a joint, it sinks where the ground under it moved. Plenty of garage slabs also slope slightly toward the door by design, which is good for drainage and bad for keeping water out under wind.
A seal can only compress so far. Where the floor drops away by more than that, the gap is physically un-closeable by a seal alone.
How to check. With the door closed, look along the bottom from inside. If the gap is uneven, wider in the middle or at one end, that is the floor rather than the seal.
Fix. A threshold seal, which is a rubber strip bonded to the floor forming a low ridge that the door seal meets from above. Between them they close a gap neither could manage alone.
Worth knowing it is a small step, so if you wheel bins or a bike in and out you will feel it.
If water only appears in certain storms, particularly from one direction, it is being pushed rather than running in.
That usually means the side and top stripping, not the bottom seal. Wind-driven rain gets past the sides of a door far more easily than people expect, and the top strip is often missing entirely on older garages.
Fix. Perimeter stripping down both jambs and along the header. Often paired with a bottom seal replacement, and together they transform a leaky garage.
Water on the floor is annoying. Water in the bottom channel of the door is expensive.
When a seal stops sealing, water sits in the channel along the base of the door rather than running off. In Long Beach that water carries salt. It stays behind as the water evaporates, works into the seam, and corrodes the steel section from the inside outward.
By the time paint blisters on the outside, the metal underneath has usually gone. That is a section replacement, and if the door model has been discontinued and no matching panel is made, it becomes a whole new door.
So the chain runs: a fifteen dollar strip of rubber, ignored for four years, becomes a section replacement or a door. That is the entire argument for looking at your bottom seal once a year.
Grit and leaves, which is mostly a nuisance.
Mice. They need very little space, and a worn corner on a bottom seal is an open door. Sealing the perimeter is more effective than trapping, because it removes the route rather than the animal.
Draughts, which matter a great deal if the garage has been converted into a gym, office or workshop. Seal before you spend on insulation. An insulated door over an open gap is poor value.
Close the door and turn off the light. Look along the bottom, then the sides, then the top, for daylight. Then look for horizontal lines of light across the door itself, which are cracked joint seals between panels.
Then feel the bottom seal for hardness and cracks, and glance at the bottom of the door for paint blistering or soft spots.
That is the whole inspection. It costs nothing and it catches the one failure on a garage door that turns cheap into expensive.
Call Dakotasungardenswinery at (562) 354-2964.
Two things worth sorting out alongside the seal, because a sealed door over a wet floor still gives you a damp garage.
Check where the water goes. Many slabs slope toward the door, which is exactly what you want, so water that gets in should run back out. If it pools in the middle instead, the slab has settled and a threshold becomes more important, not less, because water that gets in will now stay.
Look at what is outside the door. A driveway that slopes toward the garage, a blocked channel drain, or a downpipe discharging near the opening will defeat any seal in heavy rain. We have fitted seals that solved nothing because a gutter was emptying two feet from the door.
None of that is garage door work, but it is worth ten seconds of looking before you spend on rubber.
If you are dealing with a leaky, draughty garage from scratch:
Doing it in that order means you stop as soon as the problem is solved, and most people stop at step one or two.
Call Dakotasungardenswinery at (562) 354-2964.
Dakotasungardenswinery fits and replaces garage door seals across Long Beach. It is the least glamorous work on a door and it prevents the most expensive failure, because the corrosion that eventually claims a bottom section starts with water sitting where a seal stopped sealing.
The bottom seal is a rubber or vinyl strip in a channel along the base of the door. It compresses against the floor and closes the gap. Over years it hardens, cracks, flattens and tears, and because you never look at it you find out from the puddle rather than the seal.
There are three other seals people forget. Stripping down each side of the opening, a strip along the top, and on an uneven floor a threshold bonded to the slab itself. Together they close a gap that is often large enough to see daylight through.
Four separate gaps, and most doors need at least two of them dealt with.
The strip in the channel along the base of the door. Replaced with a profile matched to your channel type, sized so it compresses properly without dragging the door.
A rubber strip bonded to the garage floor itself, meeting the door seal from below. The answer where the slab has settled, cracked or was never quite level.
Stripping fixed to the jamb down each side and along the header. Often the source of a persistent draught in a garage where the bottom seal has already been replaced.
The rubber between sections that flexes as the door articulates. Cracked joint seals let water and light in across the whole width of the door.
Mice need a surprisingly small gap. A worn corner on a bottom seal is a doorway, and sealing it properly is more effective and less unpleasant than trapping.
If the seal has been gone a while we check what the water has already done to the section above it, and tell you honestly whether it is cosmetic or structural.
Seal and weatherproofing work across Long Beach and the neighbouring Harbor Area cities.
Call (562) 354-2964. If water is already getting in, mention how far it reaches, since that tells us whether a threshold is needed.
The cheapest work we do, and the item with the best return on a coastal door.
Tell us what you are seeing: water reaching a certain distance in, daylight along the bottom, grit blowing across the floor, or a draught. Each points at a different seal, and the fix is usually short, cheap, and considerably less expensive than the section replacement it prevents.