# Garage Door Weather Seal & Bottom Seal Replacement > Garage door bottom seal, side and header weatherstripping replaced across Hamilton, Grimsby, Stoney Creek and Burlington. Stops the draft, the blown snow and most of the water, within what a garage door can honestly do. - Canonical HTML: https://gd-concept.pages.dev/services/garage-door-weather-seal/ - Section: Home > Services > Weather seals & bottom seal - Business: Garage Doorman, 6 Chestnut Dr, Grimsby, ON L3M 0C4, Canada - Phone: (905) 536-5369 | Email: info@garagedoorman.ca - Page updated: 2026-08-31 --- The bottom seal, the side stripping and the header stripping are the cheapest parts on a garage door and the ones that decide whether the garage is full of snow in February. We replace all three across Hamilton, Stoney Creek, Grimsby, Burlington and Niagara, and we will tell you honestly where a seal is the answer and where the concrete is. [Call (905) 536-5369](tel:+19055365369) [Water under the door?](https://gd-concept.pages.dev/guides/water-under-garage-door/) ## The three seals, and what each one is for Perimeter weatherstripping on a sectional door | Bottom seal (astragal) | A rubber or vinyl gasket in a retainer along the bottom edge. Takes the most abuse, freezes to the slab, and is the first thing to fail. Usually replaceable on its own by sliding a new one into the existing retainer. | | --- | --- | | Side stripping | Vinyl or rubber flap on wood or PVC stops nailed to the jambs. Stops the draft you can feel standing beside the door, and the wind-driven snow that piles up inside the corner. | | Header stripping | The same product along the top. The most commonly missed one, and the reason a garage can feel drafty with a perfect bottom seal. | | Threshold seal | A separate rubber ramp bonded to the floor, not to the door. Useful where the slab slopes the wrong way, and the one thing that genuinely helps with standing water. | ## The honest limit, stated by the industry This is worth saying plainly because a lot of people are sold a seal to fix a problem a seal cannot fix. DASMA's position on wind-driven rain and sectional doors is that although they "provide some protection against water infiltration, it is important to understand that they are not leak proof or watertight." Source: DASMA Technical Data Sheet [#1503, Wind-Driven Rain and Sectional Garage Doors: Reasonable Expectations](https://www.dasma.com/wp-content/uploads/2025/04/TDS-1503.pdf) (PDF). Checked 31 August 2026. The same document lists three ways rain gets past a closed door: water clinging to the face drips down when the door is opened and the sections articulate; water sitting in the section joints wicks to the ends of the door and bypasses the perimeter seal; and strong wind drives rain straight through the sides, bottom and between sections. Only the last of those is really a seal problem. ## When the slab is the problem, not the seal If water runs under the door in a normal rain with no wind behind it, the door is not what is letting it in. DASMA's recommendation for floor-level water infiltration is a slightly inclined lip or sill for the door to rest on, sloped 3 to 5 degrees, or a rectangular notch in the lip of the slab that the door closes into, below slab grade, at least half an inch deep and sized to take up to a 2-inch-wide track and a 2-inch-thick door section. Source: DASMA Technical Data Sheet [#197, Water Infiltration Under the Bottom of a Sectional Door](https://www.dasma.com/wp-content/uploads/2021/02/TDS197.pdf) (PDF), Door Solution. Checked 31 August 2026. Neither of those is a garage door repair. On an existing slab the practical middle ground is a bonded threshold seal, which raises the barrier at the door line without pouring concrete. It works. It also means you drive over a small ramp, and it can trap water on the outside if the apron slopes towards the garage, which is why we look at the driveway before recommending one. Full detail on [the water guide](https://gd-concept.pages.dev/guides/water-under-garage-door/). ## Signs the seals are gone - Daylight visible along the bottom or up the sides with the door closed. - Snow blown into the garage in a line along the door. - The bottom gasket is flattened, cracked, or torn away from its retainer. - The seal has frozen to the slab and torn on the way up. Very common here in January. - Leaves and grit collecting inside the door line. - Mice. A worn bottom seal is a doorway. ## Insulation, seals and condensation Sealing a garage tighter changes the humidity inside it, and on an insulated door with windows that can show up as condensation. DASMA's advice for controlling it is to maintain proper garage ventilation to control humidity, to reduce the garage air temperature in extreme cold, and to ensure tight seals around the glazing perimeter and door section. Sealing the perimeter is on that list; heating a humid sealed garage is not. Source: DASMA Technical Data Sheet [#195, Garage Doors and Condensation](https://www.dasma.com/wp-content/uploads/2022/03/TDS195.pdf) (PDF), Tips for Controlling Condensation. Checked 31 August 2026. ## What the job involves 1. The bottom retainer is checked. If it is straight and undamaged, a new gasket slides in and the job is quick. If the retainer is bent or corroded, it gets replaced with the seal. 2. Side and header stripping is removed with the old fasteners and replaced onto sound stops. Rotted wood stops get flagged, because new stripping on rotten wood does not last. 3. The door is closed and checked along its whole length for daylight, then adjusted so the seal meets the slab evenly. 4. If the slab is out of level, we say so and talk about a threshold seal rather than pretending a thicker gasket will fix it. Seals are also standard on a [new door installation](https://gd-concept.pages.dev/services/new-garage-door-installation/) and get checked on every [annual tune-up](https://gd-concept.pages.dev/services/garage-door-tune-up/). ### Draft or snow along the door? Best done in autumn. A seal fitted in October is a seal that is not frozen to the slab in January. [Call (905) 536-5369](tel:+19055365369) ### Check it yourself in a minute - Close the door and turn off the garage light. - Look along the bottom, then up each side, then along the top. - Daylight means a gap. - Note whether the gap is even or only at one end: an uneven gap can mean the door is out of level, not that the seal is worn. ### Where we go [Grimsby](https://gd-concept.pages.dev/areas/grimsby/) · [Beamsville & Lincoln](https://gd-concept.pages.dev/areas/beamsville/) · [Stoney Creek](https://gd-concept.pages.dev/areas/stoney-creek/) · [Hamilton](https://gd-concept.pages.dev/areas/hamilton/) · [Ancaster](https://gd-concept.pages.dev/areas/ancaster/) · [Dundas](https://gd-concept.pages.dev/areas/dundas/) · [Waterdown & Flamborough](https://gd-concept.pages.dev/areas/waterdown/) · [Binbrook & Glanbrook](https://gd-concept.pages.dev/areas/binbrook/) · [Burlington](https://gd-concept.pages.dev/areas/burlington/) · [St. Catharines](https://gd-concept.pages.dev/areas/st-catharines/) ## Related - [Water under the door](https://gd-concept.pages.dev/guides/water-under-garage-door/) - [Ontario winter failures](https://gd-concept.pages.dev/guides/garage-door-winter-problems-ontario/) - [Annual tune-up](https://gd-concept.pages.dev/services/garage-door-tune-up/) - [New door installation](https://gd-concept.pages.dev/services/new-garage-door-installation/) - [All services](https://gd-concept.pages.dev/services/) Cheapest part on the door ## Stop the draft before the snow finds it. [(905) 536-5369](tel:+19055365369) [Contact and hours](https://gd-concept.pages.dev/contact/) --- Garage Doorman repairs and installs residential garage doors from Grimsby, Ontario. (905) 536-5369. Full site: https://gd-concept.pages.dev/