Garage Door Weather Seal Replacement in Boca Raton, FL Astragal and Threshold

What a sectional door can and cannot be expected to do

The honest starting point is that these doors are not watertight, and DASMA states it directly: sectional garage doors are not leak proof, and United States building codes have traditionally set no water infiltration requirement for them. Three paths account for what gets in. Water dripping off the panels when the door is raised, water held in the joints between sections that wicks sideways past the perimeter seal, and wind driving rain through the sides, the bottom, or between sections until it becomes a continuous stream. The window test methods people cite, ASTM E331, ASTM E1105 and AAMA 501.1, are window tests and were not written for doors. The repair list treats each intrusion path separately.

The parts, named correctly

The bottom seal is an astragal, a flexible strip in a retainer on the bottom section, and it is the part that fails first because it takes the abrasion. Side stop molding covers the gap at each jamb and should overlap the jamb by about an inch per side. Header stop molding does the same at the top. A threshold is a separate aluminum or rubber piece bonded to the slab that the astragal meets. Between the sections themselves there are joint seals that most owners never see. Replacing an astragal when the leak is at a jamb is the most common wasted repair on this list.

Slab geometry, and the numbers that make a threshold work

The details are dimensional. DASMA's guidance on infiltration under the bottom describes an inclined lip or sill sloped at 3 to 5 degrees so water runs away from the opening, or a notch in the slab of at least half an inch that accommodates a two-inch track and a two-inch thick bottom section. Where a driveway apron slopes toward the garage instead, no seal will hold against standing water, and the correct answer is a threshold plus a rain lip rather than a thicker astragal. Adjustable jamb brackets matter too, because they let the door be pulled tight to the stop molding instead of leaving a gap the seal has to bridge.

Wind-driven rain against a wide double door

Pressure is what turns a drip into a stream. A sixteen-foot door presents a large area, and during a season that runs from June through November the rain arrives horizontally rather than vertically. Under positive pressure the panels deflect inward slightly, the perimeter seals unload at the moment they are needed most, and water enters at the corners first. This is also why the city's own over-the-counter affidavit for windows, doors and shutters references water infiltration testing provisions in the building code rather than treating water as a cosmetic issue. Enhanced perimeter seals, section joint seals and a threshold together address it, and no single one of them does.

Whether replacing a seal touches the permit question

Seal replacement on its own is maintenance, and it is the kind of work that fits inside the city's exemption for small repairs to a one- or two-family dwelling. The exemption ends where work adversely affects building wind load protection, which includes doors, so a job that begins as a seal and turns into new jamb brackets, new fasteners into the jamb, or a bottom section replacement has changed category and needs to be treated that way. Rust starting at the bottom section behind a failed astragal often points to the panel and door replacement page, and a seal replaced as part of a scheduled visit is described under tune-up and maintenance.