A door astragal is a molding or seal installed at the meeting point between a pair of double doors, sealing the gap between the two door slabs when both are closed and often incorporating a mechanism to secure the inactive leaf in place.
This component addresses a specific sealing challenge unique to double door installations, since the vertical gap where two door edges meet requires different treatment than the perimeter weatherstripping used at a single door’s frame connection.
Astragals often include a flush bolt or similar hardware mechanism that secures the inactive door leaf into the frame above and below, allowing the active leaf to be opened and closed independently while the inactive leaf remains fixed in place until specifically released.
What Does a Door Astragal Involve?
- A molding or seal at the meeting point of double doors
- Weatherstripping addressing the vertical gap between leaves
- Often a flush bolt securing the inactive leaf
- Coordination with the overall door hardware and security system
Why Are Door Astragals Important?
Without a properly installed astragal, the vertical gap between double doors would remain unsealed, creating a significant path for air infiltration and, at exterior applications, potential water intrusion at this specific junction point. This sealing function makes the astragal a genuinely important component for double door installations, both for energy performance and weatherproofing.
The flush bolt mechanism often incorporated into or alongside the astragal also serves a security function, since securing the inactive leaf prevents it from being forced open independently, an important consideration for exterior double door security. This attention to hardware detail ensures double doors perform reliably as both a security and weatherproofing feature.
Door Astragal vs. Door Weatherstripping
A door astragal specifically addresses the gap between double door leaves. Door weatherstripping is the broader term covering seals around any door’s perimeter, including the astragal as one specific application relevant to double door configurations.