How to Install High Security Interlocking Astragals on Your Doors

Interlocking astragals discourage thieves by making doors very difficult to pry open. Installing the right astragal for your door type, and installing it properly are both important to ensure effective security.

Determine Which Astragal Set You Need

Outswing astragals are installed on the outside of your door. For doors that open into the building, use the 2 piece inswing astragal. Most doors will swing outwards so you can choose between the regular 2 piece or 3 piece astragal set.

The 3 piece astragal set is for use in double doors, or for doors where there is space on the opening side for a long prybar – such as when the door is flush with an exterior wall. Doors near a wall corner or inside an alcove do not need the 3 piece astragal set as there is not enough room to pry under the 2 piece astragal from the side.

Astragals are available in hammertone finished steel and stainless steel. Stainless steel is typically used for aluminum and glass storefront doors.

There are two standard door height sizes which are 79 or 83 inches. Determine the height of your door to determine the full length astragal length you need.

Installing Your Interlocking Astragals

Use the installation diagram shown on the product page for the astragal set you are installing. The two keys to proper installation are to make sure the door opens freely and the astragals are within about 1/8″ of each other when the door is closed to prevent prying.

Once you have determined the position of your astragals and marked your mounting holes on the door and frame, you are ready to install them.

For the door mounted astragal, predrill the door right through with a 3/16″ bit. Then drill your final 5/16″ holes and bolt the astragal plate to the door with carriage bolts right through the door.

Door frames are typically either hollow or concrete filled steel. For the door frame astragal, predrill your holes with a 3/16″ bit to a depth of 1/2″ through the metal frame and into the concrete inside the frame. If the frame is concrete filled, drill through the metal with a regular bit and then use a concrete drill bit to get to your 1/2″ depth. Then, you can use self tapping screws or rivets to attach the astragal plate to the frame.

Get the Right High Security Astragal for Your Door

  1. 2 piece interlocking astragal for installation on the outside of doors that swing inwards into the building.
  2. 2 piece interlocking astragal for installation on the outside of doors that swing outwards. This is the most common astragal set needed.
  3. 3 piece extra secure astragal for installation on the outside of doors that swing outwards. This is the same as the 2 piece above but adds a 3rd interlocking piece for extra heavy-duty security.