Disclaimer: The instructions which follow are suggested guidelines only as the construction and condition of your walls may vary. A window box that is improperly installed may be a hazard and could potentially cause injury or damage to persons or your property. To ensure years of window box satisfaction and longevity, we recommend you have a licensed contractor or qualified handyman install or advise you.
Iron and aluminum window boxes add greenery and architectural character beneath your windows. Proper window box installation helps create a level, secure display that complements your home for years to come.
The guidelines below cover common window box mounting methods for wood, shake or shingle, stucco, HardiBoard, vinyl, brick, stone, masonry, and block exteriors.
Choose Your Iron or Aluminum Window Box
Before planning your window box installation, choose a box that suits the width of your window and the architectural style of your home. Browse our window boxes or explore the wrought iron window box collection for designs ranging from simple profiles to more decorative cages.
Many iron window boxes are designed to hold separate planting containers. You can also explore compatible window box liners and water reservoirs while planning your display.
Plan Your Window Box Installation
A secure installation begins with the appropriate number of mounting points. Stud spacing beneath windows is not always predictable, so locate the framing before deciding exactly where the cage will attach.
The original window box mounting guidelines recommend the following number of bolts based on box length.
• 24-inch boxes use 2 bolts into studs.
• 30-inch, 36-inch, and 48-inch boxes use 4 to 6 bolts into studs.
• 60-inch and 72-inch boxes use 6 to 8 bolts into studs.
Tools and Materials Needed
Gather your tools before beginning the window box installation. The exact hardware required depends on your exterior surface.
Tools
Materials
• Drill
• 1/8-inch drill bit
• 1/2-inch drill bit for brick or masonry
• Level
• Tape measure
• Pencil
• Electronic or magnetic stud finder
• Socket wrench
• Hammer or mallet for masonry installations
• Iron or aluminum window box
• 3-inch-long, 1/4-inch-diameter lag bolts
• Lag shields for brick or masonry
installations
• For 24" Length Boxes use 2 bolts into studs
• For 30," 36" or 48" Boxes use 4-6
bolts into the studs
• For 60" or 72" boxes use 6-8 bolts
into the studs
If you need additional mounting components for another style of planter, browse our window box brackets and bolts.
How to Complete an Iron or Aluminum Window Box Installation
Step 1. Locate and Mark the Wall Studs
Use a stud finder to locate the studs beneath the window and mark their positions. Studs are often spaced 16 inches on center, but spacing below windows varies. Attach the window box to as many suitable studs as practical.
Step 2. Determine the Window Box Height
Decide how far beneath the window you would like the box to sit. Use a level to draw a straight horizontal line at the desired height.
Placement is largely a matter of design preference. If your window has a projecting water ledge or sill, leave enough clearance to remove and replace liners or pots comfortably.
Step 3. Center the Window Box and Mark the Mounting Points
Hold the cage centered beneath the window with the top aligned to the horizontal line. Mark the predrilled holes in the back of the cage and any usable openings across the double iron strap. These window box mounting locations should align with the studs marked earlier.
If your iron cage does not include a double strap and the existing holes do not line up with the studs, additional holes may be drilled in the iron where necessary. Use a drill bit designed for metal
Step 4a. Drill the Pilot Holes (wood, stucco, vinyl, shake, or shingle)
For wood, stucco, vinyl, shake or shingle, and HardiBoard exteriors, drill 1/8-inch pilot holes at the marked locations. The holes should extend into the studs and are sized for the 1/4-inch-diameter lag bolts specified for this window box installation.
Step 4b. Drill the Pilot Holes (brick, stone, block, or masonry)
For brick, stone, block, or masonry, use a 1/2-inch drill bit at the marked locations. Gently insert the appropriate lag shields with a hammer or mallet before installing the bolts.
Step 5. Secure the Window Box
Use a socket wrench to bolt the cage securely to the wall. Washers over the bolt heads are not required for the installation method shown in this guide. Tighten each bolt until the cage is secure, stopping before the bolt head or mounting point is stripped.
Once the window box installation is complete, check that the cage sits level and feels firmly attached before adding the liner, soil, plants, and water. For other window box styles, visit our complete installation guides.
Frequently Asked Questions About Window Box Installation
Are window boxes bad for your house?
No, if properly maintained. A securely installed window box can add greenery and architectural detail to the façade. Proper mounting, routine care, and attention to the condition of the box and exterior surface help support an attractive long-term installation.
How do you hang window boxes on vinyl siding?
For the iron and aluminum cages covered by this guide, first locate the wall studs behind the siding. Mark the mounting locations, drill 1/8-inch pilot holes into the studs, and secure the cage with the specified lag bolts. Because exterior construction varies, professional guidance may be appropriate for unusual siding or wall conditions.
How to install window boxes on brick?
For the installation method covered here, mark the mounting locations and use a 1/2-inch masonry bit to create the required holes. Insert appropriate lag shields, then secure the cage with the specified 1/4-inch lag bolts. Check that the completed window box installation is level and firmly attached before filling the planter.
How do window boxes attach?
The attachment method depends on the window box and exterior surface. The iron and aluminum cages in this guide use lag bolts through predrilled holes or openings in the cage to create secure window box mounting. Masonry surfaces also require suitable lag shields.
How to install window box brackets?
The iron and aluminum cage method described on this page bolts the cage directly to the wall and does not provide a separate bracket-installation procedure. If your window box uses brackets, follow the installation instructions for that specific product and exterior surface.
