Easy Installation of a Window Box


Window boxes come in a variety of shapes and styles, but the one thing they all have in common is that they sit in front of a window. Getting them in that position is often a challenge--particularly if the box is a large one that will be heavier still when filled with soil and plants. Fortunately, it is no more complicated to mount heavy-duty brackets as to use less-sturdy methods to support your window box.

Step 1

Use a stud finder to locate the framing timbers within the house walls beneath the window where you want to install the window box.

Step 2

Measure your window box to determine the number of brackets needed--figuring one bracket for each end of the box, and additional brackets for every 16 to 24 inches between (depending upon the spacing of your house's framework).

Step 3

Measure the height of the window box to determine the distance below the window for placing the shelf brackets.

Step 4

Measure the same distance down from the bottom of the window sill at each of the corner points and draw a straight line across the wall between them.

Step 5

Position one heavy-duty steel shelf bracket against the house wall just beneath and touching the pencil line, at the spot where you located the first stud on the left side beneath the window. Use a pencil to mark points through the holes in the bracket for future placement of screws. Repeat for each bracket working left to right.

Step 6

Drill pilot holes at the marked points (sized slightly smaller than the diameter of the screws you will be using).

Step 7

Screw the brackets to the wall using pilot holes as guides. (Screws should be long enough to penetrate the siding on the house plus at least 1 1/2 inches into the wall stud.)

Step 8

Set the window box on the shelf brackets and use a spirit level to make sure it is level. Adjust the position of brackets if necessary.

Step 9

Mark the locations for screw holes on the bottom of the window box (while it is in place on the brackets). Remove the box and turn it upside down on a flat work surface so you see the marks.

Step 10

Choose a drill bit the same diameter as the holes in the bracket, and drill through the box at the marked points.

Step 11

Choose bolts of the same diameter as the holes, and of a length to penetrate the bracket, window box and enough distance beyond for the nut and washer to fasten.

Step 12

Put the box back on top the brackets, and line up the holes in the box with those of the brackets. Insert one bolt into each hole from beneath the bracket and up through the bottom of the window box, fastening them in place with washers and matching nuts. Tighten the nuts.

Step 13

Fill the window box with soil and plant as desired.

Tips and Warnings

  • In Ask The Builder, building expert Tim Carter recommends using waterproof, heavy-duty window boxes, as well as a water repellent sealer of some sort on the area behind the boxes to prevent potential water damage to your home.

Things You'll Need

  • Stud finder
  • Measuring tape or yardstick
  • Pencil
  • Heavy-duty steel shelf brackets
  • Drill and bits
  • Wood screws (number and size depend upon brackets and wall conditions)
  • Spirit level
  • Bolts with matching washers and nuts


  • Ask The Builder: Window Boxes

Who Can Help

  • Do It Yourself: Window Box in 5 Easy Steps
  • Creative Homemaking: How to Buy or Build Window Flower Boxes
Keywords: installing window boxes, easy windowbox installation, window box brackets, attaching window boxes, window box attachment

About this Author

Deborah Stephenson is a freelance writer and artist, who brings over 25 years of both professional and life experience to her writings. Stephenson features a Bachelor of Arts in Anthropology from University of Arkansas at Fayetteville. She is an anthropologist & naturalist, and has published a field guide on Michigan's flora & fauna as well as numerous political and environmental articles.