How to Attach Window Boxes


Window boxes are an attractive way to add color and charm to the exterior of a home. Bringing flowers and plants up to window level will soften the hard lines of the home and make an inviting impression. From inside the home, window boxes bring color right to the window, making the garden seem part of the room. These bright and colorful displays will last all summer when properly tended. It's important to hang your flower boxes securely so that they don't damage the home or become loose.

Step 1

Measure the width of your window and mark the center line and outside lines of your flower box. Read any mounting instructions that come with your flower box or hangers to check for special mounting instructions.

Step 2

Move a stud finder along the wall if your home is made of siding. You will want to bolt the flower box directly to a wall stud for security. You should be able to locate at least two studs in the wall under a window. The studs should be every 16 inches apart, on center. Mark an X on the siding where you have located each stud. There will also be solid wood directly under the window but this may be covered by protruding trim.

Step 3

Place a level over your stud marks and draw a 12-inch vertical line. This will assist you in positioning several bolts into the stud. Generally, you will want the top of the flower box to be below the window sill (where the rain water runs off the window). Position the box so there is a gap between the box and the wall to allow moisture to escape and not be trapped to rot the siding.

Step 4

Position your flower box hanger or bracket over the vertical line. Some types of boxes will not have hangers and these will bolt through the flower box directly. Mark the location of your bolt holes for each stud. Make sure your box will be level. Drill through the siding and into the stud. Your drill hole should be smaller than your bolt size. For masonry walls, use a masonry drill bit when drilling your holes, which should be the same size as your wall anchors.

Step 5

Add deck to wall spacers between your flower box and your wall. Apply a bead of silicone behind the spacer for siding installations. Apply silane or siloxane water repellant over masonry installations plus using the spacers. Insert wall anchors in brick walls. Insert stainless steel bolts into the holes and tighten with a socket wrench.

Things You'll Need

  • Tape measure
  • Stud finder
  • Pencil
  • Level
  • Drill
  • Masonry bit
  • Wall anchors
  • Deck to wall spacers
  • Silicone
  • Silane
  • Silocane
  • Socket wrench


  • Ask The Builder: Window Boxes
  • Screw Products: Deck To Wall Spacers
Keywords: attach window box, mount window boxes, brick window boxes

About this Author

F.R.R. Mallory is a senior at UC Berkeley completing degrees in both Neuropsychology and English. She has been published since 1996 in both nonfiction and fiction, books, short stories, articles and essays. Her fiction short story "Black Ice" recently won a National Space Society contest.