How to Secure a Window Box
- 1). Run a magnetic or electric stud finder on the wall under the window frame on the inside of the wall to locate studs. Ideally, the studs are located on each corner under the window and right in the middle. When the stud finder signals a stud location, mark the exact spot on the wall using a pencil. Draw a line to extend the three stud marks to the window frame and the wall outside where they are visible, since you will mount the box there.
- 2). Mark the center of the window frame with pencil. Measure the center of the empty window box and mark the point on its upper back edge. Lift the window box and position it under the window frame so its marked center point falls directly above the center of the frame. The point where the two center marks overlap indicates the spot where you will mount the box.
- 3). Support the box firmly with one hand as it rests under the window frame. Ensure its middle mark falls directly on the marked center of the window frame. Transfer the stud marks on each corner of the window frame to the corresponding corner of the box, so like the window frame, the box has a row of three marks along its upper edge. Lower the empty window box and place it on the ground so its back surface faces upward.
- 4). Extend the two corner marks and one middle mark on the box down along the center of the box. Ensure the marks are level before drilling holes through the marks. To drill a hole, position the tip of the drill bit directly above the marked spot and press the power button on the hand drill so it penetrates the wood to form a hole.
- 5). Lift the window box under the frame and extend the marks on the siding using a pencil. Insert the pointed tip of a pencil through a corner pilot hole in the box and mark the corresponding spot on the wall.
- 6). Insert the pencil through the other two pilot holes in the box to mark their locations on the wall as well. Lower the box and place it on the ground. The three pencil marks overlap the stud locations on the wall. Drill a pilot hole through each pencil mark on the siding.
- 7). Glue decorative brackets to the back of the window box. Ideally, the tops of brackets for outward swinging windows fall 5 to 6 inches under the window sill, and for sliding windows fall 1 inch under the sill. Keep the tops of the wooden brackets in line with one another when gluing them to the back of the box. Apply wood glue with a small brush to the back of each bracket and place it over the back of the box. Press it for a minute so the glue adheres to the surface and leave to dry.
- 8). Lift the window box in place under the frame, so the holes along its back overlap the holes on the siding. Insert the threaded end of a 3/8-inch lag bolt into the hole in the washer and bring the washer up to the head of the bolt. Insert the bolt through the corner hole of the box that overlaps the hole in the siding and turn it clockwise with a wrench until tight. Repeat the process for the remaining two bolts and washers.
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