Hanging a window box to your home is often a difficult task, especially if it is to be directly mounted to the exterior wall. There are several questions you must ask yourself when embarking upon this quest: How much weight needs to be supported? What type of material is the box? What kind of surface is the window box mounting to? What kind of brackets or other supports are available? These are just some of the many questions that need to be answered in order to successfully hang your window box.
Wood and PVC window boxes are generally heavy duty and meant to be able to hold a lot of dirt and support a lot more weight than vinyl. Vinyl is generally not recommended for direct mounting to the house due to the thinness of the material, its susceptibility to cracking, and its lack of structural support. These light duty boxes usually sit atop specialized metal L-brackets that can be directly screwed into the exterior wall.
A heavy duty window box is often mounted one of two ways:
(1) brackets are installed to the home and then the box is secured separately to the brackets or (2) the window box is bolted directly to the home through the back face of the box.
If brackets are used, they are generally functional, although sometimes faux brackets are available that lend no mounting support at all. To mount brackets you will need to begin by measuring the height of the box and offsetting the brackets by that distance beneath the window sill. Next, you will need to measure equal horizontal spacing from the center of the window sill to each side for bracket placement. If the box is longer than 48″, three or more brackets are generally recommended. To hang a window box on siding or stucco, you will want to find the studs and anchor the brackets at those points for the most support. The stud is best found inside the house and under the window with a stud finder. Screw the bracket through the siding with four 4″ thick gauge screws, two at the top and two at the bottom.
To hang a window box on brick, you will need to repeat what was done for stucco. However, unlike stucco, you will need a special “hammer drill” to drill into hard brick. Begin by pre-drilling a 1/4″ hole and then place a 1/4″ drywall anchor in the hole. Screw through the bracket and into the anchor and the bracket will be securely fixed to the wall.
Once the brackets are secure to the wall the window box can then be placed on top and be centered with respect to the window. Finally, drill through the bottom face of the box and directly into the support brackets until secured. It is generally recommended that your window box overhang the width of your window by 1-3″ on each side for aesthetics and to avoid looking disproportional.
If you wish to mount to the home without the use of functional brackets, the steps are very similar. Begin by pre-drilling a hole every 18″ in the back face of the box, preferably near the vertical center. Hold the box up to the window in the appropriate position and mark on the house with a pencil through the pre-drilled holes. Remove the box and then drill 5/8″ holes where you have marked. Place a 5/8″ lead anchor shield into the hole. Hold the box up over the lag shields and screw 3/8″ lag bolts with washers into the anchors until secured. This is the most heavy duty way to install a window box and circumvents bracket failure due to rotting over time. It is not recommended, however to install wooden window boxes this way, because the back of a wooden window box is usually the first part to rot out. This method works well with PVC window boxes made from solid material since they never rot.
Well, now you’re ready to hang a window box. If you haven’t already bought one, now you’ll have all the confidence you need to add value and curb appeal to your home for years to come. Hanging a window box is a fun and empowering task that will allow you to enjoy your window flower boxes that much more.