Installing a Wall Shelf
Empty wall space is often filled with mundane artwork, but a variety of wall shelf units are available that are not only decorative but can also provide a variety of practical function. An example is the shelf/ coat rack/ picture frame combination we've selected here.
The most difficult part of hanging such a shelving unit is getting the position of the hanger screws exactly correct. Most commercial shelving units come with premounted hanger brackets on the back of the frame—ours uses a pair of keyhole brackets. These are shaped so that the shelving unit can be slipped over the heads of support screws driven into the wall, then locked into place by allowing the shelf to slide down over the heads of the screws. Unless the wall screws are installed precisely, the shelving unit won't fit correctly.
Wooden shelving units can be quite heavy, especially if they are large and long, so it is important that the unit is firmly supported. The strongest method is to drive the support screws directly into wall studs. In most framing, the studs are positioned so they are 16 inches apart, measured on center. So if your shelving unit has hanger brackets spaced 16, 32, or 48 inches apart, it may be possible to drive the support screws directly into the studs.
But in many instances, this won't be possible, and you'll instead need to place the support screws in the cavities between studs. A variety of wall anchors are available that can do the job, but the best one for his application is what is known as a hollow wall anchor, sometimes called a Molly bolt. This is the method demonstrated in our project.
Tools and Supplies You Will Need
- Tape measure
- Carpenter's level (2-foot for a short shelf, 4-foot for a longer shelf)
- Drill with 9/32-inch twist bit
- (2) hollow-wall anchors with #6-32 screws, 2 3/8 inches long
- Phillips screwdriver
Determine Position of Shelving Unit
First, you'll need to position the shelf on the wall. With a unit such as the one we are installing, the shelf and coat hooks should be at a height that is easy to reach. Standard practice is to place picture frames roughly at eye level.
- Enlist the aid of a helper to hold the shelf in position against the wall as you eyeball its location. Place a carpenter's level on the shelf to ensure the shelf is exactly level.
- When satisfied with the position, use a pencil to lightly outline the top and the sides of the shelf unit on the wall.
- Set the shelving unit aside.
Mark a Wall Anchor Reference Line
The next few steps will be critical, since here is where you will mark and install the wall anchors for hanging your shelf. Measurements need to be quite precise, since even a small error will make the process much more difficult.
- Turn the shelving unit back-side up, and carefully measure the distance between the top of the shelf and the top of the keyhole opening on the hanger bracket. In our example, this distance is about 2 inches.
- On the wall, measure down from the shelf outline and mark a point matching this distance.
- Using a carpenter's level, make a second reference line across the wall through this point. This line should be exactly parallel to the shelf outline, and run all the way across from one side outline to the other. This will be the reference line you use to drill and install wall anchors and support screws.
Measure and Mark the First Wall Anchor Location
In this step, you'll be determining the exact position of the wall anchors and support screws.
- On the back of the shelf, precisely measure the position of the hanger bracket keyhole slots relative to the side of the shelving unit. Be very precise with the measurement, measuring exactly to the center of the slot. In our example, this distance is about 1 7/8 inches.
- On the wall anchor reference line you just drew on the wall, measure in from the side outline a distance exactly equal to this measurement, and make a mark. This will be the precise location for the first wall anchor. It exactly matches the position of the keyhole hanger on the back of the shelf.
Measure the Distance Between Hanger Brackets
Perhaps the most critical step is this one: making sure the anchor for the second hanger bracket is spaced perfectly in relation to the first anchor.
On the back of the shelving unit, take a precise measurement between the hanger brackets, measuring from the center of each keyhole slot. In our example, this distance is about 23 3/16 inches.
In the next step, you will now transfer this measurement to the wall.
Mark the Second Wall Anchor Location
On the wall anchor reference line, measure from the first wall anchor location and make a second mark on the reference line, so that the distance between the marks exactly matches the measurement you just made between the keyhole brackets on the shelf unit.
Test-Fit the Wall Anchor
There are several options for wall anchors, but the best one for this application is an expandable metal hollow-wall anchor, commonly known as a Molly bolt. Some types of hollow-wall anchors have pointed tips that can simply be pounded through drywall, but we will be drilling pilots holes to avoid the possibility of wall damage. And if you have plaster walls, drilling pilot holes is mandatory.
Before continuing, test-fit the screw heads in the keyhole bracket slots. The wider part of the keyhole should fit easily around the screw head, and the screw should slide easily down so the head fits behind the narrow throat of the keyhole.
Our project uses a #6-32 screw, 2 3/8 inches long, which is a perfect fit for the keyhole brackets on our shelf. You may find that a different size works better for your shelf unit.
Install the Wall Anchors
Installing the wall anchors is the next step in the shelf's installation. You will need to drill a pilot hole in the wall for each of the two mounting holes you marked in previous steps.
- Select the appropriate size drill bit for the wall anchor used. For the #6-32 wall anchor we're using, the matching bit size is 9/32 inch.
- Drill a clean and precisely placed hole into each of the two wall anchor locations marked on the wall. It is quite important to center the drill hole exactly on the points you marked.
- Insert an anchor into each hole and tap lightly with a hammer to seat the pointed prongs of each anchor into the wall surface. These prongs keep the anchor from turning when the screw is tightened.
- Tighten the anchor screw fully, allowing the expanded metal frame behind the wall surface to expand and draw up tight against the back of the wall.
- Once each screw is fully tightened, back them out so the heads extend out 1/8 inch to 1/4 inch. This will allow the screw heads to fit into their respective keyhole slots in the hanger brackets.
- Clean up all the drywall dust from the drilling and erase the pencil marks from the wall.
Hang the Shelf
All that's left to do once the wall anchors are in place is to carefully align the wall shelf keyhole brackets over each hanger screw and slide the shelf down so that the brackets fit tightly over the heads of the screws. If you have trouble getting the brackets to fit over the screw heads, you may need to extend the screws away from the wall a bit more.
Your wall shelf is now ready for use.