A flush-mounted cabinet simply mounts to the surface of the wall; putting one in is a snap. However, it will probably be shallower than a recessed cabinet, and it will protrude into the bathroom space.
If your bathroom does not have a recessed cabinet, there most likely is a reason. Chances are, plumbing pipes lie directly behind the space, making it impossible to fully recess a medicine cabinet. You may want to settle for a flush-mounted cabinet.
But if every inch of space matters and you want a deeper cabinet, it may be worth your while to open up the wall and investigate whether you can at least partially recess the cabinet. Then you can trim it with molding to give it a finished appearance.
1. Locate the wall studs by using a stud-finding device or by tapping a nail through the wall in places that will get covered up by the cabinet. Mark the location of the studs with a pencil.
2. Mark the position of the top and bottom of the cabinet. Make sure it's reachable by all relevant family members.
3. Temporarily brace the cabinet. With the cabinet door open, use scrap lumber to position the cabinet so it is plumb. Ideally, the studs are positioned so the cabinet can also be centered over the sink.
4. Affix cabinet to wall. Drive screws through the cabinet and into studs. Remove bracing.
Note: Don't just mark a wall and start cutting with a reciprocating or keyhole saw. You may puncture a pipe or sever an electrical cable. If you have the blueprints for your house, they may show the location of pipes and wires. In any case, cut carefully and slowly, feeling for differences in your saw's behavior. To be extra safe, cut a small opening first and check for obstructions with a flashlight and a stick before making the final hole. If you find pipes or wiring, it's easier to install a flush-mounted unit rather than redo plumbing or electrical connections.
1. Shut off power. If the old cabinet has electrical lights or a receptacle, shut off the power at the service panel before proceeding. Remove lightbulbs and electrical cover plates. Disconnect wires and loosen cable clamps so the cable can slide freely through the holes.
2. Empty the cabinet, and look for screws or nails holding the cabinet in place. Unscrew or pry out the fasteners and lift out the cabinet. Avoid damaging electrical cables as you work.
3. Measure the rough opening and look for a cabinet that will fit. In the case of old houses, you may need to enlarge the opening (a messy business) or close it up some. If the flange of the new cabinet does not cover the opening completely, you will need to install molding.
4. Locate studs. Use a stud finder or a hammer and nail to locate the studs. If possible, position the cabinet between studs; otherwise, you will have to cut a notch in a stud to make room for the cabinet.
5. Draw the rough opening of the cabinet on the wall, checking to see that it is level and square. It should be centered over the sink and at a height that will make the mirror usable by all members of your family.
6. Cut the hole for a recessed unit. Score the outline first with a knife and level, then cut it out with a keyhole or reciprocating saw. Remove the drywall or plaster and lath. If there is a stud in the way, notch it to accommodate your cabinet.
Work carefully to avoid cutting through any pipes or electrical cables hidden inside the wall. Blueprints may show you where the pipes are. If there is a plumbing-access panel on the other side of the wall, open it and look around with a flashlight. Cut slowly, feeling for anything that might be a cable or pipe. Though a keyhole saw is slower than a saber saw, it is safer. Notch studs as needed. If electrical cable needs to be moved, shut off the power at the service panel before touching it.
7. Frame the opening. You may or may not have vertical studs to attach the cabinet to. You don't have to frame all around the opening for the medicine cabinet, but you should firmly attach pieces of 2x2 at the top and bottom to secure it. Cut them to fit snugly, and toenail or screw them to the studs. Re-anchor the drywall or plaster to the edge of the studs with screws.
8. If necessary, wire for lights. See instructions for adding lights to a medicine cabinet, below.
9. Set the cabinet. Once the electrical cable is attached to the cabinet, slide the cabinet into place. Check that it is plumb and centered on the sink and sets flush to the wall. Install one of the upper screws and check for plumb again. Make sure the door does not open or close by itself; you may have to shim out the bottom or the top if it does. Attach the cabinet, studs, or other framing pieces by driving screws.
10. Trim a partially recessed cabinet. If you were not able to slide the cabinet all the way flush to the wall because plumbing or wiring was in the way, insert the cabinet so it sticks out of the wall the same distance at all points. Wrap it with molding to cover the gap between the cabinet and the wall.
Depending on the lighting in your bathroom, you may want to add lights at the top of the cabinet or on the sides. And if you find that you have to stretch electrical cords across the bathroom, you may want to choose a cabinet model that comes equipped with a GFCI (ground fault circuit interrupter) receptacle. Installing a simple cabinet will take a few hours at most; adding electrical service and lights can take much longer. If you are not sure of your electrical knowledge and skills, consult with or hire an electrician.
Most cabinets that come with lighting kits have the lights positioned above the mirror, even though sidelights tend to provide better illumination. If the existing light in your bathroom is adequate (if you have multiple recessed fixtures, for example), you likely can get by with a simple cabinet with no lights. If you don't have a nearby outlet, look for a unit with a ground-fault circuit interrupter (GFCI) receptacle.
If local electrical codes allow, you can install a small toggle switch on the cabinet itself. This saves you the trouble of hacking into walls to fish cable and install a standard switch. Do this only if there is room on the face or side of the cabinet for the switch and if there is a cavity available so the cable will not be exposed. Be sure to ground the light -- you'll have to attach the ground wire someplace other than near the switch.
Note: Shut off power before you begin the installation.
1. Run cable to the opening. Run power to the switch, then to the opening.
2. For a light only: Run the power directly to the switch and then to the cabinet. If you will be installing lights only, there's no need to worry about overloading a circuit. However, appliances like hair dryers can require plenty of amperage, so if you are installing a receptacle, make sure the circuit does not service other heavy-amperage appliances or outlets.
Wire connections must be inside a junction box installed in the wall or inside the box that is part of the cabinet. Strip the cable sheathing and the tips of the wire ends. Connect to the wires for the light (black wire to black wire, white to white, and ground to ground). Replace the cover plate and secure the cable.
3. To wire a receptacle and a light: Run power to a junction box, then branch it to the receptacle and switch (see Illustration 1). If you need both a receptacle and a light, wire as shown for a receptacle that is always hot. Provide grounding, either with a ground wire or by means of metal sheathing. Strip the cable sheathing and about 3/4 inch of insulation from each wire. For each connection, twist the wires together with lineman's pliers, screw on a wire connector, and wrap with electrical tape. Connect the ground wire to the screw provided (black to black and white to white). Close the cover.
4. Restore power, and test.