How to Install a Countertop in a Bathroom Without Cabinets Underneath to Prevent Sagging

Anchoring and Wall Studs

• Bathroom countertops are typically 22 inches in depth. You can get by with less, but anything under about 18 inches is more like a shelf. Countertops with at least 22 inches can support almost as much weight as you need -- without sagging -- if it's anchored on two sides with a full anchor along the back. Screw a two-by-four stud to the wall where you wish to install the countertop. Run it full length between the existing fixtures. The stud should ideally tap into all the studs possible inside the wall, but if you can only hit two of them, that should be sufficient on tops no longer than about 36 inches, if the studs are centered under the countertop. One side of the countertop should anchor onto an adjoining wall on the left or right. Screw a stud on either side the same way as the back stud, tapping into at least one wall stud but preferably two.

Countertop Material

• Use particleboard or plywood for the actual countertop. Plywood is lighter, maybe a bit stronger, but more expensive and not as smooth as particleboard. Double the particleboard up to ensure that the top doesn't sag. Place two identical pieces of 3/4-inch-thick particleboard sandwiched together with glue between them. This provides a nice, thick edge allowing you to install laminate directly to the edge. One more advantage of doubling the thickness: You can use a jigsaw to round the corner of the doubled-up particleboard and sand it for a smooth, round countertop edge that's user-friendly in tight bathrooms. Screw the doubled-up particleboard directly to the wall anchor studs for a countertop that can support your own body weight.

Laminate

• Plastic laminates add strength to countertops. Select an appropriate pattern and order laminate at least 1 inch bigger on all four sides than the countertop and order a 1 1/2-inch-wide strip for the countertop edge, also known as the fascia. Brush an even coat of contact cement on the back of the laminate, the countertop and the edge of the countertop. When the glue is dry to the touch, place the fascia directly on the edge, flush with the top. Place the countertop piece on next. It should overhang the edges on the front and side, and flush with the wall in back and on the side that connects to the wall. Tap the laminate with a rubber mallet to bond it, and then use a router with a flush-cutting laminate bit to trim the laminate flush with the edges.

Free-Standing

• If you only have one back wall without access to a wall on either side, you can still install a supported countertop. This type of top uses stud braces set at an angle underneath to support the weight of the countertop. If might not look as stylish, but it will not sag. Start by screwing a stud on the wall along the length of the countertop in back. Cut and place the particleboard top on, preferably doubled-up. Use horizontal studs as legs to support the top initially. Measure up from the floor about 18 inches and make a mark on the wall where wall studs run vertically up behind the countertop. Measure from the mark, angled up and out to the front edge of the countertop. Cut two-by-four studs with angles on both ends so that one end fits flat against the wall, and the other end fits flat against the bottom of the particleboard. Screw the angled stud supports to the wall and to the bottom of the countertop. Apply laminate just as you would any other top.