Attaching to concrete block.
Q I need to attach an upper wall cabinet to a concrete block wall, and in the past, I've had very little luck attaching anything to concrete. What's the best way to do it?
E. Rensch, Sarasota, FL
A At one time, nothing made me doubt my do-it-yourself abilities more than trying to attach something to concrete or concrete block. The really hardened older stuff was the worst. Masonry nails always seemed to chip the concrete slightly, then bend into a "U" instead of going in. Even power nailers that used .22 caliber charges offered mixed results. The one thing I could rely on--concrete anchors that use lag bolts and lag shields--required a heavy-duty hammer drill and a big carbide masonry bit. My frustration ended when I discovered masonry screws.
Masonry screws, often referred to by the brand name Tapcon, have both deep and shallow threads. The shallow threads "tap" the wall of the predrilled hole, starting the groove for the deep threads that take a bigger bite and give the screw holding power. To install them, you need only a 3/16- or 1/4-in. carbide masonry bit (check the Tapcon instructions) and an ordinary drill with adjustable speed (high-speed settings will shorten the life of the masonry bits). Buy screws that are long enough to sink at least 1 in. deep into the concrete (usually 1-3/4 in. to 2-3/4 in. for mounting cabinets).
Before you set your cabinet in place, use a standard 1/4-in. drill bit to drill holes every 12 to 16 inches in the upper and lower mounting strips on the cabinet back. Then set the cabinet, but make sure the predrilled holes do not line up on mortar joints. Use the carbide masonry bit to drill the hole in the concrete. Finally, drive the masonry screw with a power drill (you'll need a No. 3 bit for a 1/4-in. dia. screw), but be very careful not to overdrive it and "strip out" the hole.
[Typically, an upper wall cabinet will be mounted so that the bottom of it is 54 in. above the floor.--S.S.]