Connecting to concrete

Fastening something to concrete, brick or stone might be intimidating if you haven’t done it before. But the toughest part is drilling the hole. After that, it’s just like fastening to any other material. So don’t be intimidated! With these tips, you’ll be able to attach just about anything to concrete.

Caution: Silica dust can damage your lungs. Always wear a respirator when you’re drilling or cutting concrete or masonry.

Hammer drills often come as a combination driver with a drill, drive and hammer setting. In the hammer setting, a pair of grooved discs rotate, making the chuck slam forward and back as the chuck rotates. This hammering force makes the drill bit chip into the concrete as it spins.

More pressure, more progress

When you’re using a hammer drill, more force equals faster progress. But watch out, these bits can break — ease up if it starts to bend!

Dial in the RPM

With a hammer drill, I find that slower RPM (revolutions per minute) means slower drilling, while higher RPM doesn’t mean faster drilling. The sweet spot is medium-high RPM. My hammer drill has two speed settings, so I use the high setting and nudge the speed up until I find that sweet spot where the bit proceeds at a steady pace.

Learn more with our essential guide to drills.

Rotary hammers are the hammer drill’s big brother. The motor rotates the bit and moves a piston back and forth, which gives the tool more pounding power. Many rotary hammers are multifunctional, adding drill and hammer to the basic rotary hammer function, making them far more useful.

If you have lots of drilling to do, a rotary hammer will cut your labour considerably. You can buy a rotary hammer starting at about $100.

Let the tool do the work

Unlike with a hammer drill, you don’t need to put your weight behind a rotary hammer. Too much force reduces the effectiveness of the piston motion. Apply just enough pressure to make steady progress.

You’ll find a dozen fastener choices at the hardware store, all suited to different tasks. The most important thing is to drill the proper hole size for your fasteners.

I choose concrete screws for most fastening jobs because they’re easy to use, strong and removable. They range in diameter and length.

Pro Tip: An impact driver is my go-to tool for driving concrete screws. It’s the only way to go!

Learn how to lubricate screws to make them easier to drive in.

Plastic anchors work the same in concrete as they do in drywall — press the anchor into the hole and it expands for a snug fit as you drive a screw into it. Plastic anchors are the cheapest option. They’re best for light-duty tasks like hanging small pictures and shelf brackets.

Used for heavy-duty fastening or hanging, sleeve anchors are permanent, really strong and less expensive than large concrete screws. They can be used in any concrete or masonry and have either a screw head or a nut to tighten. The sleeve expands as you tighten the nut for a firm grip.

Wedge anchors provide the strongest connection for demanding jobs like fastening structural hardware to concrete. Hammer the anchor into the hole, then turn the nut to lock the anchor in place. Don’t use wedge anchors in brick, block or mortar joints. The force may cause cracking.

Drill your hole at least 6mm deeper than the length of your fastener (13mm deeper for fasteners 9.5mm or larger in diameter). This ensures that your fastener won’t bottom out because of dust or other debris in the hole. If your drill doesn’t have a depth gauge, wrap a tape flag around the drill bit so you know how deep to go.

These are the 12 most common mistakes when pouring concrete.

So you’ve drilled your hole and for some reason your fastener doesn’t grab. Before throwing in the towel, try these options:

Add a Wire. Push a copper wire into the hole, then drive your concrete screw.

Drill a bigger hole. Upsize the hole and drive in a bigger fastener. You may also need to drill out the hole in the parts you’re fastening.