How to Drill Into Concrete
from wikiHow - The How to Manual That You Can Edit
Drilling a hole into concrete is not much different from drilling into
wood. You can use your handheld drill, but if you have large holes (1/2
inch/ 1.2 cm) or larger), or many holes to drill, consider renting a
hammer drill or rotary hammer. You will need a carbide-tipped masonry
drill bit the size of the hole.
- Start with a small diameter masonry bit.
- Insert drill bit into drill.
- Set the clutch to the highest number.
- Mark the drill bit with masking tape at the length you want the hole deep.
- Keep the drill perpendicular to the surface.
- If using a standard drill, pull the
drill out and back in every ten seconds. This acts as a hammer to get a
bite on the concrete.
- If progress is slow, you hit an aggregate. Insert a masonry nail, hit with hammer to break the aggregate.
- After drilling pilot hole finish with desired bit size.
- Blow out any concrete debris with a large air hose or compressed air in a can or vacuum it clean.
- If your progress is too slow, use a smaller drill bit and drill a pilot hole.
- Many drills feature depth gauges. Use
them. If your drill doesn't have one, try wrapping masking tape around
the bit at the desired depth of penetration.
- When going to purchase a masonry drill
bit, there are two types. Multi-purpose, and those that are exclusively
for hammer-type drilling. The hammer-type bits will not drill into
concrete using regular, non-hammer type drills.
- Do not bear down on the drill with all
your strength. Not only will smaller bits break, but the chisel-type
tip for regular, non-hammer type drilling will create an advantageous
- When using a hammer drill, you only need to withdraw the bit occasionally to remove concrete dust.
- Running a small amount of water over the
area while drilling will reduce the heat of the bit and the friction
between the sides of the concrete and the drill.
- A good quality drill with a pulse hammer
setting will finish a hole in 5 minutes. A cheap battery drill will
take 45 minutes or more. Based on personal tests drilling four holes
for mounting a cabinet into thirty year old apartment-type concrete
- Screw into the mortar between blocks, if
possible, as it is much easier to drill into mortar than concrete
block. Always use lead anchors to hold the screws into place if you
drill into the mortar, as screws set in mortar will work themselves
loose over time. For some applications (electrical boxes, conduit
straps) standard "Tapcon" concrete screws (without anchors) are
adequate. (These screws are easy to identify, as they are blue in
color.) For any application where the screw will be subjected to weight
(such as a bench, handrail or shelves) heavy duty lead anchors should
be driven with a hammer into the holes and then screws driven into the
- While it is possible to drill into
concrete or brick with a standard drill, it is not advisable to try.
The reason is that a standard drill acts on the principle of slicing
into a fibrous material (like wood) or shaving off layers of metal
(like aluminum and steel) and concrete/brick is not fibrous or composed
of layers of material. Concrete/brick is a composite aggregate material
(small rocks bound together with cement) for concrete, and minerals and
stone bound together by heat for brick. To drill a hole in cement/brick
requires two separate actions, hammering to break the aggregate, and
drilling to scoop out the debris. This two stage process requires a
hammer drill to accomplish properly. Usually attempts to drill into
brick with a standard drill results in: 1) no holes actually being
drilled, and 2) the motor of the drill overheating and the drill being
- For very large holes (greater than 3/8
of an inch), or to drill many holes of any size, a rotary hammer is
needed. These are large, piston hammer-drills, which have the advantage
of being able to be used in "hammer only" mode. This mode allows them
to be used to chip concrete and brick as well as drill into it.
However, rotary hammers are usually very expensive and require special
drill bits (SDS, SDS Max and Spline Shank being the most common).
Nevertheless, to drill lots of holes, very big holes, or both, a rotary
hammer is essential.
- Protect your eyes with goggles when drilling and cleaning out the dust and debris.
- The older the concrete, the harder it will be to drill.
- When attempting to break aggregate with a
masonry nail, take care not to drive the nail too deeply, otherwise it
will be difficult to remove. Do not hammer with a flat-head screw
driver. The wide edges of the screw driver's tip will produce gaps in
the concrete which will weaken your anchor.
- When using water, be careful not to get the motor of your drill wet.
- Take care not to breathe in the dust. Work only in well-ventilated areas and take all necessary precautions. Use a dust mask.
- Be aware that stone in concrete can explode and expel chips into your face.
- Be aware that masonry bits get very hot. Wear heavy gloves when drilling into concrete or brick.
- Hammer drilling into concrete or brick is very noisy. Wear ear protection even if you are only drilling a couple of holes.