Drilling Masonry 101 – Working With Brick And Concrete.
Drilling Masonry 101 – Drilling into brick and concrete surfaces is standard fare for security installers, particularly when installing external intrusion sensors and CCTV cameras.
That said, achieving precision requires technique, correct equipment, and patience – especially when you’re up a ladder working at height. Masonry is abrasive, variably dense and often strengthened with steel rods, presenting specific challenges not encountered when drilling other materials.
You’ll need good-quality masonry bits, typically tungsten carbide-tipped, designed specifically to handle the abrasive nature of brick, block, and concrete. Standard HSS twist bits will blunt or break off due to heat and friction when working with harder concretes and bricks. They may give you a single drill hole, if that, and heaven forbid you should snap one off flush.
Before drilling, clearly mark your hole position with a pencil or marker. If working on smooth or glazed brick or concrete, it will help to create a small indentation or pilot point with a masonry nail and hammer to prevent the bit going walkabout at the start. You can also start off with a smaller diameter bit then step up.
Hammer drills or rotary hammer drills show their value when drilling masonry. A standard cordless drill may struggle, particularly with reinforced concrete. Whichever tool you use, watch out for overheating.
For brickwork or lightweight blocks, a hammer drill typically suffices. For solid concrete or stone, a rotary hammer drill, with its greater impact and torque, is far more effective. It’s also heavier. If you’re going to be up a ladder carefully plan your weight balance. And think about drill torque and what impact it might have. If you’re using 2 hands on a ladder a powerful drill can throw you off.
Speed control is crucial. Masonry bits perform best at slower rpms. Higher speeds create excessive friction and heat, damaging the bit and producing uneven holes. Start slowly – around 300rpm – and work your way up to 750rpm. This progressive approach preserves your equipment and ensures cleaner, more precise holes.
Using high speed drill bits lets you go up to around 1000rpm, while diamond-tipped bits can go faster still. Something to bear in mind is that the larger the diameter the slower the maximum rpm should be. With heavy work you may need to pause to give the drill motor time to cool down – much depends on substrate density.
Pressure control matters too. Let the drill bit and hammer action do most the work rather than applying excessive force yourself. You need firm but not too much pressure. Pressing too hard or using your body weight – and we’ve all done this towards the end of an exhausting job – can blunt or damage the bit.
You risk breaking the masonry surface around the hole if you lose control of alignment and messing up your job. Instead, allow the bit to progress gradually, speeding up as the drill hole becomes more established. Listen to your drill bit. If the bit shaft starts touching the sides of the hole as you lose concentration or start to tire, you’ll hear it start singing.
Where possible when drilling masonry, use 2 hands, not 1, like the hero in our second image, who has no respect for his wrists. When drilling deep or large-diameter holes, regularly withdraw the bit slightly to clear accumulated dust. This reduces friction, keeps temperatures lower, and ensures holes remain accurately sized and straight.
Fixings in masonry require careful consideration. The hole diameter must match your chosen fixing. Too large, and the fixing won’t hold securely; too small, and insertion risks damaging anchors and surface, as well as failing to hold equipment securely. For heavier applications, masonry anchors or sleeve bolts are required.
In applications with bricks, you’ll need to use plugs to allow fixings to get a bite. Brick isn’t like timber. In fact, after working with masonry, you might find yourself falling in love with wood all over again – it’s just so easy to work with. You’ll find that some bricks, especially older types, can be surprisingly tough to get through.
Anchors are a whole other thing – you’ll end up choosing the anchors you prefer working with for reasons of your own. Whichever anchors you choose, pay close attention to matching fixing and anchor metals to avoid galvanic corrosion. The last thing you want is to cause ugly rust streaks on the fascia of your customer’s beloved office or factory unit.
It’s easier to spray metal parts with Dy-Mark or Zinc It and allow the paint to dry properly than to be faffing around 3-4 years later with bolt heads that have decayed to the point your rattle gun has rounded them and you’re drilling them out. A lot of modern fixings from chain hardware stores are rubbish – even the stainless fixings are suspect. Do your homework.
When you’re working with masonry it’s harder to use drilling jigs or drill presses as you might be able to do on a bench when preparing mounts or doing custom steel work. Concrete core drills are great but mostly for ground work and coring cable access holes. For overhead work there’s a degree of the organic with masonry drilling. It requires good technique, patience, and the right equipment to get fixings right.
When drilling steel reinforced concrete bit choice is paramount. We tend to think it’s best to avoid drilling through steel reinforcement rods wherever possible but construction being the mysterious beast that it is, there are times you may have no choice. There’s going to be a rod right where you don’t want it to be.
You’ll need a rebar cutting bit to make headway in dense reinforced concrete with steel rods and careful technique and the right gear will be vital. If the drill bit slides off a rod surface into surrounding concrete then catches, it’s possible to get nasty torque reactions from powerful drills that will cause serious injuries to wrists and elbows. Power down and take your time.
On the topic of safety, masonry drilling produces dust and debris, which can irritate eyes and airways. You’ll need eye protection, gloves, and a dust mask. There are dust extractor fittings like the Milwaukee SDS Max – your lungs will thank you for using them.
You can find rotary hammer drills here or read more SEN news here.
“Drilling Masonry 101 – Working With Brick And Concrete.”
