How to Fix Screws Into Brick and Concrete Walls (Without Them Coming Loose)

How to Fix Screws Into Brick and Concrete Walls (Without Them Coming Loose)

Drilling into a wall is easy.

Getting a screw to actually hold properly?

That’s where most people mess it up.

Loose plugs, spinning screws, brackets falling off — it usually comes down to a few small mistakes that make a big difference.

Get it right, and it’s solid for years.Get it wrong, and it’s coming out sooner or later.

Start With What You’re Drilling Into

Brick and concrete aren’t forgiving.

You’re not screwing into timber — you’re creating a fixing point inside a solid material.

That means everything has to be accurate:

• The drill bit size

• The plug

• The depth

• The technique

If one of those is off, the whole fixing is compromised.

The Most Common Mistake (And Why It Fails)

The biggest issue?

👉 The hole is too big

That usually happens when:

• The wrong drill bit is used

• The drill is wiggled while drilling

• The hole gets widened without realising

Once the hole is oversized, the plug can’t grip the wall properly.

And if the plug can’t grip — the screw won’t hold.

Matching Rawl Plugs to Drill Bits

This is where accuracy matters.

Your drill bit should match the plug exactly:

• Red plug → 6mm drill bit

• Brown plug → 7mm drill bit

• Blue plug → 10mm drill bit

No guessing.

The plug should go in tight — you should need to tap it in, not push it in loosely.

Getting the Depth Right

Drilling too deep is a common mistake.

👉 Only drill as deep as the plug you’re using

Anything deeper:

• Adds no strength

• Increases risk of hitting pipes or cables

Simple tip:

Wrap a bit of tape around your drill bit to mark the depth. Once you hit the tape, stop.

Drill Technique (This Is Where People Go Wrong)

This part is often overlooked.

When drilling:

• Go straight in — don’t angle the drill

• Don’t wiggle the bit

• Let the drill do the work

👉 Wiggling the drill widens the hole — and ruins the fit

If you need a deeper hole, don’t force it.

Drill a bit, pull out, clear the dust, and go again. That keeps the hole clean and helps the drill cut properly.

Before You Drill — Check the Wall

This takes seconds but can save you a serious problem.

Use a detector (like a Bosch scanner) to check for:

• Electrical cables

• Water pipes

It’s not worth the risk of guessing.

Fitting the Plug Properly

Once your hole is drilled:

The plug should be tight.

Tap it in gently with a hammer.

If the lip sticks out slightly, use a spare screw and tap it flush so it sits level with the wall.

That way, whatever you’re fixing sits properly.

Screw Length — This Is Key

A lot of people get this wrong.

👉 Your screw should:

• Go through what you’re fixing

• Pass fully through the plug

• Stick out about 5mm beyond the plug

That’s what allows the plug to expand properly inside the wall.

Anything longer is pointless.

You won’t get extra grip from going deeper into brick or concrete — and you increase the risk of hitting something you shouldn’t.

What If You Mess the Hole Up?

It happens more than people admit.

You drill the hole, go to put the plug in… and it’s loose. No grip, no resistance — you already know it’s not going to hold.

Don’t try and force it or “make it work.” It won’t.

Fix it properly.

One option is to use a chemical anchor. Fill the hole, let it set (it dries quicker than you’d think), and then drill it again clean and to the correct size. That gives you a fresh fixing point like you never messed it up.

Another option is something like WetnFix. Wrap it around the plug, push it into the hole, and it hardens around it — tightening everything up and giving the plug something solid to grip.

These are worth keeping in your van or toolbox.

Because this sort of mistake happens more than it should — and having a quick fix saves time, avoids making bigger holes, and keeps the job tidy.

Fixing Small Screw Holes (4mm and Below)

If you’re working with a really small fixing — around 4mm — standard plugs aren’t always suitable.

They can be too big, or just overkill for the job.

There’s a simple trick that works well.

Drill your hole, then pack it tightly with wooden toothpicks or small bits of timber. Fill the hole properly, cut off the overhang, then drive your screw straight into that.

The wood compresses and expands inside the hole, giving the screw something to bite into.

👉 Done right, it holds surprisingly well for lighter fixings.

It’s one of those simple tricks that’s been around for years — and still works.

Final Thought

Fixing into brick and concrete isn’t about force.

It’s about accuracy.

• Right size drill bit

• Right depth hole

• Tight-fitting plug

• Clean technique

Get those right, and your fixings will be solid every time.

Rush it or guess it…

And you’ll be fixing it twice.s.