How to Fix Ceiling Cracks Properly (And Stop Them Coming Back)

How to Fix Ceiling Cracks Properly (And Stop Them Coming Back)

Ceiling cracks have a habit of coming back.

You fill them…

Paint them…

Think they’re gone…

Then a few months later—

👉 There they are again.

That usually happens because the crack was covered…

Not repaired.

And ceiling cracks need repairing slightly differently to wall cracks.

This is how to fix them properly.

First — Find Out What Kind of Crack It Is

Not every ceiling crack needs the same repair.

Fine hairline cracks along plasterboard joints are often movement cracks at board seams.

Very common.

Especially in older houses where joists flex slightly when people walk upstairs.

But if the crack is wider, uneven, or the ceiling boards feel loose—

You may have movement in the plasterboard itself.

And that needs dealing with first.

If The Ceiling Board Is Loose — Fix That First

Very important.

If the plasterboard has lifted, moved, or feels uneven—

👉 Screw it back first.

Don’t skip this.

No filler or tape will hold properly if the board itself is moving.

Use suitable plasterboard screws and pull the board back firm before repairing the crack.

Fix the movement first.

Then repair the crack.

Step 1 — Rack The Crack Out

Don’t skim over a hairline crack.

Open it up.

Rack it out as deep as it will go.

Then feather the edges slightly with a scraper so the repair blends back properly.

This gives your filler something to bond to.

Step 2 — Clean Out The Crack

Brush out all dust.

Ideally blow it out as well.

Dust inside a crack weakens adhesion.

👉 Clean crack. Strong repair.

Simple.

If the area is dusty or porous, sealing with Zinsser Gardz before filling is a good move too.

Step 3 — Wide Gaps Need Filling First

This is where many people go wrong.

If the crack is wide—

Don’t scrim tape over an open gap straight away.

It can cause the tape to bubble.

And ruin the repair.

Do this instead:

Fill the gap first.

Use filler mixed thick, not runny and fill the crack level.

Leave it to dry.

Then sand it flush.

Only after that—

Apply your scrim tape.

👉 Fill first. Dry. Sand. Then tape.

That order matters.

Step 4 — Use Plasterboard Scrim Tape

For ceiling cracks, use plasterboard scrim tape.

(Not standard fibre tape.)

Bed the scrim into a skim of filler.

Press it in properly so it’s embedded.

Not sitting proud.

Then skim over it.

Let that dry.

Go over it again with another pass of filler—

Slightly wider—

And feather it out.

That layered repair is what stops the crack telegraphing back through. make sure you have enough filler covering the tape as if it thedges show you will not be able to hide them after easily.

Step 5 — Use The Right Filler

For movement-prone cracks, I’ve had good results with Toupret Flexfill inside the crack itself.

If using it—

Keep it in the crack only.

Don’t spread it out as a finish coat.

It’s strong—

But not pleasant to sand! near impossible!

Use a finish filler over the top for your skim coats.

I’ve had good results with Toupret Skim Filler for that. Decent suction, and easy to sand.

Step 6 — Sand and Feather The Repair

Once dry—

Sand it smooth. use a sanding machine here to get a uniform seemless finish. its difficult by hand sanding a ceiling.

Feather the edges into the surrounding ceiling.

Take your time here.

A rushed sand shows after paint.

And try sanding with a block rather than loose paper in your hand—

It helps keep repairs flatter. Use 80 grit, then feather it down to 120 grit then 240 grit sandpaper

Step 7 — Prime Before Painting

Don’t skip this.

Some fillers can flash or grin through paint.

Prime the repair first.

Especially on ceilings where side-light can show every patch.

Zinsser Gardz or a suitable primer/undercoat works well.

Then paint.

The Repair Sequence That Works

Simple order:

✔ Screw loose plasterboard back first (if needed)✔ Rack out crack✔ Clean and seal✔ Fill wider gaps first and let dry✔ Sand flush✔ Apply plasterboard scrim tape✔ Skim over and feather out✔ Sand✔ Prime✔ Paint

That’s the system.

And it works.

What Causes Ceiling Cracks In The First Place?

Usually one of these:

• Movement at plasterboard joints

• Joist flex in older homes

• Loose ceiling boards

• Settlement movement

• Poor original taping

• Moisture movement

The crack is the symptom.

Movement is the cause.

When To Call A Professional

If the crack:

• Keeps reopening

• Is widening

• Comes with sagging

• Runs across ceiling and down walls

• Appears with water staining

👉 Get it assessed.

Because that may be more than a plaster crack.

🔚 Final Thought

Most recurring ceiling cracks aren’t a filler problem.

They’re a repair method problem.

Open it up.

Stabilise it.

Tape it properly.

Feather it out.

Prime it.

And you fix it once.

❓FAQ: How to Fix Ceiling Cracks

What is the best way to repair a ceiling crack?

For recurring cracks, rake it out, fill if needed, reinforce with plasterboard scrim tape, skim over and feather out.

Should I tape a ceiling crack before filling it?

If the crack is wide, fill it first and let it dry.

Tape straight over a deep gap and it can bubble.

Can I use scrim tape on ceiling cracks?

Yes — plasterboard scrim tape is ideal for many ceiling seam cracks.

Why does my ceiling crack keep coming back?

Usually movement, loose board fixing, or the crack wasn’t reinforced.

Should I screw loose ceiling plasterboard first?

Yes.

Always fix loose board movement before repairing the crack. Use plaster board screws.

Very important.

What filler is best for ceiling cracks?

A flexible crack filler inside the crack is wide, toupret flexfill. Plus a finish skim filler Toupret skim and patch over scrim tape works well.

Should I prime a ceiling crack repair before painting?

Yes — especially to stop flashing and visible patching. use zinseer Guardz