Bubbling Paint & Blown Plaster

Rising damp symptoms · Inner West

Bubbling Paint & Blown Plaster

When paint blisters and plaster crumbles away low on a wall, salt and moisture are usually working behind the surface. Here’s what’s really going on.

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What it means

Why your paint won’t stay put

Paint needs a dry, stable surface to bond to. When rising damp carries moisture and hygroscopic salts into the plaster, the surface can no longer hold a finish — paint blisters, bubbles and peels, and the render behind it becomes soft, powdery and “blown.” You’ll often find fallen flakes of paint and plaster gathered along the skirting. Because the salts keep drawing moisture from the air, simply scraping and repainting fails within months. This symptom usually travels with a tide mark and white salt efflorescence, and if it’s left long enough, mould low on the walls.

Watch it happen

Why the plaster blows — and how we fix it

Hit play. Watch moisture and salt rise into the plaster zone that blisters your paint, then see a new damp course cut it off so fresh plaster can hold.

GroundwaterInsideTide markNew damp course

The wall starts dry

Press play to watch how ground moisture climbs a solid brick wall — and exactly what a new damp course changes.

—Wall base moisture
—Salt / plaster damage
DryRising damp
Why it happens

What’s breaking down the surface

Blistering paint and blown plaster are surface symptoms of moisture and salt inside the wall — not a painting problem.

Salt in the plaster
Rising moisture deposits salts that expand and push the finish off.
Blown render
Trapped moisture
Modern plastic paints stop the wall breathing, so damp lifts them.
Blistering
No damp course
With nothing blocking the ground moisture, it keeps re-wetting.
Recurring
Sound familiar?

Signs of damp-driven paint failure

If two or three of these ring true, the cause is behind the paint, not the paint itself.

Blistering & bubbling

Paint lifting into bubbles low on the wall.

Powdery, soft render

Plaster that crumbles or feels chalky when touched.

Flakes on the floor

Paint and plaster gathering along the skirting board.

Worst near the base

Damage concentrated in the lower metre of the wall.

Comes back after repainting

Fresh paint failing again within months.

Musty edges

A damp smell around the affected patch.

★★★★★

Rated 5.0 from 108 Google reviews

What Inner West homeowners say about our damp & ventilation work.

★★★★★

“Inner West Rising Damp treated rising damp affecting several lower walls in our Croydon property and everything was handled professionally.”

J
Jack HopmanCroydon · Google review
★★★★★

“Mould problems in one bedroom completely disappeared after the works were completed.”

S
Sam O’MearaGoogle review
★★★★★

“The house constantly felt humid downstairs before the ventilation work was done.”

M
Max KrefftGoogle review
Which fix do you need?

Two problems, two solutions

Blown plaster is a wall-moisture problem — here’s how to be sure which fix you need.

Moisture in the walls

Rising damp treatment

If moisture is wicking up through the walls — tide marks, salt, bubbling plaster — you need a new damp course, not just airflow. We diagnose and install it.

Rising damp treatment →
Moisture under the floor

Subfloor ventilation

If the damp air is trapped under the house — musty floors, mould, condensation — you need ventilation to move it out and keep the space dry.

Subfloor ventilation →
Good questions

Bubbling paint FAQs

Why does the paint bubble again after I redo it?
Because the moisture and salt are still in the wall. Until the source is treated and the salt-damaged plaster replaced with a salt-resistant system, any new paint sits on an unstable surface and fails again.
Do you replaster as part of the job?
Yes. We hack off the blown, salt-contaminated render and re-plaster with a salt-resistant system once the damp course is in, so the finished wall is ready to repaint.
Could it be condensation instead of rising damp?
It can be. Condensation tends to affect cold spots and upper areas, while rising-damp paint failure clusters in the lower metre of ground-floor walls. We confirm which on-site.
How long before I can repaint?
The new plaster needs to cure and the wall to dry. We’ll advise the right timeframe for your specific wall at the inspection.
Free, no-obligation

Paint won’t stay on the wall? Let’s find out why

We’ll check whether rising damp is behind it, treat the source and make good the plaster — starting with a free, fixed quote.

Call 02 9158 9921

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