Why Perth Render Fails

When the render is failing, unfortunately, a fresh coat of paint won’t magically restore it.

My name is Ben from Perth City Painters, and I was standing on a ladder in City Beach last Tuesday and pulled a piece of render off a wall that was as soft as a digestive biscuit.

The homeowner thought they just needed a quick coat of paint to cover some flaking but the reality goes deeper than that.

The render wasn’t just peeling. It was blowing off the wall because the salty air had spent a decade eating the brickwork from the inside out.

Applying a fresh topcoat to walls in this condition is essentially bogging up a problem that will reappear before the next summer.

If your render is failing, paint is just a temporary bandage on a structural wound.

Why your walls sound hollow when you tap them

Most people notice a bubble in their paint and assume the product has failed. In our experience across the Western Suburbs, the issue is almost always the bond between the plaster and the brick.

We call this a drummy render. You can find it yourself by walking along your perimeter walls and tapping the surface with your knuckles.

If it sounds like a hollow drum, the render has de-bonded.  And because this has happened there is now a physical gap between the wall and the coating, moisture gets trapped in the space and turns into a pressure cooker when the Perth sun comes out.

The Fremantle Doctor

Living near the coast is a luxury but the Fremantle Doctor brings more than just a cool breeze. Every afternoon when that breeze comes through it leaves behind a fresh layer of salt.

This salt gets into the pores of the render and undergoes a process called efflorescence where mineral deposits expand as they dry.

These crystals are strong enough to snap the internal bonds of the cement.

Spotting the Rot

• Tap your walls, if there is a hollow sound that means the render has already detached.
• Look for the fur, if there is white powder that means salt actively is destroying your masonry.
• Watch the cracks, vertical splits are the main entry point for water.
• Check the base, if the bottom of your wall is crumbly, you have rising damp.

Most painting quotes are a trap

We see it all the time in Subiaco and Nedlands, where a homeowner gets a cheap quote that sounds great. But most of the time you get what you pay for. If your quote has no inclusion of substrate restoration, that means a fresh coat of paint over the problem, not fixing the problem.

A cheap contractor will just paint over the dirt and salt. They might bog up a few cracks with interior filler but that filler is rigid and will snap the first time the house moves.

We use elastomeric membranes for a reason. These coatings act like a rubber skin, stretching when the wall expands in 40 degree heat and shrinking when it cools down at night.

Without that flexibility your new paint job will be flashing. Flashing means you can see every single patch and repair through the finish.

The screed test and real restoration

True restoration starts with a grinder, not a brush. We have to grind back the failing render to reveal a fresh surface for the paint to bond to.

When we worked on a project in Dalkeith recently, we ended up stripping forty percent of the south facing wall. The render was so sandy it wouldn’t hold a primer.

Once the loose sand render is gone, we decontaminate the wall. We use commercial high pressure cleaners to strip away the salt crust and the old, chalky paint residue.

If you skip the wash, you are painting onto dust. It doesn’t matter how expensive the paint is. If you surface is dirty and sandy, the paint won’t stick.

Thermal shock

It seems to be a rising trend in Perth for dark charcoals and deep greys. While it looks modern it also puts stress on your render.

Dark colours soak up the sun and get incredibly hot. This leads to thermal shock where the render expands so quickly it actually cracks under the pressure.

This is why in most cases we recommend using solar reflective coatings for these darker colours.

These types of paint reflect the infrared spectrum which means it will keep your walls cooler and prevent cracks.

This extra small detail can help save future maintenance.

Why a registration number matters

Perth City Painters is a Registered Painting Contractor (Reg #7821). This isn’t just a number, it means we are qualified to diagnose these substrate failures.

An unregistered painter can be anyone who goes to Bunnings and buys a paintbrush and some paint. There is a vast difference between someone with technical expertise and someone who can paint well.

We provide a ten year workmanship guarantee because we know our prep work is bulletproof.

Cutting corners on an exterior repaint is the most expensive way to save money. You will eventually have to pay someone like us to strip it all off and start again from the bricks up.

Is your render actually solid?

If you are concerned with the state of your exterior already don’t wait until winter hits. The next big storm will find the leaks for you and by then the water is already into your timber frames or internal plaster.

We can come out and do a proper test and moisture analysis on your walls. We can honestly tell you if your walls need a full restoration or just a refresh.

Let us help you get your render back on track.

Get in contact with us today!