Signs Your Render Job Was Done Wrong

A quality render job should last well over a decade with minimal maintenance. If you're noticing problems within the first few years, or even the first few months, there's a good chance something went wrong with the application, not just normal wear and tear. Here are the key warning signs to look for, and what they usually mean.

Some very fine hairline cracking can be normal as a building settles, but visible cracks appearing within the first year or two, especially larger or spreading cracks, usually point to a problem. Common causes include render applied too thick in one coat, poor surface preparation, or the wrong render system used for the substrate. This is one of the most frequent issues we're called out to fix on homes across Miranda and Menai, usually on homes rendered a few years earlier by a different contractor.

If patches of render are lifting, bubbling or flaking away from the wall, it's a strong sign that moisture has gotten in behind the render, or the surface wasn't properly prepared before the render was applied. Render needs a clean, stable surface to bond to. Dust, old paint or contamination left on the wall during application can prevent proper adhesion, and the problem often only shows up once the wall has been through a full cycle of hot and wet weather.

Gently tapping rendered walls in a few spots is one of the simplest ways to check for a hidden problem. A solid, consistent sound means the render is well bonded. A hollow or drummy sound means it's separated from the wall behind it, even if the surface still looks fine. This kind of debonding often isn't visible until it's advanced enough to crack or fall away, which is why it's worth checking proactively rather than waiting for visible damage.

A render finish should be consistent across the whole wall, in colour, texture and sheen. Patchy areas, visible trowel marks, or noticeable colour variation usually point to inconsistent mixing, rushed application, or render applied in unsuitable weather conditions where parts of the wall cured differently to others. It's a cosmetic issue rather than a structural one, but it's still a clear sign of a rushed or careless job.

The trickiest parts of any render job are the details: corners, window reveals, and junctions with other materials like brick or cladding. Sloppy, uneven edges in these areas are often the clearest giveaway of a rushed job, since they take more time and skill to get right than a flat wall. If you're getting quotes and want to check a contractor's previous work, ask to see close-up photos of their corner and window detailing specifically, not just wide shots of finished walls.

Some efflorescence, the white, powdery salt deposits that can appear on render, is common, particularly on newer render as it cures. But if it's appearing heavily and repeatedly within the first year, it can indicate moisture problems behind the render or an issue with the render mix itself. This is worth investigating rather than just cleaning off repeatedly, since it tends to be a symptom rather than the actual problem.

If your render is showing any of these signs, the first step is getting it properly assessed before it gets worse or more expensive to fix. Depending on the cause, some issues can be patched, while others need sections of render removed and reapplied properly. If the work is recent, it's also worth checking whether it's covered under the original contractor's workmanship warranty. We regularly assess and repair render across the Sutherland Shire that was applied by other contractors, so if something doesn't look right, it's worth getting a second opinion. Have a look through our rendering services page or get in touch for a free assessment.

How soon should I be concerned about cracking in new render?

Fine hairline cracks can be normal, but visible or spreading cracks within the first one to two years usually indicate an application issue and are worth having assessed.

Can a badly rendered wall be fixed without redoing the whole thing?

Often, yes. Localised issues like small cracks or isolated bubbling can sometimes be patched. More widespread debonding or moisture issues usually need larger sections removed and reapplied properly.

Is efflorescence always a sign of a problem?

Not always. Light efflorescence on new render is common as it cures. Heavy or repeated staining is worth investigating further, as it can point to moisture getting behind the render.

What should I do if I suspect my render was done poorly?

Get it assessed by a different, licensed rendering contractor for an independent opinion, and check whether the original work is still covered by a workmanship warranty before arranging repairs.