How to fix bubble in render?

almondmagnum

A bubble came up in our render a few year ago but was fixed by our builder as was still within warranty. It has come up again, 5 yrs later but much smaller this time. I chipped off the big bits and there was no dampness underneath that I noticed.

House is 10 yrs old. It's brick under the render. Before fixing the render is there anything I can do to stop it happening again?

Thank you

MitchellMc

Welcome to the Bunnings Workshop community @almondmagnum . It's amazing to have you join us and many thanks for your question on repairing render.

The main thing to check is what the surface underneath is like now that you’ve chipped away the loose render. Is it still solid, or does it feel powdery and crumbly?

If it’s powdery or breaking down, that usually means the render hasn’t bonded well to the surface. In that case, any patch repair you do may only be temporary, as the surrounding material could continue to fail over time. The only long-term fix there is to remove all the compromised render back to a solid surface and reapply.

If the area feels firm and well bonded, you should be fine to patch it. Lightly misting the area with water before applying your repair mortar can help improve adhesion and reduce the chance of it drying too quickly.

From what you’ve described, it doesn’t sound like moisture is the main issue, which is good. It’s more likely just some localised breakdown of the render over time.

If you can, it might be worth keeping an eye on nearby areas as well, just in case there are other weak spots starting to form.

Here's a helpful guide: How to repair a rendered wall.

Please let me know if you have any questions.

Mitchell