How to fix mouldy ceiling?

Question

Hi,

I have lately noticed the ceiling getting mouldy, under evaporating system (leaks from roof, RACV guy fixed the leak)

Do you think i can just clean it off with any mould remover and re-paint or should i get the ceiling panel replaced?

it seems the ceiling is still wet.

Please advise

JacobZ · Answer

Hi @hajunu,

Are you confident that the leak has stopped? Does the plasterboard still feel wet?

Unfortunately, that looks like plasterboard that has softened due to water damage. That kind of bubbling shouldn't happen if the plasterboard is still in good condition.

Best case scenario, you could give it a sand with a sanding sponge to smooth out the surface, then prime and paint. From what I can see though, that section of plasterboard is probably too far gone for this to be effective. If you try sanding wet plasterboard, it will tear and will never quite look right. You could try giving it a sand and then upload a photo so we can have another look, but I suspect that plasterboard is going to have to get cut out and replaced.

Have a look at

https://www.bunnings.com.au/diy-advice/diy-skills/repairing/how-to-repair-a-large-hole-in-plasterboard

. This technique is what I would recommend if the plasterboard is not salvageable.

Let us know what you find. I will assist further when you have the chance to get back to us.

Jacob

hajunu · Answer

Hi @JacobZ

I applied the mould action to remove the mould, followed by wiping after 24 hrs.

Since then i left for a while, then i just noticed that there is blistering.

How should i remove and/or what do i need to do any action before painting?

JacobZ · Answer

Hi @hajunu,

Generally, over the course of three weeks you would expect a small wet patch to dry out naturally. If it is still wet, then I'd question whether the leak has definitely been fixed or not.

I'd suggest you double check that there is not an ongoing leak before you proceed with any repairs as if it is ongoing, then the mould will return.

If you have confirmed there is no leak and the plasterboard still feels wet, you want to maximise the amount of air running over the plasterboard. This can be done by opening windows to allow natural airflow and using fans or blowers.

I'd also check whether there is insulation on top of the ceiling sheet. If there was a leak that has wet your ceiling insulation, it will need to be taken off that area to help it dry, then likely replaced as it would almost certainly be growing mould.

Let me know if you have any further questions.

Jacob