How to patch uneven walls and prepare for re-painting?

Question

Hello, I'm brand new to DIYing and home maintenance/reno, and may have made a huge mistake(s).

1. There is a wall that's quite bumpy. The intention is to sand it down and repaint. When scraping off old paint, I ended up taking out chunks of plaster, and exposing this grey/brown material at the back. Not sure if it's mould (my main worry), or it's just base layer (as a friend suggested).

To fix the wall, can I just use filler to plug the hole & mesh to cover, and then filler on top? I'm referencing the Bunnings guide. Or do I need different material? I've contacted a mould remediation person but still waiting for them to get back.

Since I've also taken off a bit of the ?sealant/caulk at the wall/doorframe joint, should I just add more sealant into the hole or must I remove all the old sealant and re-caulk. What type of compound should I use?

2. I started with just scraping flaking paint at the skirting in one of the rooms, but then larger pieces of paint got lifted by the scraper and it was SO easy to just peel off these sections with scraper or even my fingers. So I kept peeling and have all this exposed ?plaster. Now I'm wondering if I should stop the urge to peel and just plaster & feather the edges, and then prep the wall for painting OR I continue peeling the paint entirely (less plaster & feathering needed?). Someone said the plaster was probably not primed properly the last time the wall was painted, hence the paint coming off so easily.

Materials I already have:

* Nordsjo Professional 330g Rapid Repair Filler
* Selleys 300g White Wet Area Waterproof Silicone Sealant
* Parfix 1kg Ready To Use Multipurpose Filler
* Parfix 450g White Gap Filler

Everything seems so overwhelming at this point, like I've made things even worse than before. I honestly have no idea what I'm doing. Would appreciate any feedback and recommendations on what to do.

Thanks!

EricL · Answer

Hello @blursquid (Abigail)

My apologies, I was under the impression that you were working on a plasterboard wall. But it appears to be a masonry wall. Looking at your photo of the holey wall, it appears to be white set render and not just paint. If the sections that have come off are quite large it might be necessary to render those sections again. I propose knocking on your wall to determine if it is masonry or plasterboard. Plasterboard will give you a hollow sound and of course masonry will be like cement, hard and solid.

In regards to the asbestos, I propose doing a bit of an investigation and finding out if the strata had any asbestos testing done. You can also follow up the former owners to see if they had any independent testing done as well just to be on the safe side.

Just to help out with the white plaster rendering, here is a handy guide to give you an idea of what it looks like - How To White Set Internal Render.

Please stay safe and make sure to find out if any asbestos testing was done in the apartment before you continue.

If you need further assistance, please let us know.

Eric

blursquid · Answer

Hi @EricL , Thanks for your response! I completely forgot about asbestos. This apartment (1980) was renovated by the previous owners before I bought it (kitchen, bathroom, toilet) - do you think the fact it got renovated might mean there's no asbestos? I was under the impression that any works could only be done after an asbestos test & removal.

The shower went from this to this

to this

. The holey wall

is on the back of the shower as you can see in this photo:

. I was told there was a leak during renos but "its all fixed and good now".

I will double check with the strata if they have had any asbestos testing carried out (also assumed this was a requirement for old apartments, no interior asbestos was mentioned in the AGM).

*I will start wearing PPE, im bad at remembering that.

Many many thanks,

Abigail

EricL · Answer

Hello @blursquid

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your wall revamping project.

I propose pausing for a moment and having a quick safety check. Before going further into your wall panels, it’s important to consider the age of your home. If it was built before 1995, the wall panels may contain asbestos. Drilling, cutting or sanding into asbestos-containing material can release hazardous fibres. If you're unsure of the age or whether the material contains asbestos, it’s best to have it tested or consult a licensed asbestos professional before proceeding. You can arrange testing through a licensed asbestos assessor or testing service. If there is any doubt, avoid disturbing them at all.

If the test is positive, you'll need to engage the services of an asbestos removal specialist. But if the test is negative then you can continue with your repair project.

On the condition that the test was negative, below is our suggestion on how to repair the wall.

When chunks of plaster come away and you see a grey or brown material underneath, it’s usually just the base layer of plaster or the paper face of plasterboard rather than mould. It often looks dull, patchy, or slightly fibrous which can be worrying, but mould normally appears spotty, powdery, or damp and often has a musty smell. If the surface you exposed is dry and fairly uniform, it’s almost certainly just the substrate and perfectly safe to repair over.

To fix the damaged areas, you can absolutely fill them and smooth the surface again. What you already have will work well, especially your Nordsjo Professional 330g Rapid Repair Filler for deeper spots and the Parfix 1kg Ready To Use Multipurpose Filler for finishing and feathering. If a hole is a bit deeper, just apply the filler in two thin layers rather than trying to do it all at once. Mesh is only really needed if there is a crack or a larger section missing, otherwise you can simply fill, let it dry, sand smooth, and then prime before painting. Priming is important here because exposed plaster absorbs paint differently and skipping this step can lead to patchy or peeling paint later.

With the paint that’s peeling off easily near the skirting, you’re also on the right track. This usually happens when the wall wasn’t properly primed before the last paint job, so the paint is only loosely stuck and lifts off very easily. It’s best to remove anything that comes off without force, but stop once you reach paint that feels firmly attached. There’s no need to strip everything back, and doing so can actually create more repair work. Once the loose edges are scraped, lightly sand the transition so it blends smoothly, skim any low spots with filler, then prime the whole area before repainting. That will lock everything down and give you a consistent finish.

For the wall to doorframe joint, since you’ve already disturbed the sealant, you don’t need to remove everything unless it’s loose. Just cut away anything that’s lifting and apply a fresh bead. Your Parfix 450g White Gap Filler is the better choice here because it’s paintable and designed for wall and trim joints. The Selleys 300g White Wet Area Waterproof Silicone Sealant is better suited to bathrooms and kitchens and can’t be painted, so it would make finishing the wall harder.

Overall, you’ve actually done the hardest part already by removing the loose paint and exposing the problem areas. From here it’s just filling, smoothing, priming, and repainting. It can definitely feel overwhelming when the wall suddenly looks worse than when you started, but this is a very normal stage in DIY repairs and you’re absolutely heading in the right direction.

Here are some handy step-by-step guides:

* How to patch a plaster wall 
* How To Fix Cracks In Plaster Walls 
* How To Paint A Wall Or Room: Step-By-Step Guide 
* How To Silicone Seal A Bath (the techniques used are applicable to your project)

Please remember to wear personal protection such as gloves, goggles and a mask when working on your project.

If you have any other questions we can help with, please let us know.

Eric