How to repair rough wall patching above window?

Question

Hi team! Appreciate this forums existence, it's helped me as I fix our new home.

Previous homeowner did a bit of patchwork above the window. There was an air conditioning unit here which has been removed when ducted was put in and the hole repaired, but unlike the living room, this work (in the dining room) leaves a lot to be desired. Part of the patchwork is uneven, and it looks like they filled a large area.

I was thinking of either sanding (and/or chiseling given the amount) back the excess and filling it (then sanding again) to flatten the area out before we paint it in August.

I was also considering cutting the area out completely and replacing it with a new square of gyprock.

Which option is better long term? Is there an option 3 I am not aware of?

bendr · Answer

Thanks @MitchellMc

I've had asbestos checks done on most of the property (walls, interior, exterior) and we are in the clear fortunately!

Thanks for the suggestion for the gyprock topper product, I'll have a crack at sanding it back and smoothing it out. If the wall is lath, I imagine it would be quite damaged around that area due to the air conditional install and removal years ago. Hopefully I can bring it back to a good state!

MitchellMc · Answer

Given the age and character of your home @bendr, I'd be inclined to repair what's there rather than cut it out and replace it.

On a newer home, replacing a section of plasterboard could certainly be an option. However, there's a good chance your walls are actually lath and plaster rather than plasterboard. That's a traditional construction method where plaster is applied over thin timber strips, and cutting into it can quickly become a much bigger repair than you intended.

From your photos, the patch appears to be proud of the surrounding wall rather than badly cracked or failing. I'd start by sanding back the high spots. Once you've established a reasonably flat plane, apply a skim coat of

https://www.bunnings.com.au/gyprock-csr-2-25kg-less-mess-topping-compound_p0173348

over the entire repaired area, feathering it well into the surrounding wall. After it dries, sand it smooth and repeat with another light skim coat if needed.

One thing to keep in mind is the age of the home. There is a possibility that some wall linings or patching materials could contain asbestos. Before you start sanding, scraping or cutting into the wall, it's worth confirming what the substrate is. If you're unsure, having the material tested is the safest approach.

Once primed and painted, the skim coat repair should blend in nicely and leave the patch virtually invisible without disturbing the original wall.

Mitchell