Better long-term fix for cracks?

We live in a beautiful heritage home in Adelaide with traditional plaster walls — full of charm, but also not without their quirks. In a previous older property, we dealt with wall cracks once, patched them properly, and they stayed put for years. But this time, it's been a very different experience.

Just six months ago, we invested over $XX,XXX to repaint the entire house and repair visible cracks throughout the property. The painters used a standard filler and sanding method, similar to what had worked well in our last home. But now, barely half a year later, the cracks are already reappearing. Understandably, it’s been quite disappointing.

We’ve had a structural engineer assess the property. Thankfully, there are no foundation issues or ongoing water problems.

We’ve had a structural engineer assess the building and confirmed there are no foundation issues or drainage problems. So, we're left asking:

Will using a patch with fibreglass mesh/tape improve longevity?
Should we remove part of the plaster and fix the bricks behind it?
What is the best filler for flexibility?

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Comments

EricL

Hello @Michelle_Adl

I feel that this will be an ongoing issue with your walls as I suspect that the plasterboard wall is anchored to a timber frame. The moisture being released by the brick wall is affecting the timber frame and makes it move and naturally this movement translates to the plaster wall creating the cracks that you now see. Adding the mesh tape might help, but the crack will automatically transfer to the weakest part of your plaster wall. For long term repair, I suggest having that whole section of the plaster board wall removed and the timber frame upgraded to hardwood or steel for better dimensional stability.

The hardwood will be able to better resist the moisture in the wall and will not move as much when compared to standard timber, the steel of course will not move at all.

Let me tag @Dave-1 and @Nailbag for their recommendation.

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

Eric

Nailbag

Hi @Michelle_Adl

The cracks don't appear to be a result of failing fillers, but they are very substantial. Since you have already ticked off the engineering issue boxes, I think it might be worth getting professional advice on a period home restoration company. or possibly a leak detection service. Not that I think you have leaks, but maybe there is some form of long term moisture causing the cracks?

Nailbag

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/53506#Comment_53506

Morning @Michelle_Adl

I was thinking along a join failing but then through the rest of the pics you can see the randomness plus expected points of cracking to occur, I am wondering what the makeup of the plaster is, whether its old horsehair or a more modern type of plaster? If it dosnt effect the herritage listing of the house I would be tempted to redo the wall the plaster cracking is on (one to start with) and determin in the process what the cause may be of the cracking. Or as @Nailbag has suggested, a proffesional plasterer, not just a painter may be able to help out with the reasons.

Dave

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