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How to fix cement render cracks?

Hi everyone,

I have an old house and on the front stairs there are cracks in the cement render …I looks like they have been repaired in the past with some sort of semi flexible material…I wanted to know the best approach to fix the cracks …in some places they are around a centimeter wide and there is nothing behind the crack to push the filler into …it’s just empty so I couldn’t fill it with backer rod which I have used in the past.

Also there is one piece of render that has broken off the wall (see circle in picture) and I wanted to reattach it and fix the cracks around it…but not sure what to use to reattach it to the wall.

Grateful for any suggestions please!

Regards

Chris

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Comments

JacobZ

Hi @ChrisA,

The cracking pattern suggests the stairs are moving away from the house rather than just surface failure of the render. If you simply fill the cracks, they will almost certainly reopen.

The priority should be identifying why the steps are moving, for example, ground settlement, poor footing support, or water getting underneath. Once the movement is stopped, damaged render can be removed and re-rendered properly.

I'd suggest you contact a builder or structural professional to rectify the cause of the issue before any cosmetic repair is attempted.

If you were just going to carry out an aesthetic repair, you could use something like Sikaflex 11FC Purform to stick the render back in place, then seal up the gaps. An oversized gap filler rod pressed into the crack should still work because it is just there to hold the sealant in place while it dries. If you can wedge it in there before applying the sealant, it should stay there.

Allow me to tag @Nailbag and @Dave-1 to see what they think.

Jacob

ChrisA

https://www.workshop.bunnings.com.au/discussion/comment/61761#Comment_61761

Thanks for the info Jacob…so the sikaflex can be used to fill the cracks and stick the render piece back?
Also …can sikaflex fc be painted after it dries?

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/93358#Comment_93358

Hi @ChrisA,

That is correct, it is both a sealant and an adhesive, and yes, it can be painted over.

Again, this is not going to solve the underlying issue, and I would encourage you to speak with a builder about addressing it, but yes, it will cover the cracks and stick the render back in place.

Jacob

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/93358#Comment_93358

Good Evening @ChrisA

I have used that Sikaflex to seal my patio area and have painted over it. The paint hasnt peeled as yet (A couple of years)

I Would pretty much follow the suggested way that @JacobZ has laid out. And definently either keep an eye on the steps or see if there is a root cause for the issue and get a builder to come out and have a look (If they say redo then at least you have that long term to keep in mind and if they say its something else then you have saved some stress). A water leak or water running down the pillar in the same spot creating a damper area comes to mind as to why the steps could be pulling away from the house.

The inbetween time Sikaflex will work well 🙂

Dave

ChrisA

https://www.workshop.bunnings.com.au/discussion/comment/112938#Comment_112938

Thanks for the advice Dave…greatly appreciated…I will definitely monitor it closely…I have a building coming over soon for another job and will speak to him about this as well.

Thanks again!

Nailbag

Hi @ChrisA

Just also reinforcing the advice by @JacobZ in that I am a firm believer in fixing the cause before any cosmetic repair. It tends to put issues needing potentially urgent repair out of sight out of mind. Plus it's a double handling of both costs and time. And of course, not repairing the area cosmetically will have no impact on structural integrity.

I also agree that the issue is highly likely to be caused with an issue with the footings or the ground below as the entire sides are pulling away relatively evenly without evidence that we can see via the photos of any other cracking.

Speaking to a "registered" (far more qualified) builder will be the next course of action.

Nailbag

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