How to waterproof a crack in render along a tape line?

[JMcE]

We have a thin crack along the tape line in the exterior wall of our house where the brick work meets the concrete slab (see photos attached). This is fairly normal (so I'm told) as the house moves slightly over time and the tape line allows small cracks like this to occur without spreading through the entire render on the wall.
During a recent extreme rain event here in Queensland we had wind-driven rain penetrate through the wall, according to a builder the insurance company sent, this thin crack was the route of entry. We need to repair the crack or won't be covered by insurance for future water ingress.

We couldn't get a rendering company to take on the job were advised that we shouldn't attempt to sand back the crack or render over it as the tape line is doing it's job. The only option seems to be covering it with an elastomeric waterproof membrane.
To get this done professionally we were quoted nearly $7000.
Can we just do it ourselves? How difficult is this stuff to work with? Does the whole wall need to be repainted following the repair? Any thoughts or advice on whether this is something an average DIY person could handle (and save myself several thousand dollars) would be appreciated. Crack along tape line exterior wall Crack along tape line exterior wall Crack along tape line exterior wall

[JacobZ]

Hi @JMcE,

Thank you for your question.

Unfortunately, as your insurance company is involved, I think it is important that the work is carried out by a licensed professional so that you have some fallback if it fails. If you carry out the work yourself and it fails again, you are unlikely to have any recourse with your insurance company.

Hiring a professional to do the work will ensure the job is done in line with the relevant construction standards and you are covered in the event of its failure.

Allow me to tag @Dave-1 and @Nailbag for their thoughts on the job.

Jacob

[Dave-1]

Good afternoon @JMcE 

I am afraid I am repeating @JacobZ s words 😕 Better to be wise then let the insuarance company "have a reason" not to cover you down the track.

I would contact the insuarance company and ask "what is acceptable" to work being done on it and explain you are concerned about future insuarance issues. They hopefully will be able to narrow it down and then you can use the correct trade to install/fix the issue. 

I have not seen the tape issue before but then I have not worked on newer buildings. 

You could also check with your builders association goverment body for what is needed. (Big book of rules) I know there are elctrical ones, builder ones for sure. Just check against your state and country (Aus or NZ) Fair Trading NSW, National Construction Code but its a big bucket of worms to go through.

Dave

[Nailbag]

Hi @JMcE 

I'm confused as to why you need to rectify this at your cost if it's covered under building insurance. If it's not covered, why are they involved?

Nailbag

[JMcE]

Thanks Jacob (and others) for the responses. To clarify somewhat, the crack was identified by the building inspector the insurance company sent around after water got in. They covered the cost of replacing carpets this time but have said that it needs to be fixed or they won't cover future claims for water getting through in the same area.
The total cost of replacing carpets and drying out our rooms was in the region of $2000. We struggled to get any professional to take on this job and the only quote we got for remedial work was $7000 (they want to paint the entire house). At that rate, we would just let the water in and eat the cost of the replacing carpets again, and not make a claim at all.

I'm wondering if I can do something myself to ensure that we don't get water in during the next event and I don't have to get the insurance company involved at all. The process described by the painter who quoted seemed very simple, basically painting on some elastomeric paint.
I was wondering if someone has done this kind of thing before or if there are hidden pitfalls to look out for.  Failing that, I will just tape some plastic sheeting to the wall the next time we get a year's worth of rain in a week!

[Dave-1]

Good Evening @JMcE 

Thanks for the added info. It makes more sense now. I would be tempted to paint a waterproof material along that join. My only question is can that tape be removed or should it be paineted with a waterproof material The only waterproofing ive done was with a black tar like substance, it worked but its not what I would call a pretty solution. One of the other members may have an idea of the material to use tho.

Dave

[EricL]

Hello @JMcE 

As Jacob has mentioned in his response "If you carry out the work yourself and it fails again, you are unlikely to have any recourse with your insurance company." I propose trying to get another quote, but this time post it on Airtasker or Hipages. Make sure to put in as much information about the job so that the trades person looking at it can respond quickly to your inquiry. Just in case you were wondering what grey brushable waterproofing you can use, I suggest looking at the Crommelin 1L Exterior Grade Brushable Waterproofer - 1L.

If you need further assistance, please let us know.

Eric