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How to stop water ingress in concrete block wall?

First post here.

I have a bedroom interior wall showing marks of water ingress. No issue from the ground as the unit is on 1st floor. The unit was built in the late 60'. Please see attached images.The red line boundary marks the exterior wall of the affected bedroom wallAffected interior bedroom wall

Early this year, the exterior wall was painted with zinsser watertite. It helped to block water ingress on most part of the wall but there were some small marks appearing on the wall after a rainy day.

I have read that there are better solution to fix the water ingress.
Do the cemix's aquastop and no-damp-waterproofing or sika's ready mixed admixture watertight or any other product that can fix the water ingress on concrete block?
Appreciate your suggestions.
Thank you.

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Comments

JacobZ

Hi @andre999,

A warm welcome to the Bunnings Workshop community and thank you for your post.

I suspect the issue is not from water coming through the wall, but from condensation appearing on the inside of the wall due to the disparity in temperature between the inside and outside of the wall. Double brick walls eliminate this issue by having an air gap between the exterior bricks and the internal bricks for the different temperatures to dissipate, but single-layer block walls do not have this gap.

Unfortunately, applying a waterproofing material to the wall will not stop this from happening as the moisture is not coming from outside, it is condensing on the wall when the warmer air from the room hits the colder bricks.

The solution to this issue is insulation on the internal wall. Check out Foilboard Commercial Brick Wall or Concrete Wall Insulation as an example of how this can be done. Foilboard is an insulation product covered with aluminium foil that acts as a water-resistant membrane.

Following the guide on Foilboard's website, you can use furring channel clips to attach furring channels to the wall. You can then attach plasterboard to the furring channel to cover everything and give the room a finished look.

This is a good solution that will stop the condensation issue without losing much space in your room.

Allow me to tag @Nailbag, @Dave-1 and @TedBear for their thoughts.

Let me know if you have any further questions.

Jacob

Note for our New Zealand readers: The use of foil insulation products has been banned in New Zealand. A modified method using insulation batts is still possible.

Nailbag

Hi @andre999

Unless this wall, is sub-ground level, then it sounds like @JacobZ is on the money with both the cause and solution.

Nailbag

andre999

https://www.workshop.bunnings.com.au/discussion/comment/45531#Comment_45531

Thanks for your suggestion JacobZ. I'm still not convinced though.

Sorry, I should add that I have another master room in the front with the wall on the same side but with no issue with the mark of condensation or water ingress.

There was a bit of history with this flat's affected bedroom. There was no condensation/water ingress issue with the affected bedroom's wall few years back. Due to the flashing replacement, the exterior paint was exposed and peeled off the exterior wall after the flashing work. That was when the marks of the water ingress started. Soon after I had the wall painted with zissler watertite.

I was wondering if I should go for rubber paint on the wall/

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/84883#Comment_84883

Hi @andre999,

Thank you for the extra details, they certainly help.

I trust your judgement on the situation as you are working with the full picture, but it's unlikely that water will pass through the block wall unless there are obvious gaps in the paint, or it can find a way to sit on top of the block wall.

I fear that if you paint the block wall with rubber membrane paint, you will spend money to find it hasn't really fixed the underlying issue, so I'd like to do some further investigation before we come up with a plan.

As you are confident that condensation is not the issue, I suspect the issue lies elsewhere.

Does the issue only occur during rain events? Are the watermarks inside predominantly at the top of the wall?

Considering the history you've mentioned, the issue may be coming from the new flashing. If water can find a way underneath the flashing, it could certainly find its way inside.

It looks like the flashing may have a mitred corner at the far end of your first photo. If the corner of the flashing wasn't well sealed, water could find a way under it and in turn track down the wall. Is it possible to get a photo of this?

Once you've gotten back to me, I'll be happy to assist further.

Let me know what you think.

Jacob

TedBear

https://www.workshop.bunnings.com.au/discussion/comment/84883#Comment_84883

Hi @andre999

I agree with @JacobZ that it may be a flashing issue.

It seems unlikely that this much water is coming through a vertical wall surface after you've already sealed it.

It is interesting that in some spots where the water is leaking through, there are brown stain marks. I am wondering if this is from water which has been running down and through timber and into the bricks. There are no such marks on the outside, so the water is likely to be getting into the bricks from above.

Since it is a single block wall there are no metal ties that would account for the brown stains.

This part of the wall appears to be at the lower part of the roof slope, so perhaps the water ingress is starting from the higher end of the wall and running along the top of the blocks before saturation and leak through is occurring up there ??

What is the roofing material? If it is steel, is there a possibility that the flashing is too tight and pulling the edge of the steel down, or that there is a leaky join somewhere?

(Without seeing the situation we can only offer guesses at options to check for of course.)

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/107540#Comment_107540

Afternoon @andre999

My first thought was a waterleak from above, running down the inside of the bessa blocks that may have been filled with soil.

When I read @JacobZ suggestion it does make a lot of sense.

After reading that the flashing has been replaced and now the issue has risen im banking oin somewhere along the flashing there is a point where water is getting to drip into the cavity of the bessa blocks, seeping down through whatever fill they may have used and coming through to the interior as the exteriour is "stopped" with your new paint work.

You could check with a heat temperture gun when it rains to see what the walls temperture is and that may give an indication of how the water is getting to that point. Im thinking the blockwork will be cooler where there is water seeping.

Dave

andre999

https://www.workshop.bunnings.com.au/discussion/comment/107535#Comment_107535

Hi @JacobZ

I notice the issue occur during rain events. Yes, I would say the watermarks are predominantly near the top of the wall.

I trust the builder did a good job to secure the flashing from any leak. Please find attached photo for the flashing work. Do you think I should get another builder to verify there is no leak from the flashing?

flashing to bottom endflashing from top endbefore work

Here are the photos of the far end from the ground.

Thank you @JacobZ

andre999

https://www.workshop.bunnings.com.au/discussion/comment/107540#Comment_107540

@TedBear Thank for your questions. I hope with the attached photos, it may answer your questions.

andre999

https://www.workshop.bunnings.com.au/discussion/comment/121022#Comment_121022

Thanks @Dave-1 for your help and suggestion. I have attached a few photos of the flashing work done by a builder. Do you think that getting another builder to check if the water still leak ?

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/121022#Comment_121022

Hi @andre999,

It's certainly worth having it checked as everything you've said about when it happens and the location of the water ingress points to it coming from above.

I don't see a need to engage a different builder. The reality with waterproofing works like this is that sometimes you can do everything right and water still finds a way in where you hadn't expected. The work your builder has done looks good, but they can't predict the future.

I'd give the original installer a call and let them know what is happening. Hopefully, they are reasonable and will come out to have a look.

Let me know what you think.

Jacob

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/129407#Comment_129407

Morning @andre999

I would give the original builder a call and explain whats happening, as @JacobZ has suggested even when things are done right sometimes water will still find another way in.

Dave

andre999

https://www.workshop.bunnings.com.au/discussion/comment/129407#Comment_129407

Hi @JacobZ

Thanks for your reply. I have raised this matter to the original builder. The builder mentioned the flashing should not be the cause of the leak after he had done the water proofing. Instead he suggested to get an waterproof engineer for better suggestion.

Thanks.

andre999

https://www.workshop.bunnings.com.au/discussion/comment/134714#Comment_134714

Thanks @Dave-1 I have replied to Jacob that the builder suggested to have a waterproof engineer to have a look.

TedBear

https://www.workshop.bunnings.com.au/discussion/comment/134715#Comment_134715

Hi @andre999 , seeing the photos has made me curious... the black material appears to be going under the flashing, which would mean that any water that gets onto it will also go under the flashing, going to ?? instead of being directed onto the flashing where it would run away safely.

Have you tried putting a hose onto the roof and seeing how the water runs?

andre999

https://www.workshop.bunnings.com.au/discussion/comment/138165#Comment_138165

Hi @TedBear Thanks for your question. I think the black material is a paper material as water proof to block water coming into the flashing. The flat is on 1st floor and I am not a typical DIYer, so I don't have the equipment to go up the roof.

@JacobZ @Dave-1 I have gotten a builder to inspect the flashing and he said there is no water visible underneath the flashing after rain events recently. He mentioned about gutter that may overflow when it is rainy day and also the roof angle is almost flat.
Do you think it is likely the overflowed water from gutter flows back via underneath roof to the block wall ?

I guess I will have to wait for the rain event to witness it.
red line marks the gutter

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/140472#Comment_140472

Morning @andre999

Mmmmm Yes the water could curl under and backwards especilly if its windy and driven rain. The Bubbling effect on the blocks inside looks like a long term issue. I am starting to think that maybe you should sand the "bubbles" back to the bessa block itself and see if they feel wet in the days after rain. If they do then you know water is coming from somewhere. A temperture gun would be handy to check the temperture of the area during rain and after rain events.

With the roof angle being almost flat it definently makes it easier for waterto find its way under sealed edges.

Dave

EricL

https://www.workshop.bunnings.com.au/discussion/comment/140472#Comment_140472

Hello @andre999

I propose engaging the services of a leak detection specialist. Specifically, the one that offers thermal imaging. Using the thermal imager you 'll be able to see where exactly the water is entering from and where it is sitting in your wall. By finding the exact point of failure you'll be able to repair this leak that is causing damage to your wall.

If you need further assistance, please let us know.

Eric

andre999

https://www.workshop.bunnings.com.au/discussion/comment/142170#Comment_142170

@EricL Thank you for your suggestion.

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