How to stop water ingress in concrete block wall?

[andre999]

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.

[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]

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]

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]

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]

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]

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]

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

[andre999]

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 ?