Roof Leaks - HELP

[vbplease]

No, imo the white residue is a separate issue to the waterproofing.

As you say the white residue is blocking up the drainage points - perhaps the drains have been blocked for a long time, this has caused ponding on the roof resulting in the calcium residue? It's definitely not concrete cancer - which is corrosion of the reinforcement. The plumber has no idea what he's talking about if he told you that.

How big is the roof area? How much of it do you know has inadequate waterproofing?

I'm not sure if you said this earlier, but how old is the building? If it's less than 6yrs old then your strata should be chasing up the original builder.

 

[vbplease]

Second thoughts - the white residue could be mineral salts leeching from the mortar. Definitely not concrete cancer though.

 

[Rwang8721]

Second thoughts - the white residue could be mineral salts leeching from the mortar. Definitely not concrete cancer though.

Hi VBPlease,

Thanks for your information. That plumber said the white residue are salts coming out of the concrete. Anyway the way it went was that he didn't say specifically to me what the issue is, but rather made a phone call in front of me to the strata manager and reported to him that there is a lot of "concrete cancer" on the rooftop. When I asked him what he meant by that, he pointed these white residue stuff to me and said they are "salts coming out of concrete".

He didn't explain much to me afterward and was in a hurry to go, so just merely said this isn't his job and that we should get a waterproofer looking at it.

 

[abra]

It's not a plumber’s job or a roofer’s job, you need someone in waterproofing Call a few that offer free quotes and get some opinions. Make sure they are informed over the phone of the problem and they are sure they can handle it, or maybe point you in the right direction. There are guys that deal exclusively in this area. Strata has a habit of sending every wrong trade to a job before they get to the right one

 

[Rwang8721]

It's not a plumber’s job or a roofer’s job, you need someone in waterproofing Call a few that offer free quotes and get some opinions. Make sure they are informed over the phone of the problem and they are sure they can handle it, or maybe point you in the right direction. There are guys that deal exclusively in this area. Strata has a habit of sending every wrong trade to a job before they get to the right one

Hi Abra,

Thanks for your opinion. Just wondering if you know any reliable waterproofing specialist who can help me out with this leaking problem.

I am not sure now if I can trust the strata manager and the plumber he sent, as the plumber, unlike some of those I called today, as soon as I told about the problem, they said it's not in their area to judge, and recommend that I would need a roofer or sb else to look into the problem. Where as this weird plumber sent by the strata just merely looked at the white flaky stuff and said straight away they are "concrete cancers". The next minute, the strata manager was talking to me how this is going to be a even bigger issue than the water leaking itself, and that I should allow him at least 3 or 4 months to get the paperwork wise sorted before any repair can be done. He even said he was going to commission an engineering report to look at the problem and have it tabled within 2weeks. However, from my earlier conversation with him, as stated in my earlier posts, he said usually an engineering report would cost 7k and that with the available funds at the moment, there is less than 2-3k in the balance.

I think overall this strata manager is contradicting himself and seems to wish to delay the repair work for some reason.......

 

[abra]

Off your other post when you mentioned concrete roof tiles I thought you meant pitched roof with actual roof tiles (monier). Make sure you mention it’s a concrete roof with floor tiles. Just remember Tiler/waterproofer not roof tiler as the two are very different and tradies will point you in the wrong direction. Call a few make sure they offer some kind of guarantee that they will fix the problem and what happens if they don't fix it. Also make sure they are licensed to do the work. Sometimes trades won't turn up for various reasons so make a list of at least 10. Sorry can't recommend anyone in that area atm.

 

[Ocean Architect]

Second thoughts - the white residue could be mineral salts leeching from the mortar. Definitely not concrete cancer though.

It's lime (calicium carbonate mostly) leeching out from the concrete based tile glue/grout. It comes off with a scrape and acid wash.

However, from my earlier conversation with him, as stated in my earlier posts, he said usually an engineering report would cost 7k and that with the available funds at the moment, there is less than 2-3k in the balance.

I think overall this strata manager is contradicting himself and seems to wish to delay the repair work for some reason.......

For a start, an engineers report does not cost $7 000. It costs far less than that.

Second, he wants to delay the work because he doesn't have the money. Put yourself in his position - he has inherited a huge block of units with a lot of problems, and no slush fund of cash to draw from, and so he has to wait until there is enough money in the strata account before doing anything. If, on the other hand, he got a loan in order to do the work, there is no guarantee that you guys can't kick him out as strata manager and leave him with the loan - so until either money builds up over time or all owners agree with pitch in a certain amount of money, in all likelihood, nothing is going to happen

 

[Rwang8721]

It's lime (calicium carbonate mostly) leeching out from the concrete based tile glue/grout. It comes off with a scrape and acid wash.

Hi Ocean Architect, sorry to trouble you again, but may I ask you if this means that this white stuff is certainly not "concrete cancer" as the plumber sent by the strata manager reported as??? and is this indicative of worn waterproofing membrane though? This is absolutely appalling and shocking with the way things are going at the moment.............

May I also ask you if this issue is indeed just worn waterproofing membrane, and if so, is the manager correct in saying that "just repairing the area where membrane failed is not going to fix the leaking (as they will fail for sure within the next 12 months), and the best way to attack it is to replace the entire roof waterproofing membrane, which in his words will take a long time planning again?"

 

[abra]

Get some opinions off people in the business if need be. Don't jump to the most expensive solution first. I once fixed a leak in a roof slab with literally one brush of membrane coating on a crack and it never leaked again (8 years so far).
It is too hard to tell off photos but it maybe a crack in the slab and the absence of grout in the tiles letting the water down- also is the drain pipe clear? Is the white stuff where the water is sitting and not draining away?

 

[Rwang8721]

Get some opinions off people in the business if need be. Don't jump to the most expensive solution first. I once fixed a leak in a roof slab with literally one brush of membrane coating on a crack and it never leaked again (8 years so far).
It is too hard to tell off photos but it maybe a crack in the slab and the absence of grout in the tiles letting the water down- also is the drain pipe clear? Is the white stuff where the water is sitting and not draining away?

Hi Abra,

The issue is that the strata manager is not keen at all to get into any sort of professionals to come in and examining the problem. All he would say is that, it is BIG EXPENSIVE PROBLEM which would require prolonged planning. He was the one that straight jumped into saying, in fixing a failed waterproofing membrane is not a simple issue and that the replacement of the membrane coating is required for the entire rooftop

As for your other question:
(1) Yes, there are cracks in the tiles where we would see water underneath the tiles
(2) The drain pipes are half blocked by the white stuff that were piling over it, most significantly in the corners of the roof.
(3) Yes, you are absolutely right that the white stuff are where water has been pooling and not draining away properly. -- Any implication on this?

 

[Ocean Architect]

Hi Ocean Architect, sorry to trouble you again, but may I ask you if this means that this white stuff is certainly not "concrete cancer" as the plumber sent by the strata manager reported as??? and is this indicative of worn waterproofing membrane though? This is absolutely appalling and shocking with the way things are going at the moment.............

May I also ask you if this issue is indeed just worn waterproofing membrane, and if so, is the manager correct in saying that "just repairing the area where membrane failed is not going to fix the leaking (as they will fail for sure within the next 12 months), and the best way to attack it is to replace the entire roof waterproofing membrane, which in his words will take a long time planning again?"

Rwang calm down for a second, it isn't concrete cancer. Here is the definition of concrete cancer from wikipedia to ease your mind:

http://en.wikipedia.org/wiki/Concrete_cancer

use some common sense also - people make driveways out of concrete that they leave exposed to rain/sun/water all day everyday for years and years, with nothing happening to it. What makes you think that the little bit of water on your concrete which is already covered with tiles anyway (tiles are waterproof, it's just grout that lets a bit of water through) is going to give you concrete cancer? C'mon, it isn't going to do that. Worst case scenario it'll weaken your tile glue and you'll retile sooner than you normally would by a few years. Big deal.

I've tiled for more than a few years and seen this over and over - it's lime leaching out of the concrete based grout. You see the same thing on brickwork that hasn't been painted/sealed, as per this picture:

So yes, drink yourself a big cup of "calm down" and relax, everything will come good in the end

In regards to your last question as per waterproofing membrane, as I said earlier, the only way to tell is to take a look. There may be a tear in the membrane causing the problem that you fix with aluminium foil sticky tape in 5 minutes. Or there may be lots of broken tiles on the roof that is swamping the membrane, with water sloshing over the edge of the membrane/between a join into your cavity. It might be a big job, or a small job, you just don't know yet, so stop stressing out about every possibility needlessly until someone gets up there and gives you a 100% answer.

I love non builders, they freak out wonderfully

 

[Ocean Architect]

Oh and on a topic unrelated to waterproofing membranes/concrete dying a slow painful death of cancer D) I still think that your strata guy is incompetent/ineffective. Get the owners together, kick him out, take control of the slush fund, fix it yourself, and contract a competent company to take control. The longer you wait, the greater the damage will be internally and externally with cupboards/ceiling plaster etc rotting out

 

[Rwang8721]

I love non builders, they freak out wonderfully

May I say I LOVE YOU wonderfully too Ocean Architect... Certainly felt so much better & reassured....

That plumber seriously freaked me out, as the moment he got on the concrete roof and looked at the cracked floor tiles & white stuff, he just said "concrete cancer, I see lots of concrete cancer". When I asked him what was the "concrete cancer" he meant, he just pointed all the white stuff as indicated in the photos uploaded.

When I tried to speak to the strata manager on the details of the plumbers finding not long after, (as said earlier the plumber was reluctant in explaining things to me at the time) the manager just replied, if concrete cancer is the cause of the water leaking then, he would need to get an engineering report to assess the overall damage, instead of just getting a plumbing report that he initially planned (in his words he was trying to save some $$$ for the OC) and it would be a long term approach going forward base on the findings of the engineering report, as the 'concrete cancer' problem as reported is much more significant than he initially thought....

I am right now so gobsmacked and speechless with this manager ...>.<...can't believe this is the extent of measure he took in attempting to delay the necessary repair work on common property ........I mean after all, if there is not enough funds to cover the work, he could have raised it through special levy and do the business as usual from there....why make a big drama out with all these lies? ..........................................

 

[Ocean Architect]

The plumber was talking about the lead up to concrete cancer. (I really don't like that term btw, it freaks people out needlessly). In short, in the beginning, water gets into the concrete and you get lime leaching out. If the water stays there for a long time, the steel reo bars in the concrete start to degrade/rust and the slab starts to lose strength. However, in my experience it takes way way way waaayyyyy longer than 7 years of wet tiled floor to produce that much damage. I have relatives who own 30 year old properties with uncovered, unsealed balconies that even pool water for half of the year (dodgy building in the 70s) with zero problems also.

The cracked tiles may be cracked because of failing concrete (highly, ridiculously unlikely in a 7 year old building) but are more likely to be caused by failing tile glue and people stepping on them or natural expansion/contraction of the concrete because of hot and cold weather.

If anything next time I get in touch with my engineer (he's in NSW and has been developing/building/engineering for 40 years) I'll ask him about this problem specifically in a NSW based context and put it to rest absolutely.

Can't believe we're talking about getting engineers to look at 7 year old suspended slabs. He's going to laugh at me I know it.

 

[Belbo]

There's another thing that could be involved, and that's a combination of 'concrete shrinkage' and 'brick growth'. Both are natural and can lead to loose tiles. (Our company just installed stainless steel retaining pins across an entire granite-clad facade because the panels were cracking from differential movement between floor slabs and brick walls of around 60mm!) It's not uncommon, but rarely causes more than a few superficial cracks in brickwork that can be patched with sikaflex.

The white stuff is calcium carbonate plus often ash and salts from the cement render behind the tiles / over the bricks. It is, as OA points out, entirely superficial.

Rip off the tiles, rip of the render, if necessary sandblast the walls, re-waterproof, re-render and re-tile. No biggy.

Concrete cancer presents as falling chunks of concrete. Your tiler is having a lend of you. I bet his quote is outrageously high! Mine would be too.

 

[Rwang8721]

The plumber was talking about the lead up to concrete cancer. (I really don't like that term btw, it freaks people out needlessly). In short, in the beginning, water gets into the concrete and you get lime leaching out. If the water stays there for a long time, the steel reo bars in the concrete start to degrade/rust and the slab starts to lose strength.

LOL, OA, you probably won't believe it, but you know what my strata manager is telling me instead? He was saying, as plumber reported seeing a lot of "concrete cancer" on the roof, it is thereby more importantly to commission an engineering report that looks at the overall extent of the 'cancer' throughout the building complex and address the 'cancer' issue first, because if the problem is left undressed, any further contraction/expansion of the steel reinforcement over time would result in continued failure of the waterproofing membrane, as it will always get torn apart by the steel movement overtime.

This is complete opposite to what you and Belbo are telling me here lol...right now, I will chase him again to get a waterproofing specialist to come in and address the problem.....

Lucky that I really asked for your opinion here, otherwise I would be waiting for a-forever-engineering report to arrive hehe.....

 

[Ocean Architect]

There's another thing that could be involved, and that's a combination of 'concrete shrinkage' and 'brick growth'. Both are natural and can lead to loose tiles. (Our company just installed stainless steel retaining pins across an entire granite-clad facade because the panels were cracking from differential movement between floor slabs and brick walls of around 60mm!) It's not uncommon, but rarely causes more than a few superficial cracks in brickwork that can be patched with sikaflex.

The white stuff is calcium carbonate plus often ash and salts from the cement render behind the tiles / over the bricks. It is, as OA points out, entirely superficial.

Rip off the tiles, rip of the render, if necessary sandblast the walls, re-waterproof, re-render and re-tile. No biggy.

Concrete cancer presents as falling chunks of concrete. Your tiler is having a lend of you. I bet his quote is outrageously high! Mine would be too.

This sounds like Greek Style Quoting. $7000 total. $3500 for the tiler, and $3500 for me - want the job?

 

[Belbo]

How did you guess? I work for a couple of Greeks!

 

[Ocean Architect]

How did you guess? I work for a couple of Greeks!

Me too!

...My mother.

Every time I call her, I get loaded up with work. Last week was concrete and roller gates. Tomorrow is yardwork followed by painting. At least your bosses pay you with money. I get paid in earbashings and whingeing.

Now if you'll excuse me, I'm going to go and feel sorry for myself

 

[ashalim]

I love non builders, they freak out wonderfully

Guilty as charged