Cracks in concrete water tanks

In the Karoo (very similar to western Australia we had similar problems in the western side. Painting in a dark paint will exaggerate the uneven accumulation of heat and resulting expansion contraction and cracks.

If you don't have dolomitic water the chalky stuff may be calcium from the cement leaching out.

I would complain in writing to the manufacturers especially if they did not specify the no paint exclusion in writing.

To solve the leak we painted the inside of a leaking concrete or masonry container with a mixture containing cement and milk. Maybe we used milk because it was available.

An epoxy paint will also work.

looks like it might eventually collapse.

Best call the makers and follow their suggestions, which might be to sand blast it. OR??

what happened to the tank?i cant see paitining it would cause any harm,but mind you the cement silos around here arent painted or have i seen a painted one just a cement tank,theres a cement called speedcrete,it goes int the capaitutoris ,minutre cracks and seals it,sorry bout the spelling

I shall take it up with the manufacturer ASAP.

I do not understand how paint and partial sun exposure (say 2-3hrs in arvo) can cause essentially a new tank to crack and leak? The issue for me now is that as soon as they see the tank has been painted they will most likely try adn get out of rectifying the problem. Just want to be comfortable that dark coloured acrylic paint and partial sun exposure is not entirely to blame with cracking a reienforced concrete tank. It just didnt make sence in my non engineerign mind? I woudl assume its more to do with thickness of the wall and coverage of the reienforcin steel??

Absolutely a dark paint can cause a tank to crack. The tank will be more resistant with proper reinforcement, however a dark tank, in direct sunlight, will expand and contract differentially and tear itself apart over time, beginning at the weakest strength of mass areas. Stabilizing the wall temperature with water will help.

As a U.S. contractor I was actually directed by an engineer to paint the outside of an inadequately reinforced concrete tank with a black impervious tank liner material. (Their idea was to keep ground water from leaking in). The sun on the black material caused tremendous expansion resulting in cracks approximately every 13 feet around the (rectangular) tank. They recommended that the owner not pay for the project and put my compay out of business. Lawyer said I had a winning case, but couldn't afford to pay for his time after the design engineer dragged the case out over 7 years with legal appeals.

Paint over the offending paint with a proper paint as soon as you can!!!

The sun exposure in some places in Australia is highly destructive.

Mum and Dad had a garage built on the western side of the house. The fibrous cement sheeting (hardiplank) cracked due to thermal expansion. On a hot day those cracks opened to more than 30mm.

Imagine inside your "hot" concrete, the re-inforcement steel is expanding due to the increased heat absorbed by the painted surface in the sunlight AND then at night is contracting due to the increased heat loss through the dark surface. The stresses that this would create will not necessarily be isolated to the painted area.

Re-painting the tank may halt the deterioration and then there are remedies for the microfissures that are already in the tank.

If the tank is larger than 25,000l, have it demolished!!!! Again on mum and dad's farm, I saw the remnants of a 25000l tank that failed. There were pieces of concrete 1m square more than 4m from where they started, and we know the tank was not full.

Hi

You need to try "Corium99" from "Magna" alloys only two colours Red Green manufactured in Australia. I used this to actually SEAL cement water tanks in the late 70's here in South Africa. Unique Paint, 3 x weight of normal paint. uses a pigment derived from a plant that lives submerged "Lignum vitae" expensive, approx USD$1/L in the 70's. Amazing stuff. Demo like:Take empty tin can knock many holes in its bottom with six inch nail paint allow to dry, fill can with water, boil with open flame, throw water out, note no leaks, sudden quench in cold water, batter with hammer, note no paint cracking. Buy it if you can find it, paint your dam and introduce yourself to a host of other amazing products by this company. Regards2U

Hello Metman,

this paint with Lignum Vitae is the heaviest wood and actually sinks in water.

It sounds just the stuff for the cracking tank.

I once visited a fish selling place(goldfish etc) and the tanks were paints a sandy colour.

babybear

Welcome aboard! As you've already seen, the answer is yes to your original question about painting the tank. But I have seen large concrete tanks underground that have developed cracks over time. It's just a property of concrete, and without special blends or treatment, will happen anyway. Concrete has microscopic pores that will fill with water, and due to differential heating and/or ice expansion (where freezing temperatures are encountered) will also contribute to this. If it's potable water, there are rubberized coatings for the inside (like what's used in swimming pools) that will seal the walls and keep the water drinkable. If only for irrigation, etc., this may not be necessary.

Dear ANDESPANDES!

You have a few problem on hands. First, the manufacturer is not knowing what it is doing, and you in the other side you painted dry concrete with dark colour which absorbing heat.

My suggestion is to empty the tank, let dry one or two days the surface only, and widen cracks with a chisle. Wire-brush all powdery materials. Mix 2-pack epoxy coating (Parts A+B in volume at recommanded ratio) with dry silica flour to create a heavy malleable paste as patching compound and fill with a spatula, knive or similar tool all cracks. Let cure the repair for overnight. Apply the same 2-pack epoxy coating (again mix A and B in the correct ratio and follow the instructions on the label). The coating could be clear or white. For outside of the tank I suggest to use the same 2-pack white epoxy coating or Infra-Red reflective epoxy coating.

Buy your 2-pack epoxy coating from a manufacturer specialized in these types of coatings. I am Canadian but you have on your continent the same we have here.

If you need more information, ask, Gil.

Good fix.

Also he should paint the outside white or shade from sun to reduce the expansion/contraction.....

For the future for everyone:-

Never paint anything while under guarantee.

Read the fine print fully through BEFORE purchase....

Remember, now the manufacturer can now wash his hands of the whole problem and it might still have happened UNPAINTED!!!

Hello ANDY!

I want to make a correction: I talk about solventless or 100% solids 2-pack epoxy coatings. I hope the Aussie will catch it and don't use any solvent-based product.

However, the tank manufacturer like many all around the world, they make things without have any thaught about the customer who pay and use without knowing what to do. The user is the innocent loser in many cases.

Andy, your recommandations are correct because you know what you are saying. The Aussie, she/he just pay for it and use it as many other things.

I wish her/him to succeed with the dammaged tank. I hope no one come between and tell him to do something else for another disaster!? Von Clausowitz said the same as Churchill did.

What will be the medal position of China, USA, Aussies, and Germany after the Olympics? Your answer will be appreciated, Gil.

I agree with your comments.

With regard to medals I haven't a clue......hopefully we get a few!!

Hello ANDY!

I want to correct my first note: 2-pack epoxy coating must be solventless or 100% solids without any solvent. During the last 25 years I don't make or I don't buy any solvent containing products (except water as solvent). I hope the Aussie will catch it in time and don't use some solvent-based epoxy coating.

Addition: How can in the new century, one manufacturer make important and expensive objects and does not inform its customers what kinds of difficulties could happen. It's like one of the most respected paint manufacturer in North-America send every month a page long of deffective paint list. For example, the ceiling flat is seedy or the hiding is less than usually. Return all acrylic semi-gloss latex with excessive foam during application. They forget to add defoamer at the let-down? It's real in 2008? Yes, because many companies don't have any really qualified people to run the manufacture with people, machines, and without standard operating procedures made and approved by competent technicians. I cannot hire someone to replace me during my vacations because lack of general knowledge how to run people and manufacture simple things like sealers, stains, and paints. They have ability to work in the lab but nothing in the plant. Some of them can handle people but they have no technical know-how. So, I don't have vacations but the business makes good products.

All these different lack of knowledge in an organization create problems to customers who already paid for the product(s) and need to pay for the troubles to.

Do less and do it better, Gil.

Hello andespandes:

how about either a Butyl plastic/rubber liner as in fish ponds. Or a fibreglass liner with the fibreglass continued over the top and down the sides of the tank?

As has already been said dark paint is anathema to concrete in the sun.

My suggestion will stop the leaking at least.

babybear

Hi BABYBEAR!

ANDESPANDES' concrete tank has structural problems, which cannot be solved by a simple coating inside or outside. Elastomeric coatings crack after a certain time, so we have to take care about the existing cracks. The steel bars are probably already rusted, and it's very hard to stop. Need injection of epoxy compound? I don't know but possible. The elastomeric coating will peel off rapidly because the lack of adhesion. When adhesion is questionnable, after my opinion, we don't solve any problem. The dammaged concrete must be adequatly repaired as mentioned in my previous notes, and the concrete must be protected with a water un-sensitive, water resistant, Infra-Red reflective, high-built, solventless 2-pack epoxy coating.

If you have a better solution, please let us know. We want to learn better than we already know. However, my suggestion is one of many, so I wait like many other with or without opinion. All the best to the concrete and the top solution for the tank, Gil.

Thanks everyone for your feedback to date.

As mentioned within the thread the whole problem here relates to inadequate communication between the manufacturer and purchaser. Coming from a non-engineering background I can understand that you would not be able to construct anything on the tanks etc but a simple paint job would seem acceptable. The tanks are located on about 20% slope and are highly visible, so a paint job to make less conspicuous seemed innocent enough. Who would have thought it would have such significant potential for damage, certainly not me. Anyway I have called the manufacturer to come and inspect the tanks and advise on rectification ASAP. I shall keep you posted as to the response. Cheers, Andespandes.