waterproofing cement tank

EPDM liner would have longest life.

Have not used this personally, but it is what comes to mind, if inside a tank personal safety I think would be very important.

Regards JD.

Please note "not for potable water".

Sorry you cant use epoxy for potable water. Best way will to give linning of water proof cement.

USING NON-TOXIC EPOXY RESIN NO PROPLEM WITH THAT BUT ON THE LONG RUN HE WILL SUFFER AGAIN FROM LEAKAGE,FIBER LINING IS MUCH BETTER BUT MORE EXPENSIVE

Hi, With my father we rendered around 50 tanks in the last 30 years. The only ones that leaked were insufficient cement in the mix. (Local sand was too coarse.) The fix for those was to make a cement "slurry" and mop it onto the concrete surface. Sometimes, they just "seal up" by themselves depending how bad the leak is.

From your description though, I suspect your problem is due to movement at the joints. You will NOT overcome this with render as the differential strain at the bottom and top of the tank continue to change as the tank fills and empties.

You will most probably need a flexible liner of some sort. The cheapest would be "brushable" sealant like that used to create waterproof membranes in housing construction. It's like a thick PVA with fiber that will bind across the movement and is still able to stretch with the tank movement. Suggest to put a 50mm joint tape where your seams are to help build a thicker (more durable) seam at those locations.

Second option is to use "betanite" clay. It floats in suspension and when it gets into a leak, is sucked in and then somehow expands to fill it and eventually seal it. This means you cannot use the tank water for some time and have to keep it full. (If you know where the leak is, you can smear some clay mix on th einside there and the results will be faster and more obvious.)

Third option is to get a liner for the tank, but there you will need a specialist to make it to size (unless you're really luck and have a standard size.) and then fit it in such a way to ensure it doesn't collapse while the tank is empty.

www.xypex.com

www.kryton.com

My fellow Australian "Just an Engineer from down under " has obviously a lot of experience and good sense. Australia with its constant and regular droughts needs all of that and then some !

I would add a few thoughts and suggestions:

1.If the leaks can be spotted or assumed to be on the shell plates then I suggest that you look into tightening of the steel bands . These may have stretched and they often require regular tightening as with heat they do expand . This could be the direct cause of the leak(s)

2.If the position of the leaks can be spotted then using the old tools of the marine carpenters and caulking with a mixture of hemp and tar will in many cases stem the leaks. If the joints or leaks are very small it is best to use threads of cotton with the caulking tools.

3.Finally you have not indicated how the bottom plates are assembled or if it is a slab. If that is leaking then you need to pour a further 2 " to 4 " concrete of strong mix, above it , in order to be sure that this source is stemmed. Generally an asphalt paper liner on which asphalt is spread hot is carefully fitted on the bottom of the tank before pouring the 2" to 4" concrete mix

All of these simple corrections should be considered and tried. If they are done properly and work ,as they generally do , then you will find they are infinitely cheaper than a new tank or even a liner

Labor Omnia Vincit

I sugest you to coat the interior of the tank with spray applied polyurethan membrane from Rhino Linings. They can make the coat from 1 /16 to 1/4 in 1 coat (seamless) and it will be ready to use in the next hour. There is many applicators in the states and over the world. It is a bit costly but it will never leak again.

Good luck in your project.

CG

Google "Roman Cement" the original waterproof cement. Or use alytex as for a swimming pool liner.

Yes, there are all of the above, PLUS, simply applying brush applicated moisture curing URETHANE. There is a commercial brand which we use. It cures to an inert membrane, and has proved to be food grade. It does take some days to achieve total cure in low moisture (humidity) atmospheres, but with the fact that it penetrates deep into the concrete and the application of three coats, you'll have a tank which will take acids if you want to, and will cope with the expansion cycles of the substrate for many years.

Be happy advise further if you'd like.

Cheers

S.

Hello Stueywright ...would you have any brand to re-command ????? I am in Northern NSW ...Murwillumbah ....well west of it 30 kms ...Thks Rgds Yves

Yves,

Yes. The brand is P.O.R.15. Go to ppc.au.com and quote my name as the informant to get the best service.

Rob or Jan will be very helpful and can arrange delivery to you of the neccessary quantity of Tank Sealer, although I've used just the clear rust paint, 4coats, to excellent effect. Don't put it on too thickly. It'll effervesc CO2 and ruin the job. Really stretch out multiple thin coats to get the best job.

I'll be always available to answer any query on my email stueywright@msn.com

Cheers,

Stu.

I suppose the most difficult problem is locating exactly where the leak(s) is/are.

It is possible to have the inside of the tank sprayed with a sealant or you could put a plastic liner in the tank. There are many options open to you...........if you are going to use the water for domestic purposes, ensure that you select an appropriate material.

Where you live of course is also going to affect the options available to you.

Size is not a problem most companies can line anything from a small fish pond to a reservoir.

Just look on the net under tank linings.

I grew up on an island in Puget Sound and our water supply was from a spring in the hillside about 60 feet elevation higher than our home. My dad constructed a tank that had a concrete pad about 6 foot square 20 feet lower and 150 east of the spring. The sides were cement blocks about 4 foot high. The spring trickled into the tank 24 hours a day and supplied our water supply. I remember helping build the whole system when I was about 14 years old. My dad bought a potable water black emulsion that we liberally coated the inside of the concrete floor and concrete blocks with several times. That was in about 1960. My parents both died and when I sold the house in 1996 the coating inside still worked and didn't leak. The brand? I don't know.

Hi,

I was in the fish pond industry. And we used to sell fibreglass ready moulded ponds. Or if a hole was dug we could line it with Butyl plastic liner. It lasts only 20 years though.

In your case your could use the tank you have as a mold and, lay large sheets of fibreglass in and around the tank. The easier way to do it would be to use flat ready-made sheets, and assuming the top of the tank is open, you can also buy ready made angle to fit round the bottom. Make saw cuts in the fibreglass angle to allow it to bend. Then as you put the sheet on the sides you can layer fibreglass sheets to cover the joints as well as covering the whole surface of the Angle where it is cut to fit to allow bending and fitting. Make the top edge of the tank sound before you lay and 'paint' the epoxy onto the fibreglass. I would make this top cover over the edge at least a foot and make the glass fibre as thick as possible for strength.

If you could do the fiberglassing yourself using woven mat and plain sheet that consists of woven glass fibre only, it will best fit all the different contours of the tank. And so be a very good fit with no spaces between the tank and the fibreglass.

jfmfit

We repaired our in-ground fishpond with the brush applied urethane. Didn't know exactly where it was leaking, but as it was constructed of Besser blocks ( Breeze blocks to some) and then rendered and veneered with Slate, 50 years ago, and was deformed by the roots of Chinese Elm tree nearby, I decided that to trace the leak through the many cracks was too hard.

I cleaned the entire emptied pool with Marine Clean, twice. Let the pool dry completely, and then brushed on three coats of POR15 clear ( so as to let us still enjoy, as much as possible, the slate) The coating process took just one day, as this stuff cures fast in humidity. Let it breathe for a couple of days, filled with water, and added fish. Presto.

That was a couple of years ago. No leaks as yet and don't expect any. I've used this stuff for many years to 100% success each time. Oh! almost forgot, this pool is 20 feet in diameter and three feet deep.

When I was a kid I helped a mate of my Dad's build tanks around the country. These were concrete slab base with corrugated gal. iron set in. open topped. The panels of iron were bolted together and the gasketing was a bitumastic called Hydroseal. Still available at good hardware stores.

Cheers,

S.

Finding the leak is really quite easy, fill with water, do not use any or take any water out, the tank will go fairly quickly to the level of the leak and stay there.

Mark carefully and then empty the tank.

Carefully seal with your chosen sealant that area that you marked and an inch above and below.....

I did this recently (2 years ago) for a friend's rainwater tank here in Germany, works fine still!! I used a cheap brush on sealant that is available all over Germany, its like a liquid Duck tape......

Hi Andy,

How big is the leak?

How big is the tank?

He may not have 6 months to wait..............or have I missed something...........I don't know..............but a good idea if applicable.

Sorry............just nit picking.

Pick on anything that should be noted, its always good to have someone checking up as nobody is perfect.

The last perfect man was hung on a cross!!!

I call it "Team Work" as you do too I expect.....have a great day and stay cool!!

I used to be conceited once................now I'm perfect!!!!!!!!

Is that looking cool

OR

Getting cool

This is a Nordic holiday................nice to see............not nice to be there ...........too cold for me Chief.

ALTHOUGH, I must admit it would be a wonderful experience to see the "Northern Lights"........maybe in Alaska.......maybe one day...........I have looked at driving from Vancouver to various points in Alaska..........looks beautiful but cold.

June in Scotland, there you will see northern lights!!!

Is that after dark, Andy?????

No, its in the "Gloaming" and later......

Please use any Scottish to English dictionary for a definition!!

Or ask me as I am off "Roaming in the gloaming, on the Bonny Banks of Clyde"!!!

Ryno liner!

Don't laugh, tanks and containment is where this stuff first got its start.

Sprayable tank linings.

Hello leaking tank owner!

Any concrete and/or masonry work must be repaired with solventless/100% solids 2-pack epoxy compositions. Crack must be filled with injection compound, all surfaces must be painted with same type of coating. Epoxy is the best to hold water or resist to water, depending what users need. Religiously follow all surface preparation recommendations. Through Internet you can find responsible manufacturers for epoxy adhesives, coatings, and other products. Good repair from Gil.

Gil,

Rubbish!

Have used non-epoxies for 20 years, namely urethanes. Urethanes cure to more flexible membrane than epoxies, of which most cure HARD. Most people have this notion that epoxies are the cure-all for everything. They are not. We DO use epoxies where they are indicated though. You could use it in this case, but if you want a low labour, cost effective repair you can also look at the urethanes I've mentioned in prev. blog. There are some things you simply don't have to do. If the tank is not structurally sound then rebuild it, properly. Always cheaper in the long run. "poor man always pays twice" - prov.

There are more ways of killing a cat, than chokin' him with butter.

No offense meant.

Cheers

S.

Hello S.!

No argument with you but, only after my experience, urethanes cost much higher than epoxies. Also, it's harder to make a customized hardener, isocyanate, then make an amine adduct, which costs much less than buying a pre-reacted hardener. Epoxies could be made solventless and low viscosity. However, 100% solid urethanes are higher in viscosity and cannot spread as far as epoxies can go. Adhesion of epoxies are much better on concrete or similar materials than urethanes but both could be done, let say, it's a matter of choice and performance requirement. Let the user make the best choice with different suggestions he got. Sincerely yours, Gil.

Inexpensive coatings for concrete exist. Spraying Polyurea is not adequate for extended life. Their adhesion is compromised. They are quickly returned to service, but are inferior to epoxy systems.

I have removed all sorts of failed sprayable liners (included the one referred to earlier in this post), only to apply epoxy coatings (adhesion values and flexural strength get close to the compressive strength of concrete and leave the cohesive strength of concrete far behind).

With a worldwide network of Distributors and 55 years in the business, I trust Belzona with their Belzona 5811 (Immersion Grade).

www.belzona.com

Good luck.

Hello again!

Belzona 5811 (2-component coating) is fitting to the purpose, however, you have old lining which must completely be removed or sanded before any coating application because adhesion could be a problem on hard and glossy surface. All the best, Gil.

Inexpensive coatings for concrete exist.

Wax would do

This is an excellent and simple solution! However, there are many waxes available on the market and for the user's benefit, it's important to specify what wax will perform. Again, excellent suggestion but need precision. Please, tell us what's your exact recommendation. We all will be grateful! Thanks again, I learned something valuable, Gil.

I realize this is an old thread but I think this may be useful to anyone searching for an answer.

Thoroseal is Recommended for aqua-culture & potable water.

http://www.chargar.com/DATA_SHEETS/Thoroseal_DATA_SHEET.pdf