What to mix with cement to make waterproof concrete?

[Sheryl]

Can someone suggest a product (by local brand name, picture if possible) to mix with cement to produce a waterproof concrete?

Needed for a small "moat" around the house to keep insects at bay

Thanks!

[eyecatcher]

This is what i add to mortar or concrete for a bathroom floor.

Also good to add it into a weber floor tile adhesive also....even emulsion paint.

Makes the mortar or cocrete quite sticky.

This is a common brand available at many diy stores.

[lovelomsak]

I donot know how to water proof the cement by mixing in the cement. But I know a great product for sealing it after it is made. Crocodile Flex Shield. This stuff works great sealing concrete. Just mix and paint it on.It goes on easy and dries hard and strong.

[cooked]

Naam jah is available most places

[NeverSure]

Concrete is never waterproof. You have to seal it. It's really important to work the concrete to compact it and force out tiny air bubbles. This can be done with trowels.

In the West when making swimming pools the concrete is applied by spraying under fairly high pressure, and then worked soundly with trowels. It is either sprayed as a dry mix with water being added at the nozzle ("gunite") or as a wet mix simply blasted under pressure ("shotcrete"). It can be applied by hand with trowels but they have a bunch of guys really working it hard with trowels to compact it. I have never seen a swimming pool being "poured" in the USA.

The more the concrete is worked and compacted and air driven out, the stronger and more water resistant it will be. Then when it cures you can apply a sealer.

Cheers.

[Jing Joe]

I've used waterproofing additives that mainly have PVA in them.

You can use much less water and doesn't need water to cure.

That white waterproof woodworking glue is probably the same but dearer than the industrial quantity of concrete additive.

If you have some glue try a sample. Try using much less water.

Good luck.

P.S. Helps make small patching up jobs stronger with plain cement with small qty PVA and water.

Edited January 30, 2016 by Jing Joe

[worgeordie]

For a small moat around the house !,to keep insects at bay,!

I am sure you know most insects can fly,and the moat will

turn into a breeding ground for Mosquitoes,the insects that

you really want to keep at bay, unless you were only joking?

regards Wogeordie

[DMC1]

Sika-101a from Homepro. Yellow tub with red triangle logo. I use this to coat the concrete on my fish pond.

You do not mix this with the cement but mix and paint on afterwards. This product is - waterproofing slurry & moisture seal. Clear instructions on the tub.

Edited January 30, 2016 by DMC1

[tomyumchai]

i was browsing in hardware house yesterday, there must have been 15 different waterproofers and additives on the shelves. sika and many other imported quality brands too.

[Shawn0001]

You cannot make concrete which is completely waterproof but you can reduce it's permeability by about 70%.

There are two options, a concrete admixture or a paint on sealer. Admixes are the only long lasting solution.

There are four types of admixture, latex is the worst as it does not fill cracks that appear after pouring. The third from best is adding silicates to the mix to increase density, this helps but not that much. The second from best is a hydrophobic admix such as soap which can reduce water ingress by about 50%.

But the best by far is a hydrophilic crystalline admixture, such as this one from Xypex.

http://www.xypex.co.th/index.php?option=com_content&view=article&id=25&Itemid=137

That is the best, but that's what we use for tunnels and the like, for a shallow trough as I imagine you are making, just regular concrete will be fine as long as it is reinforced, I would suggest some fibers in the mix as well as steel reinforcing.

[Morakot]

You cannot make concrete which is completely waterproof but you can reduce it's permeability by about 70%.

Concrete is never waterproof. You have to seal it. It's really important to work the concrete to compact it and force out tiny air bubbles.

Absolutely correct the above two posts!

Also to reduce permeability, the water-agregate ratio should be altered carefully. Increase the grain size of the aggregate and reduce the amount of water.

Basically use less water and crushed rocks (mixture of varying sizes, between 1/4" - 2") instead of gravel.

Edited January 30, 2016 by Morakot

[BlindMagician]

For a small moat around the house !,to keep insects at bay,!

I am sure you know most insects can fly,and the moat will

turn into a breeding ground for Mosquitoes,the insects that

you really want to keep at bay, unless you were only joking?

regards Wogeordie

This was my first thought too. Rethink the moat idea...don't fixate on your home being your castle.

[maderaroja]

Thank you for the information.

[jacksam]

For a small moat around the house !,to keep insects at bay,!

I am sure you know most insects can fly,and the moat will

turn into a breeding ground for Mosquitoes,the insects that

you really want to keep at bay, unless you were only joking?

regards Wogeordie

Agree fully. What a crazy idea. Also how do you intend to enter your home. Jump? There exist much better methods. Also what your suggesting may in future become illegal with a dengue fever bill.

[steve73]

I had a small fishpond built next to my house using "traditional" methods... 70mm concrete bocks, with 10mm render (same as you'd put on any wall), and then a thin skim of pure cement slurry well worked onto the surface, and polished with a steel trowel.

No use of any admixes or PVA at all - despite my concerns and suggestions...

8 years later and it still holds totally leak free (except one area where a tree root cracked the wall - which I repaired using the same cement slurry method).

[steve73]

Re. the issues of "moats" being a breeding ground for mosquitos, etc, just make sure you keep a few fish in there... guppies (or fan-tails), or mollies are easiest to keep and will readily breed.

Thai houses traditionally have small ponds, or fountains with a few fish around them... the water attracts the mossies (rather than them going into the house), and then the fish eat both the insects and any larvae that emerge from any eggs that do get laid.. Natural insecticide..!!

[Lantern]

PVA glue or Bondcrete, both the same.

[ronaldo0]

You wont make it waterproof by making concrete.

In homepro there is the stuff you paint on called D150 I think it is. This makes it waterproof but makes a rubber film on what you brush it on, looks like silicone you would seal a sink with once dry.( effective but not pretty )

The other stuff I have just painted onto my patio area and soon around the pool is made by TOA . It is like a clear lacquer that comes in 5 litre cans and you brush it onto the concrete/stone whatever . It cost 5oo bht per tin and there are also several other brands upto 1700 bht per tin . I powerwashed the hell out of the stone and let it dry fully for 2 days before applying the lacquer . It now has a clear polished coating on it that reduces how quickly is will become dirty with rain and when I wash it again it will be a million times easier to clean ! ( but take note, the area it says it covers it nowhere near what you will get using it)

[Jing Joe]

PVA glue or Bondcrete, both the same.

Bondcrete, yes is great as glue too and that's the product I was thinking of too, BUT in a footnote on an old container of mine says;-

"Bondcrete is not suitable for wet areas and waterproofing applications."

Maybe their web site will have an improved version?

Funny how I've found it worked for me though.

P.S. As someone posted;- fish of course are a must to eat the insects.

But why a moat to control existing insects?

Maybe the moat will attract the existing insects ? so then;- up and at em them with the fish?

Edited January 30, 2016 by Jing Joe

[Eric Loh]

I suggest you use a silicone base product. In our tropical weather, silicone can withstand heat much better than any other water repellent products.

[Bruce404]

As indicated by some above, concrete when properly installed is fairly water-impermeable, if not "water-proof".

The problem is that it is often not properly mixed, with workers adding too much water to make it easier to mix, work, and flow. This actually weakens its eventual strength and lowers its impermeability.

The dryer the mix when poured (the less water), and assuming sufficient cement, the better, although this makes it harder to pour, to spread out, and to vibrate within the forms to get any air pockets to float up and out.

In addition, once it has hardened a few hours, it is important to keep its surfaces wet for a full month to continue the curing and strengthening process. This requires covering it with burlap and/or plastic and constantly wetting it down, and perhaps keeping the soil around it well-watered.

For obvious reasons of inconvenience and ignorance, this is often not done in Thailand and elsewhere. So some of the various coatings mentioned above would help. Concrete/gunite swimming-pool installers (and their websites) might have some useful advice and techniques on this. In fact, maybe you should hire one to install your "moat".

Edited January 30, 2016 by Bruce404

[Thorgal]

Water barrier won't work to keep the insects away. "Au contraire"... Higher degree of humidity (which you will create with your water volume+evaporation) will attract more/different insects and animals like snakes.

Variations of species of insects are "mainly" determinated by the elevation where you live. You won't stop that with a water barrier.

Even so, to design or determinate your concrete, a minimum of sizing is required with details of soil. With this feedback we will be able to consider soil improvement and/or specific reinforcements with of without chemical additives to keep concrete of the moat waterproof and dampproof.

Please consider also concrete strength in order to avoid future micro cracks...in function of the water volume/weight you plan to use...

Edited January 30, 2016 by Thorgal

[Kiwoz]

Of course concrete can be made 100% water proof without sealer. I have built many reservoirs and water tanks, never used sealer, they never leak.

Also I have built ...poured concrete, for Olympic size swimming pools....They don't leak. Maximum size 16mm aggregate. 40mpa.

[khunPer]

If you mix the cement yourself TOA 211 makes it "waterproof" - also great to add little of when lender/plaster, as it stops almost all cracks (I used it with great success, when workers plastered my house).

Another product is Sika 102, that is a ready mix, only water to be added. Cures/dries very fast and normally used to repair smaller holes.

Hope this will help you (and apologize for not cleaning my long time stored TOA 211 before snapping the photo, the Sika however is fairly fresh from HomePro).

Edited January 30, 2016 by khunPer

[DMC1]

Here's the Sika I used on my fish pond as posted earlier. ฿350.

Edited January 30, 2016 by DMC1

[Kiwoz]

If you mix the cement yourself TOA 211 makes it "waterproof" - also great to add little of when lender/plaster, as it stops almost all cracks (I used it with great success, when workers plastered my house).

wIMG_1711_toa211.jpg

Another product is Sika 102, that is a ready mix, only water to be added. Cures/dries very fast and normally used to repair smaller holes.

wIMG_1712_sika.jpg

Hope this will help you (and apologize for not cleaning my long time stored TOA 211 before snapping the photo, the Sika however is fairly fresh from HomePro).

These products are great for Render/Plaster... Not necessary for properly mixed and vibrated Concrete.

[sead]

I've used waterproofing additives that mainly have PVA in them.

You can use much less water and doesn't need water to cure.

That white waterproof woodworking glue is probably the same but dearer than the industrial quantity of concrete additive.

If you have some glue try a sample. Try using much less water.

Good luck.

P.S. Helps make small patching up jobs stronger with plain cement with small qty PVA and water.

[Sheryl]

For a small moat around the house !,to keep insects at bay,!

I am sure you know most insects can fly,and the moat will

turn into a breeding ground for Mosquitoes,the insects that

you really want to keep at bay, unless you were only joking?

regards Wogeordie

Agree fully. What a crazy idea. Also how do you intend to enter your home. Jump? There exist much better methods. Also what your suggesting may in future become illegal with a dengue fever bill.

It is a very small trough, easily stepped over.

No, I am not joking. I have one around my house, have had now for almost 20 years. It is an absolute necessity where I live in order to keep out scorpions, millipedes and centipedes, and slow down (though not 100% keep out) the ants.

It works quite well and I have absolutely no problems with mosquitoes, probably thanks to the fact that frogs use it for breeding so it's full of tadpoles.

I am now building a small house next to my property for caretaker/household help to live in, need to put it there as well.

Thanks to those with suggestions, especially those who included pix!

[Rimbuman]

You cannot make concrete which is completely waterproof but you can reduce it's permeability by about 70%.

There are two options, a concrete admixture or a paint on sealer. Admixes are the only long lasting solution.

There are four types of admixture, latex is the worst as it does not fill cracks that appear after pouring. The third from best is adding silicates to the mix to increase density, this helps but not that much. The second from best is a hydrophobic admix such as soap which can reduce water ingress by about 50%.

But the best by far is a hydrophilic crystalline admixture, such as this one from Xypex.

http://www.xypex.co.th/index.php?option=com_content&view=article&id=25&Itemid=137

That is the best, but that's what we use for tunnels and the like, for a shallow trough as I imagine you are making, just regular concrete will be fine as long as it is reinforced, I would suggest some fibers in the mix as well as steel reinforcing.

Excellent! This stuff is around for along time, in the past (like history past) this was added to cement for masonry in water walls and bridges and held up for many centuries.

[Sheryl]

If I can add another somewhat related question:

can anyone recommend a local brand of a sealant for bathroom tiles? (with pix if possible)

I find the recommendations of shop staff to be pretty unreliable....

Thanks!