eq1:
High water table wouldn't affect ICF any more than poured walls.
Legallett is great.

Kevin

If there is that much water against a concrete or ICF wall it is not going to matter much, with salt, the standard design is to use 4,000 PSI concrete OR 3" clear cover over steel, sometimes with blinding which is topped with damproofing, however, the effects of ground water on an ICF wall is very, very minimal, and not worth looking  at.  Kind of like thinking about the effects 500 years in the future, the concrete will already be loosing more strength from age and wear than from water degridation.  That and the damp wall is 2.5" away from anything due to the foam, even if it was a problem, as well as the fact that your floor slab is going to be the worst damp concrete issue you will have, over your walls.  Additionally, with ICF you could trap any excess moisture in the wall, by sealing the bottom, as the sides are already sealed, and evaporation or free runoff would be retarded, increasing the level of moisture.  Imagine also if you had any water entering the wall above grade, as many posts in this forum have stated.

 

Mark Ross

Mark,

You bring up a good point in that the concrete in an ICF is sealed by the foam and any retained moisture would have a hard time evaporating. So, how about stripping let's say a 12" band of foam from the concrete on the outer perimeter that is shielded by a waterproofing dimple membrane. This would allow at least some open area to be exposed to air and evaporation. Or is this simply talking about it too much? The ultimate question is how high water can rise along a concrete wall.

Thanks,

Leonard

Leonard:

My main point here is that it is so small, its really irrelavant, compared to concrete or block, ICF solves the problem by about 95%.  If we are happy with block and concrete performance, then ICF is just a better way.

Hence, wicking effect really plays little to no role in ICF's, comparitively.

Mark Ross

Folks living here in Minnesota land of ten thousand sloughs well some are lakes, I agree with most of the methods that have been discussed.

We have built several projects near the water table and I think the key here is that you place aggregate first, and build off of that with a drain tile slightly below the bottom of the footer. Vapor barrier below the slab and place the sump out side of the foundation.

First of all the aggregate acts as a storage chamber allowing fast coming water a place to go and will reduce some of the hydro on the concrete.

Second placing the drain tile above the lowest point well I probably do not have to explain that one it is so obvious.

Third I see the sump inside all the time and often wonder why anyone would invite the disaster inside the basement, that is a no brainer.

Another thing that I didn't see in the code, but know from older costruction and my neighbor's mistakes, is that any footing drain system should have a good upstream flush-out point. I even put one on my Form-a-drain system, since this system can't be easily snaked. Filter fabric is okay, but there's nothing like being able to snake a hose into the system from upstream. Seems like a good $15 investment for an elbow, a few feet of pipe, and an end cap at grade. I've flushed mine out already after one year and got a surprising amount of muddy water. Maybe it's construction dirt, maybe the fabric has a tear. Don't know and don't care. This will be a yearly maintenance item until I'm comfortable that it won't choke up in the future.

A perimiter drain is okay. A properly working one is great.

Mark

"Wicking" or capillary action is a function of pore size, amount of moisture at depth, pore pressure, humidity, etc. Comments by dmaceld are pretty much right on-but as Mark R. points out that it's pretty moot w/ ICFs. It's sealed in the foam unless it's really saturated.
But there are certain conditions (albeit rare) where moisture can be a little issue. If I were building a house with the footing in the water table, or high moisture behind a basement wall, I'd use 4000 pst concrete w/ 15% to 25% flyash...
But that's just me.

BTW, I'd NEVER bput any membrane between a footing and a wall.
JDC

"Rising Damp" or other terms is a real condition. You guys are just exposing your true ignorance and in some cases negligent ignorance. If you don't know about a topic, you are probably better off keeping out of the discussion. Europeans are way ahead of N. Americans when it comes to concrete and the inherent issues relating to the use of concrete in structures. I'd suggest some of you folks would do more for the advancement of the ICF industry if you would spend a little time reading and researching before acting like worldly experts on subjects that are obviously out of your league.

Ian, that was quite a "burn"
Enhancing your public image no doubt. LOL

Well, I don't know what Ian is mad about. The consensus pretty much arrived at is that wicking of water into concrete is reality. And youall are coming around to the idea of a vapor barrier under the footings, although aren't quite there yet.

And absolutely, any fabric or plastic break between footing and wall is a bad idea.

I think some of us recognize that Europeans are well ahead of us in sustainability and zero-energy buildings, and it would be helpful to know more about that, Ian.

I don't see it as a "burn"...if the shoe fits, wear it. I don't get mad about what gets posted here, I get amused! Every once in awhile when my email lights up with people asking me my thoughts on what people are saying on ICFWeb, I have to laugh at where some of these topics go. I also have to smile at the display of ignorance of some posters saying things such as earlier on this thread...to add to it, some people say they know nothing, then offer solutions or statements to refute what is already known.....this in my opinion is an "enhancement of public image"....reminds me of the spoof picture of Bill Clinton's face looking out of Al Gores A$$ that floated the internet a few years ago.

What does not bode well is when someone that posts frequently about topics and portrays themselves as an educated authority regarding issues, posts information that is blatantly incorrect and as an effect of such erroneous posts, causes potential ICF "consumers" to rethink using ICF.....A real disservice to the growth of the industry as a whole. I see it as carelessness. As a developer in NY told me, "with people like those on ICFWEB, they don't need anyone to slam the technology, they do a good job of destroying their chances without someone that objects to it (ICF)" All in all, the forum is a good thing, but as they say...."a few bad apples can destroy the bushel"

Lighten up dude.

What brand of "ego" did you have for breakfast ?

In the words of Wayne and Garth "we're not worthy!"

Ian........You did everything 'but' answer Quantum's question. What are your views on this situation??

Isn't the idea of "4000 pst concrete w/ 15% to 25% flyash" for footings a good solution? (like JDCPE said). Seems smart to try to reduce the pore size and increase the preasure.

I am not a builder, just a homeowner trying to design a very good house.

But what amazes me is the fact that such a basic topic like footings in high water table, affecting so many houses, is left to the personal experience of the builders, or to the different companies trying to sell their products.

I bought a book about ICF but couldn't find anything related there.

I'd be glad to see posted here links to books or independent researches that will answer this issue clearly, and their summarized conclusions.

For 4000psi all you're doing is adding more cement. It is overkill, and quite a bit more costly. 3000psi is way more than enough for 99% of homes when cured -properly-, which is rarely the case. Please see my article, "Concrete 201".

The best thing I can say is that the building crafts are very steeped in tradition. They are very slow to adopt new methods, as this imples risk. This is why adoption of ICF has been so slow.

Know that no concrete is going to reach its true maximum strength unless the hydration process completes. This will only happen with a slow, moist cure, where water evaporation is prevented for at least 28 days. However, almost without exception forms are stripped within 7 days of casting, releasing all that water, and flatwork almost never is covered with a blanket to hold in moisture. It's the way it is for alot of reasons, mostly economic.

But slow-cure is one reason why we use Fast Foot. When installed right it wraps the footer entirely, holding in the moisture for months, for a very good hydration of the mix, and a very hard footer. Thereafter the fabric deters water from wicking into the footer & foundation (as concrete is hydrophyllic), preventing that 'damp' feeling and concrete spalling for the lifetime of the house. ICF forms similarly hold in that moisture, giving the same benefits.

We recommend the max of 40% flyash because:

- it diverts this waste product from landfill;

- it replaces some of the cement, reducing the need for fuel to make;

- it actually -strengthens- the final product, over what it would be with no flyash, believe it or not.

A high percentage of flyash does make the concrete a little stickier and a little more difficult to finish, but hardly noticably, and this is irrelevant with ICF anyway.

Quantum, in your article you wrote:

"Concrete can be mixed with additives to make it completely waterproof. When designed, placed, and cured to industry guidelines, it requires no coatings or sealants of any kind. "

Can you please provide the names of these additives ?

Thanks!

Your local redimix supplier should have it as one of his admixes. Here it's called HydroMax, or somesuch. It was used in a Seattle Aquarium building which is completely submerged with no other waterproofing, and it does not leak. This stuff is great for rooftop patios.

Also might check the website for Mason's Supply here. They have two or three admixes, and can advise you.

I found Xypex Admix. It looks like a very good idea to use an admix with the concrete, to block the wicking and also against the corrosion of the rebar. I want to build a house for generations.  :-)

Frightfully expensive, but if you can afford it...