|
|
You are not authorized to post a reply.
|
 Prev Next
|
| Author |
Messages |
|
LARRY
Registered Users
Posts:123
 |
| 02/11/2002 7:58 AM |
|
This past weekend I cut out foam for electrical boxes on the first floor of a ranch house. After I removed the foam, the concrete was exposed. I couldn't believe it, but the concrete was actually wet. There were water droplets on the face of the concrete. You could moisten your fingertips simply by touching the concrete. Is this normal. If so, how long does it take the concrete to actually fully cure. It seems like all that moisture could possibly cause humdity problems for a while. The concrete was poured about 6 or 7 months ago.
....Larry |
|
|
|
|
|
|
Ian ICF Builders
Registered Users
Posts:612
|
| 02/11/2002 8:01 AM |
|
That is typical. The moisture will remain there until the relative humidity level on the outside of the foam is low enough to draw it out. Once the structure is finished and the interior space is conditioned, it will dry out over a period of time, but it will never get 100% "dry" as long as the foam is on it.
|
|
|
|
|
Unregistered
Registered Users
Posts:2321
|
| 02/12/2002 8:43 AM |
|
| THAT IS SCARY |
|
|
|
|
Rick
Registered Users
Posts:157
|
| 02/12/2002 9:19 AM |
|
| Fear not, Paula. Every type of material used to build your home, concrete or wood, will have a certain amount of moisture in it. It is minute in most cases, and only detectable with sensitive testing equipment.Nothing to worry about. |
|
|
|
|
Ian ICF Builders
Registered Users
Posts:612
|
| 02/12/2002 9:28 AM |
|
To add to Rick's comment, in wood frame construction, a similar event must take place...the moisture content of wood framing members must move to equilibrium (just as in ICF). In wood frame construction, you will notice this transition via cracks and nail pops in drywall, shrinkage of wood trim and what appears as caulk shrinkage. The beauty of ICF is that the EPS and concrete don't exhibit these signs of shrinkage, so you shouldn't notice the drywall cracks etc. at least on the exterior (ICF) walls. Furthermore, in wood frame construction, there is a cavity that is open where the moisture will move to....this cavity is a great place for mold and mildew, critters and bugs to call "home". The cavity that may be conducive to mold and bugs is supposed to have either fiberglass or cellulose insulation in it. If moisture is moving around the insulation, then the effectiveness of the insulation is less than what you think it should be. With ICF, none of these issues are a concern....
|
|
|
|
|
enermizermuskoka
Registered Users
Posts:272
|
| 02/12/2002 3:21 PM |
|
...Furthermore and I quote "all wood products
used in construction are subject to decay if
allowed to remain wet for periods". Even kiln
dried lumber(moisture 19% or less) can absorb
water by acting like a sponge on hot humid days, thus defeating the premium price & purpose. If you look hard at any piece of
dimensional lumber, you will find some inherent charactoristics susceptable to decay
-But enough of that, why even compare.
Larry,I recall a post about fog on windows.
I.C.F.'s provide a "wet" cure, thus providing a stronger concrete than the "traditional" pour and strip the next day
methods used. Rest assured, I'm guessing that your home is on the way to lasting a very long time. Take-care, Sincerely. C.Kerr |
|
|
|
|
IConForm
Registered Users
Posts:22
|
| 02/13/2002 12:12 AM |
|
Larry - I think the moisture you are observing is a good thing, as enermizermuskoka points out a wet cure greatly assists the concrete to reach a given strength quickly, one of the many benefits of ICF over conventional forms. Also - depending on your soil conditions, the moisture in the concrete can be maintained partially by wick-effect from the ground up through the footings, unless a barrier was placed specifically to retard this.
Also, unless the concrete was (no heat yet?)cold and the moisture is condensation from the moist interior of the building when you cut the foam away, I'd say that you have pretty convincing evidence of the efficacy of foam as a vapour barrier.
You ask "how long does it take the concrete to actually fully cure." Essentially, under the proper (moist) conditions concrete never stops curing (hardening); it just gradually slows down. Allowing regular concrete to freeze at too early a stage will, however irreversably halt hydration to such a degree that no amount of moisture added later will allow it to harden, ever.
The psi strength of concrete as you order it is calculated at 28 days (or 30, I forget which) on a purely arbitrary basis. It's merely a practical time to wait for a practical strength to make the measurement. A year after that it will be stronger, and two years after that it will be stronger again. In the absence of water it will slow, but when moisture is again present it will continue hardening again (except if it's been frozen at an early stage.)
Hope this helps.
|
|
|
|
|
markross
Registered Users
Posts:1035
|
| 02/14/2002 10:57 PM |
|
What is it with this wick effect. I have been reading this time and again that "wicking" of concrete represents moisture collections and problems in many areas of the home. NO IT DOES NOT. there is a moisture content in the concrete which will raise if a portion is exposed to water, but the concrete will only allow water to within itself through capillary action mostly, and off gas's the rest. Concrete does not "pump" the water up the wall to thease locations, covered or not. I have spoken with Larry several times, and I know that he has a very high humidity in his home, as there is plastic on the cieling truss's and no ventillation, it stays closed up most of the time. More than likely, the concrete is acting as an effictive vapour barrier, and the moisture is collecting on the surface of it, by finding its way through the cracks in the block, or it was caught in the block at the joints as free water during the pour, and has been trapped in there due to high humidity ever sense. I know the block that he used, and it is prone to a small amount of shrinkage over even a long period of time, and I would bet that there are 1/16" gaps in the horizontal joints, through which the humidity can access the wall and collect, as there is not cover on it, and it has been poured for a rather long time now. I applaud Larry as he has done his project himself, and successfull at that, mostly with the insight he has gained from this forum. You all have a great knowledge, and Larry is proof that this forum helps people. However, lets not start scaring people. What if the water is from the vapour barrier condensation, running accross the cieling, to the wall and then flowing between the foam and concrete surfaces, due to the very slight concrete shrinkage as it is curing. Maybe the block has poured to compress so tight as to effectively seal the joints, and the water is simply collecting in the space. In any case, as soon as he fires up his HVAC system, which I know what it is, he will have any current and future humidity and moisture problems such as this solved.
Have a good night.
Mark Ross
"Le Canuck" |
|
|
|
|
IConForm
Registered Users
Posts:22
|
| 02/17/2002 12:44 AM |
|
Mark - you wrote "What is it with this wick effect. I have been reading this time and again that "wicking" of concrete represents moisture collections and problems in many areas of the home" . Your use of the word "again" implies that you read it here in this string - NO YOU DID NOT! What you did read is exactly this;
"Also - depending on your soil conditions, the moisture in the concrete can be maintained partially by wick-effect from the ground up through the footings, unless a barrier was placed specifically to retard this." and nothing more.
The capillary rise which results from the porousity of concrete which you describe is precisely what I was referring to, and nothing more. Eventually that moisture condition will reach a steady-state equilibrium where all ingoing and outgoing moisture will stabilize in the wall, depending on ambient conditions (which the HVAC will change for the drier). In my eyes we are saying the same thing. ie. Larry's observation is of a normal condition, and NOT a "problem",(neither "currently" nor in the "future".)
Hope this wasn't too scary for anybody, that wasn't my intent.
Regards - Brian
ps. now I'm curious Mark, where did you read that concrete "pumps" the water to cause moisture collections and problem areas in a home?
|
|
|
|
|
markross
Registered Users
Posts:1035
|
| 02/17/2002 1:54 AM |
|
Iconform:
"ps. now I'm curious Mark, where did you read that concrete "pumps" the water to cause moisture collections and problem areas in a home? "
Within this website, actually one just passed on this topic, someone advised this exact poster, that one of the possibilities of the condensation on his windows was the result of water wicking around the opening. The pumping came from a post about 10 months ago.
What concerns me is that I read time and again people posting information stated as fact. I recognize that people make mistakes, and I do a lot of them here as well. Ian, Mr. Juan and several others have corrected me, and I sheepishly thank them. It is not my intent to mislead anyone, however, if I am wrong, at least I post an apology and admit it so that the original poster understands my err and gleans the proper information. However, when I read about wicking, it concerns me. First off, this is not an exposed concrete wall. And yes a typical concrete wall will have about 30% free Portland which does not cure due to lack of H2O and other reasons, however, in an icf wall, there is a substantial decrease in the amount of free Portland and water. Also, the cure is much different, creating a tighter knit chemical bond, which helps to slow down the transfer of water molecules, not increase it. It just frustrates me sometimes to see situations such as this happen time and again.
I apologize for the confusion, and forcing you to listen to my ranting.
Mark Ross
"Le Canuck" |
|
|
|
|
Unregistered
Registered Users
Posts:2321
|
| 02/17/2002 7:40 PM |
|
Forgive me for ignorance - jumping into the deep end of the ICF arena....
If:
1) an ICF wall is poured
2) a *good* vapor barrier is competently and carefully installed under the sheetrock on the interior face of the ICF
It would seem that the water that Larry found when installing the outlets would be 'trapped' between the vapor barrier and the concrete - or between the interior EPS and the conrete. At any rate, it would seem that this trapped moisture could result in molds, mildews, or other less than favorable things.
Wouldn't this be the case? Operation of the interior HVAC wouldn't eliminate this - once that vapor barrier is installed. No matter how warm it gets, that water will be stuck under the barrier, right?
Thanks for entertaining my post. I appreciate this forum and the info shared by all!
|
|
|
|
|
Unregistered
Registered Users
Posts:2321
|
| 02/17/2002 7:54 PM |
|
One other thought -
Couldn't this pose problems for any metal electrical components installed in this case? I'm not sure I like having boxes installed on a surface that has the potential to stay wet indefinitely (if in fact it does). |
|
|
|
|
OKBlocker
Registered Users
Posts:635
|
| 02/17/2002 10:01 PM |
|
Keith,
No one in my area installs a moisture barrier behind the sheet rock. Why would you need too? |
|
|
|
|
Unregistered
Registered Users
Posts:2321
|
| 02/17/2002 11:07 PM |
|
Granted, the vapor barrier behind the sheetrock is a 'throwback' to stick-nuilt methods. But it still seems that you would want to stop all vapor from traveling into the wall - where it could eventually encounter a (relatively) cold material...then condensation occurs. A vapor barrier beneath the rock will keep the warm, moist (again, relatively speaking) air from reaching cooler materials (the rock will be at the same temp as the interior air....as it is fully inside the insulated envelope).
I'm also curious - one post in this thread says that the presence of the water is evidence of EPS as an effective vapor barrier...but another notes that this form type commonly has 1/16" horizontal gaps - which would obviously make the interior wall of the form a very poor vapor barrier.
If the water Larry found behind the EPS is due to water vapor condensing on the inside of the concrete then that would be of concern to me - water in that 'space' would undoubtedly lead to something growing in there. Mind you my frame of reference is the bitterly cold northern plains.
Does my logic make any sense - on either item? :o)
Thanks again - |
|
|
|
|
markross
Registered Users
Posts:1035
|
| 02/18/2002 12:17 AM |
|
Kieth:
first, the 1/16 gap pertains specifically to the product he used, not ICF's in general. Also, with this gap, there is an avenue for this free liquid to escape. I have yet to encounter a problem, in many years of ICF construction associated with water condensing in the wall cavity. Most often the dew point is within the concrete, or in the exterior foam, which tends to solve the problem, as there is no place for it to condense. Free water such as what larry has is due to the method in which he is building his home, that is all. It would happen with any type of construction, wood frame, block or otherwise. Mind you, the ICF is a saving grace in this case, as the extreamly high humidity levels will disapear after completion and occupancy.
Mark Ross
"Le Canuck" |
|
|
|
|
Ian ICF Builders
Registered Users
Posts:612
|
| 02/18/2002 8:09 AM |
|
Mark:
C'mon, the "gaps" are not specific to one brand of block. the gaps are present in all of them....90% of the ICF production is done with the same equipment and the same raw material...all molded EPS blocks react similarly.
When we built in Alaska, the addition of a poly vapor barrier on top of the EPS vapor barrier was a code requirement unless an additional 1"+ of foam was to be added to the exterior of the wall...which would essentially move the dew point to the exterior. Greenblock and Quad-Lock are the only brands of ICF that have addressed this by making a product with thicker exterior EPS shell dimensions. One thing I noticed is that the poly vapor barrier went on well before the structure could possibly have reached an equilibrium...so Keith, your concerns are valid but remember the alkalinity of the concrete and the fact that there truly is no "air" between the foam and concrete that would be conducive to any type of growth to consume the structure. In contrast, I built my father's basement about 12 years ago, when some remodel work was being done, the concrete was exposed for some electrical...the concrete was black but didn't show free moisture....it was damp obviously since the "blackness" turned to "grey" after exposure to the room....so maybe you have something here, but once again, I think the ICF is being scrutinized beyond the norm....It is still far better than sticks and bricks.
|
|
|
|
|
markross
Registered Users
Posts:1035
|
| 02/18/2002 10:51 AM |
|
Ian:
Not the brand but the "product" (It was a time cured eps foam block manufactured at the height of the building season). The prossess is not always the same, manufacturers of blocks such as Integraspec use an oven curing post processing which helps significantly with the dimensional stability. Other manufacturers hold stock to allow for "drying" (for lack of a better word)and these as will tend to reduce or eliminate the gaps. I have noticed it is usually panel systems such as formtech or eco-block, (although during busy seasons they can become the same as well). Block size has a big impact as well. Although the overall total shrink factor may be the same, the little blocks tend to reduce the effects, probably due to the increased proximity and number of joints. The size and type of bead, used in the process, the density of the bead, and percentage of re-grind (if any) has an impact, for the process can extend or reduce the length of time it would take to reach 99% dimensional curing shrinkage. One of our guys, recieved a load of block which was manufactured three days prior to shipping, installed in one week, and four weeks later left 1/8" gaps at every horizontal and vertical joint throughout the building. I had to go back and foam in every joint (whew what a task). Lets say I learned a lot over the next month or so, as I did not want it to happen again.
Mark Ross
"Le Canuck" |
|
|
|
|
Unregistered
Registered Users
Posts:2321
|
| 02/18/2002 12:53 PM |
|
Ian,
I agree that ICFs are being scrutinized beyond the norm - but this should be expected by anything that runs counter to anything we (as a society) consider 'normal'. When the 'horseless carriage' was introduced the big fear was that it would scare the horses. (I'm guessing here! :o))...No one was bothered that the existing horses weren't scrutinized for their ability to scare other horses! ;o)
At any rate to continue the discussion....(personally) I don't think the alkalinity of the concrete will retard growth of organisms - we see molds/mildews/mosses/etc growing on concrete everywhere (albeit, these aren't sealed conditions). Organisms have been found living in some incredibly nasty places (e.g., boiling sulfur mud pits in Yellowstone) so I'm guessing the potential exists in this case. I also believe that there is enough 'air' between the concrete and the EPS to support these critters.
I agree that nothing will grow that can 'consume the structure' - afterall, it's concrete! but it could still lead to foul smelling air that may or may not present risks to humans (the jury is probably still WAY out on that one!).
Finally, if the EPS does act as a vapor barrier on the EXTerior - you could potentially have condensation at the interface between the outside of the concrete and the exterior EPS - which would be outside the HVAC conditioned air. This would also be under any EIFS finish such as GrailCoat or Permacrete. In stick building there is no exterior vapor barrier that could 'trap' the moisture. And the ramifications of THAT...we can argue ad nauseum!!
The black on the surface of your folks' house makes me wonder though. Granted none of this is a whole lot different than applying EPS sheets to a normal, freshly poured basement wall - some moisture could be trapped there as well. It just seems that were talking about a much more 'sealed' or out of sight situation with our ICF products.
Another dose of my 2 cents...probably worht much less than that! :o)
|
|
|
|
|
markross
Registered Users
Posts:1035
|
| 02/18/2002 7:22 PM |
|
quote:
Organisms have been found living in some incredibly nasty places (e.g., boiling sulfur mud pits in Yellowstone) so I'm guessing the potential exists in this case. I also believe that there is enough 'air' between the concrete and the EPS to support these critters.
I agree that nothing will grow that can 'consume the structure' - afterall, it's concrete! but it could still lead to foul smelling air that may or may not present risks to humans (the jury is probably still WAY out on that one!).
Keith:
Ther is no reason, and I mean no reason for ICF structures to have a mold problem. I have yet to have such a problem, and our guys dont have them anymore either. The key is in how you handle your independant heating, ventillation and air conditioning systems. It is not a normal structure, so there are key design considerations to take into account.
I recomment our info course on this. its march 18th to 20th, and we will be covering a lot of this, and topics like this. goto www.arit.com or call 1-877-278-8802, and Nick will hook you up.
Mold and mildew need never be a problem in your ICF home, all you need to do is handle the indoor climate properly.
Mark Ross
"Le Canuck" |
|
|
|
|
|
| You are not authorized to post a reply. |
|
|
|
ActiveForums 3.6
|
Professionals Serving
Your Location:
GBT Project Albums:
|