First time with ICF
I have to offer exterior siding options on a building .
Basic construction is ICF.
1) Metal (similar to Valrib or a rib and flat pattern)
2) Hardie plank style material
3) Nichia Shake (Hardie like mat. in sidewall shake pattern)
Question:
1)Is there a need for strapping under each of these on ICF?
2)Is there a need for moisture barrier under each of these on ICF.
I talked to buddy who is a BI and he told me on his own ICF building he refused to use the moisture barrier because the dew point occurs with the ICF and he wanted the wall to dry to the outside.
Edited 9/26/2008 9:42 pm by dovetail97128
Replies
here VB isn't used...
strapping is... 12"OC..
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!
The thing to watch out for with ICF's is they won't and can't be as straight as a stick framed wall--it's simply the nature of the beast. Even if walls are string lined and walls are plumb, corners or some random sections may have slight bulges of 1/4" or more. If a wall is plumb a corner may be in or out quite a bit. Plumbing walls after a pour is easy, making corners move is very hard.
I pour walls as straght as possible, but many contractors have snakey walls that are so bad I can't imagine having to side over them without strapping.
Plan on strapping or at the very least careful shimming if the walls are straighter so the variations don't telegraph.
If you are deciding between contractors to pour the walls, make sure you see their past work before it's covered up and put a straight edge to the corners.
No exterior moisture barrier is typically used since the foam and concrete take care of that.
Beer was created so carpenters wouldn't rule the world.
IdahoDon
I suspect that has more to do with the blocks used than skill of the contractor..
My walls are flat as a pancake and they were laid by my sister-in-law with a 20 minute drug slurred instructions..
I screwed sheet rock directly to them and it wound up nice and flat.
The scaffolding they provided acts as a means to keep the walls straight.
Other homes made with the same blocks sure look nice and straight.
ICF's are well known to suffer from poor straightness if the contractor isn't careful. It's just the way it is. Ask most pump operators and they'll tell story after story of the same.
Beer was created so carpenters wouldn't rule the world.
IdahoDon
With no experiance at all my walls wound up nice and straight. Now granted the pump operator had probably poured hundreds of walls and was carefull to tell us how to do it but when I put sheetrock on the inside of my walls the sheetrock laid nice and flat. The outside appeared nice and straight when I back filled it.. When I put the top plate on I saw no wavyness.
To be fair I didn't set the wall, My sister-in-law did. Her only prior construction experiance was painting her bedroom.. I started the first layer and a half then went out of town in a new car as a result I became bedridden due to a bad back.. I'd given her a 20 minute drug slurred instructions before falling to sleep.. The next day With a tender back I set the scaffolding up and with it the braces that aligned the wall..
I can't explain my success with your experiance. Maybe it was a differance in the forms? Maybe the pump operator's experiance made the differance, I don't know..
I do know the brand of ICF I used is common here and I can take you to several all ICF homes with walls that appear nice and straight.
"I talked to buddy who is a BI and he told me on his own ICF building he refused to use the moisture barrier because the dew point occurs with the ICF and he wanted the wall to dry to the outside."
When you say "moisture barrier", what are you referring to? I would not want a "barrier" on my home either in your climate, but I would want "weather resistive barrier". Maybe it's just semantics.
If you use #15 felt (or Grade D building paper) or Tyvek I don't think you would have any problems. You will have very little air infiltration with a properly detailed ICF shell, so the ability for bulk water to be transported through the wall assembly is almost nil. Any diffusion will not be hindered by felt or Tyvek, which have perm ratings of close to 60 when wet.
Edit: What kind of ICF will be used? Is it made of XPS or EPS foam?
Jon Blakemore
RappahannockINC.com Fredericksburg, VA
Edited 9/27/2008 4:49 pm ET by JonBlakemore
and he wanted the wall to dry to the outside
There is a lot of moisture in the ICF walls for the first year. I read a case study somewhere, but can't remember the source or even the results, other than I was surprised how well the foam holds the moisture from the original concrete pour.
Interior moisture has a hard time getting through the interior ICF foam, so that is almost negligible compared to the moisture up front.
Beer was created so carpenters wouldn't rule the world.
dovetail
Have you looked at stucco?
Not real stucco but the stuff that's applied by smearing it on the wall that's made for application on foam.. There are a lot of commercail building that use it plus more than a few private dwellings..
You won't have the same rot issues with it that you will with stick framed homes because of a lack of wood.
synthetic stucco use here will exceed the budget.
Already looked into it.
They can't get your Goat if you don't tell them where it is hidden.
dovetail
I'm surprised!
It was really cheap here when I looked into it.. Could you have been given a high price by someone not eager to do the work?
With those products, no to strapping unless wall isn't straight.
ICF walls need no moisture barrier.
Oh, and I wouldn't use synthetic stucco directly on the foam at any cost.
'Me not built for pretty - Me built for strong' TM
It is State Law here that synthetic stucco cannot be used unless it is done using a moisture barrier,which adds about $28,000 to the estimate.
That option becomes so expensive as a result that it is out of the question because of budget considerations. Well that is unless the owners want to kick in another $28,000.00 I offered it to them anyway , but only as a test of their "ethics" since they told me that the budget/loan amount was a hard ceiling number and if I couldn't hit the budget number then the building wouldn't be built.
Always good to know in the beginning if the owners want to play money games.
Edited 9/28/2008 9:57 am by dovetail97128
What do you mean by "moisture barrier"?
Jon Blakemore RappahannockINC.com Fredericksburg, VA
""What do you mean by "moisture barrier"?"" Semantics IMO Felt, Building Wrap, Tyvek, Typar, "Weather Barrier", or whatever else you wish to call it.
Not a vapor barrier, a moisture barrier. Not a wind or infiltration barrier a moisture barrier. From what my BI has told me here they do not consider synthetic stucco to stop moisture penetration and therefore a "Moisture Barrier" is mandatory (Same rule applies to wood framed buildings) . This issue came up when the original specs for the job called for a synthetic stucco without a moisture barrier under it and I had to have the specs re-written to meet code here. I contacted the synthetic stucco manufacturer and they declined to fight the ruling.
I am not going to fight the State of Ore. on this. ICF is most likely PolySteel, possibly Formtech
http://www.polysteel.com/
http://www.pacificnorthwesticf.com/formtech.htm Both products are EPS PolySteel has recently merged with Arrx
http://www.polysteel.com/press_release.html
They can't get your Goat if you don't tell them where it is hidden.
We have used a exterior coating from Conproco that applies with either roller or spray system over stucco, synthetic or masonry. It is a polymer type coating that is water tight and flexible, almost rubber like. It comes in many colors and seems about as water tight of a system you could come up with. Much more so than any siding over wood frame system I'm aware of. Attention to detail at penetrations would be main spots of concern, same as most systems. All together, this should be a fairly reasonable alternative, cost wise. Of course, if no one in the area is familiar with it, that may drive prices up beyond the norm.I'm not sure if Nudura is available in your area, but if so, check it out. We have used many brands of ICF's including polysteel and Arrx, and Nudura is the best so far. 8' x 18" high blocks that give fewer joints for size of wall, they actually click lock together, corners are reversible, etc. 6 courses of Nudura equals a 9' high wall vs 8' for most brands.
Thanks for the Conproco info. I book marked it for review, I may have a need of some of their products anyway. Nudura website doesn't list a distributors list so I have no idea if it as available here.
I am already deep into this with the two previously listed suppliers and once I move( within a few days hopefully) I want ICF people onsite within a week from start date.Foundation is already in place and ready to go so that precludes a lot more investigation into suppliers and erectors.
They can't get your Goat if you don't tell them where it is hidden.
It seems to me that the state is asking for a water-managed EIFS system as opposed to a barrier system. If my assumption is correct, than I would agree with them.Is the reason that synthetic stucco is $28k more because the sub would have to install a moisture barrier, more EPS, then the stucco?Regardless, my big concern with no moisture barrier (with any type of exterior cladding) would be how would you flash your windows, doors, and other penetrations? If you have Tyvek or felt installed in shingle fashion, you can easily integrate your flashing with the moisture barrier. If you did not have a moisture barrier, would you just caulk behind the nail flange of the windows, or what?
Jon Blakemore RappahannockINC.com Fredericksburg, VA
According to the ICF sub it is flash the area around window and door bucks and leave it at that . His claim is no moisture will make it all the way through the ICF completed system.
That is something I 1) don't really believe, 2) runs counter to what I have read and 3) seems to go against the rules here. I posted my question to hear what others would do , or have done or think is best practice.
They can't get your Goat if you don't tell them where it is hidden.
dovetail
The only leakage I've ever seen thru a ICF form was when it was placed in a area of known water (underground spring) without any waterproofing then buried..
The solution was to dig out the back fill, add drainage pipe, water proof the wall and back fill again.. everything that should have done prior to back fill.
In my case My portical doesn't have any exterior water proofing (it does have drain pipe) and in spite of extremely heavy watering due to a new lawn and garden it hasn't leaked a single drop.
This is a curved wall where each block was sawn into three parts and glued back to gether with spray foam..
IN short the idea of waterproofing an ICF wall makes about as much sense as waterproofing a rain coat..
Water won't migrate through the stucco, through the foam, through the concrete and back thru the foam again. It can't! there is no pressure driving it as there was in the case where it was leaking under backfill. (don't forget each seam is spray foamed together on the inside)
Edited 9/28/2008 7:23 pm ET by frenchy
"Barrier System" is that the terms of synthetic diectly over a substrata? No rain screen is needed here, just a moisture barrier. The costs goes up because the synthetic cannot be simply applied to the ICF , it requires a moisture barrier , then a lath (expanded Metal) then the stucco in scratch and brown + finish coat.
They can't get your Goat if you don't tell them where it is hidden.
What I've seen described as the "barrier" system was basically stucco applied with no regard to a secondary drainage plane.The assumption was that the stucco was watertight, and you didn't have to worry about water management past that outer barrier. The issue came about when you get one little crack in the "water tight" barrier. Now you have a situation where wetting can occur but drying cannot. In other words, really nasty stuff.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
I wonder if there is a misinterpretation of a law on this subject. Nudura, a manufacturer of ICF's, calls for direct installation of synthetic stucco to the surface. There is no sense in a moisture barrier between the foam and stucco, only between stucco system {foam} and wood framing. This is a common installation detail all over the country, even done south where most issues have been with dryvitt type systems.
State Law, passed by the legislature. Not even a matter of the Building Code here. No misinterpretation at all.
It is what it is.
I am not fighting the State on this one.
They can't get your Goat if you don't tell them where it is hidden.
"State Law, passed by the legislature. Not even a matter of the Building Code here."Do you have a citation or reference on that? I just did an Internet search and all I could find was that a bill was introduced in the Oregon Senate in 2007 as SB980. It directed the Director of Department of Consumer and Business Services to draw up requirements to amend state building code to prohibit installation of synthetic stucco in residential structures. It was referred to committee. I cannot find that it got out of committee or was passed or that there was a comparable House bill. I did find several references to buildings in Oregon that were constructed with ICFs and had stucco exteriors.
I will have to get a copy of the notice posted at the local county building/planning office concerning it. I had a copy here in my stuff but don't see it right now. It is that notice that set me off in search of answers and the first person I talked to was the County Building Official.
He is a friend as well as a very sharp man. He went to bat for me in terms of checking out the exact rules, he went so far as to ask the State Board that handles such ruling and came back to me with a firm "NO".
They can't get your Goat if you don't tell them where it is hidden.
Well, it's obvious that the state has thrown the baby out with the bathwater on this one. As others have pointed out, there is no need for a moisture barrier on a foam over concrete wall. But, if you can't fight city hall, then you have to look at other alternatives.
Here is my take on the stucco issue anyway: I would not stucco directly over the foam with any kind of color coat, I would always do the lath and brown and color (either traditional or synthetic). One of the first jobs I did as a licensed contractor was to repair a vacation home that was a color coat- over 2" foam board- over frame that was riddled with bird holes. The birds had no trouble pecking out nests through the color coat and were happily living in the foam.
Think of other things, like an errant baseball, or a lawnmower, or a shovel handle falling over. These would be expensive repairs, if done to undetectable levels.
Granted that the foam blocks are firmer than the bead board in the example, I still wouldn't count on a color coat only to protect the outside of an ICF home.
So if stucco is the desired look, there is no cost savings due to it being of ICF construction, in other words, it will cost what it would cost to do a conventional home. At least that's the way I do it.
'Me not built for pretty - Me built for strong' TM
When you say no to synthetic stucco, I'm curious, why exactly is that? In a typical Dryvitt installation, isn't that how it would be applied? I believe most ICF manufacturers allow this as a approved finish.
I explained in my reply to dovetail why I don't like synthetic directly over foam, even if it is done all the time, and is an approved ICF finish.
'Me not built for pretty - Me built for strong' TM