Thread: Stucco over Insulated Concrete Forms (ICF) walls

This is a relative new one on me. Let me set up the senerio:
3 yr old 4900 sq. ft home in S. Texas. Several Builders in this upscale development are using a ICF (concrete) wall systems. Having experience inspecting wood frame stucco homes my eyes are keyed into staining as an indicator of possible water intrusion behind the stucco.

So....I see staining (possible efflorence?) in several suspicious areas (at least by wood frame standards) including roof/wall transitions. I get my moisture meter out and indicate near saturation moisture levels (in penetrating mode) on all stains. I have been on the ICF assoc. website ( Building Inspector) and see that generally a WRB is not required between the stucco and ICF. However, some of the moisture encountered would be at the roof to wall transition where there could be wood framing or substrate. No interior moisture indications are present. There is some staining on the end of a valley rafter where I have staining. Drain (weep) hloes are present at the base of the ICF like you would see in a masonary (stone or brick) veneer.

Any assistance or knowledge of this type of wall system and stucco wall covering would be appreciated.


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ICF or not, you still need to have the proper details. It looks like they did not place any diverter flashing at the picture with the rain gutter. This is why you have that stain running down the wall. Granted it is a concrete wall, you still don't want water running down it. Did you see any flasing at the roof to wall joinings?

The section at the second floor with the stone like details; this is just a screwy design. I don't know what can be done to solve that problem.

The wet rafter; screwed up valley?

Scott: Yes, it actually did have good roof to wall flashings, kick-outs, detais, etc. One or more kick out were altered (smooshed) by the gutter installation.

My Wood Frame Stucco mind says that there are water intrusion issues that may not be readily evident (at this time) and the stained valley rafter appears to be the tip of the smoking gun I was looking for.

The kicker is that the ICF website says that WRB's are not required which would mean to me that any amount of water on this wall would be acceptable. However, there has to be a wood framing/substrate connection where the ICF ends. This is my real concern. We all know the stucco is NOT water proof no matter how much elastomeric paint we put on it.

I will for sure be recommending further eval but I also need to back up WHY I am recommending eval.

Thanks for the opinions. This is a great resource for us lowly inspectors

Originally Posted by Rod Stewardson

Scott: Yes, it actually did have good roof to wall flashings, kick-outs, detais, etc. One or more kick out were altered (smooshed) by the gutter installation.

My Wood Frame Stucco mind says that there are water intrusion issues that may not be readily evident (at this time) and the stained valley rafter appears to be the tip of the smoking gun I was looking for.

The kicker is that the ICF website says that WRB's are not required which would mean to me that any amount of water on this wall would be acceptable. However, there has to be a wood framing/substrate connection where the ICF ends. This is my real concern. We all know the stucco is NOT water proof no matter how much elastomeric paint we put on it.

I will for sure be recommending further eval but I also need to back up WHY I am recommending eval.

Thanks for the opinions. This is a great resource for us lowly inspectors

Is it "real" stucco with lath, etc.. or is it just a stucco like smear coat on the concrete wall? It looks like it is just a finish coat on the concrete wall.

Originally Posted by Scott Patterson

ICF or not, you still need to have the proper details. It looks like they did not place any diverter flashing at the picture with the rain gutter.

Originally Posted by Rod Stewardson

Scott: Yes, it actually did have good roof to wall flashings, kick-outs, detais, etc.

Rod,

In the photo Scott referred to, the stucco looks like it goes almost all the way down to the roof covering, which is not correct if that is the way it is - should be at least 2" clearance.

One problem I see in that same photo is the front wall which is bumped out leaving a flat top area.

That flat top area IS A ROOF but is never treated as a roof. At the very least a full flashing needs to extend from the back wall, under the stone, and over the edge of the front wall, with a drip edge. I don't see a drip edge there. Think of that as needing the same thing a brick veneer wall needs - a through the wall flashing from the back and extending out to the front.

Staining at the gutter is really nothing as the gutter could be overflowing, however, you also see staining under the soffit, and that is a problem.

Another thing is how they did the stucco - many times they simply stucco over the ICF forms, with no place for the flashings to actually get behind the drainage plane as they do not have a drainage plane.

I have not seen many (just a couple) of ICF homes, but each was just stuccoed over the ICF and left much to be desired about flashing techniques.

Originally Posted by Scott Patterson

Is it "real" stucco with lath, etc.. or is it just a stucco like smear coat on the concrete wall? It looks like it is just a finish coat on the concrete wall.

Scott,

ICF homes do not have a concrete wall to stucco over, they have an exterior of foam (think like EIFS) which gets stuccoed over.

The concrete wall is between two layers of that foam, the foam is just the left-in-place-form the concrete is placed in.

Scott: This is real stucco. Very thick in fact.

JP: The "bump out" is actually the end of the one story ICF wall and the start of the second story wood framed wall. This is why I am so concerned about the typical stucco water intrusion in these areas. It appears that this ICF mfg (i dont know which one yet) requires drain hole at the bottom of the wall much like brick or stone veneer. This likey is to drain any water that would enter from the mortar cap at the bump out, run down the EPS foam?? and out the weep. Seems like to much monkey motion to me instead of just flashing the top and be done with it.

Originally Posted by Jerry Peck

Scott,

ICF homes do not have a concrete wall to stucco over, they have an exterior of foam (think like EIFS) which gets stuccoed over.

The concrete wall is between two layers of that foam, the foam is just the left-in-place-form the concrete is placed in.

Ooops, I had a brain fart. I was thinking of a poured concrete wall for some reason. Thanks!

Need more coffee.........

Originally Posted by Rod Stewardson

It appears that this ICF mfg (i dont know which one yet) requires drain hole at the bottom of the wall much like brick or stone veneer. This likey is to drain any water that would enter from the mortar cap at the bump out, run down the EPS foam?? and out the weep. Seems like to much monkey motion to me instead of just flashing the top and be done with it.

I have not heard that one.

Sounds bogus to me.

A brick wall has an air gap which water is designed and intended to weep down, the weep holes are there to allow that water to weep out.

ICF has no gaps or air space, and if it does, the concrete was not consolidated and re-consolidated as required, and there is no air space between the wall finish and the foam of the ICF blocks - meaning there is no drainage plane (no intentional drainage plane) which is what makes flashing them a problem. About the only way I can see flashing them would be to cut a groove and insert the flashing into the foam, similar to what would be done when flashing a brick chimney. That would allow the water at the foam and at the surface of the stucco to *not get behind* the flashing and then allow the flashing to direct the water out where the flashing takes it.

No cap flashing on that bump out wall would be like building a wall with a parapet and *not* installing a parapet wall cap flashing (coping) over the top of the parapet wall - JUST PLAIN DUMB!

Let me understand this: the first story is ICF, the second is frame, the front has a bump out wall for the ICF but the side does not?

What made them change methods?

Additionally, the stucco on frame wall at the second story now REQUIRES weep screeds where it meets the ICF below it.

THAT is likely where the problem is - water WILL get behind the stucco on the second floor, that water is REQUIRED to have a way out - weep screeds, without that way out, the water will not have choices on where to go along the top of the ICF wall ... inside, outside, down into the wall, back into the open area at the roof, ... use your imagination, the water will, and it will not only go the easiest route but some will go where you least expect it.

That stucco on frame second story requires, and needs, weep screeds all along where it meets the ICF below ESPECIALLY AT that bump out wall.

I totally agree about the weeps being bogus but they were there in many paces. Where is the water coming from to drain out of the weep.

You are right, they changed their method in the back of the house as oposed to the front and sides. I hadn't given that much thought.

I agree with the weep screeds as well. Check out the sealant job some one installed at the roof to wall transition where I have staining. Some one KNOWS about this problem and TRIED to "FIX" it with sealant.

Check out out the additional pics of the weeps and sealant.

Originally Posted by Rod Stewardson

I totally agree about the weeps being bogus but they were there in many paces. Where is the water coming from to drain out of the weep.

Those are not construction made weeps, those are where someone said 'Looks like a good spot ... right about here ... to drain that water.'

I agree with the weep screeds as well. Check out the sealant job some one installed at the roof to wall transition where I have staining. Some one KNOWS about this problem and TRIED to "FIX" it with sealant.

That TOTALLY sealed up any weep screed if one was even installed. They simply took a problem and made it worse!

Thanks for all of the opinions.

Originally Posted by Rod Stewardson

I have been on the ICF assoc. website ( Building Inspector) and see that generally a WRB is not required between the stucco and ICF.

Maybe ignore the ICF requirements and focus on standard stucco requirements for drainage, flashing and WRB. It seems the ICF requirements are a red herring in this case since these folks are only concerned with the wall structure and likely will defer to the stucco or finish system requirements for water proofing.
If this was EIFS it is face sealed but traditional stucco still requires flashing and WRB no matter what it is applied over.

I agree but it is hard to ignore that one of the "selling" points from the ICF assoc website is:

Weather Resistant Barriers are no longer required for above grade ICFs, per the changes in the 2006 IRC, however local conditions and some materials may benefit from additional protection from driving rain and extreme weather. Waterproofing or dampproofing remains a requirement below grade, same as any concrete foundation wall.

Application of traditional stucco finish over ICFs remain a popular and cost-effective finish. For further application information, refer to the PCA website: PCA - The Portland Cement Association for the FAQ on Stucco

I dont know anywhere in the code that it says a wrb is not required with ICF. If there is a req then it would be hard for me to say that one should be there.

I am more concerned about leakage at the wood frame connection to the ICF. I bet a IR would light up at this house. Does any one close to SA do IR inspections? I know that Lynn DeGeorge in Houston is a knowledgable stucco inspector.

Originally Posted by Jim Luttrall

Maybe ignore the ICF requirements and focus on standard stucco requirements for drainage, flashing and WRB. It seems the ICF requirements are a red herring in this case since these folks are only concerned with the wall structure and likely will defer to the stucco or finish system requirements for water proofing.
If this was EIFS it is face sealed but traditional stucco still requires flashing and WRB no matter what it is applied over.

Jim,

Typically (all that I have seen - should I say the few all the I have seen) the stucco is applied directly to the ICF exterior foam form.

It is designed and intended to be that way. There is no need for a WRB ... okay, if the flashings are not done or done incorrectly, then a WRB might be needed to make up for it.

Think of an ICF house as a EIFS house except that the "exterior stud wall" is replaced with a solid poured concrete wall with steel reinforcing.

There is no place to install a WRB or a drainage plane. The only drainage plane is between the stucco and the foam of the ICF where the stucco comes loose.

The ICF's I have seen out here all have plastic inserts that create a web between the forms, the outside edge of these web reinforcements create a plastic "stud face" if you will, just under the surface of the foam block at 8" oc along the inside & outside faces of the forms. This allows furring strips on the inside for drywall, and on the outside lath can be screwed directly to the forms, allowing for reinforcement of the stucco that is applied without the WRB. Most builders do not apply a weep to the bottom of the wall, preferring to take the stucco below grade to cover the exposed ICF that may be above any waterproofing below grade. We always recommend that a weep be installed, but it rarely is. Taking the stucco down below grade eventually becomes an issue, however, out here it takes so many seasons for it to occur, most builders and original buyers are long gone by then. I have found that the problem occurs more quickly when there is a constant source of moisture applied to the immediate location, such as a planter, or a lawn that runs up to the stucco, and is much slower to emerge when desert landscaping with good drainage slope is applied directly against the stucco.
We don't see a lot of EIFS applied to this system simply because the type of foam used for ICF's is not acceptable for use with EIFS, and it cannot be sanded down because of the strips. Any EIFS applied over ICF should be immediately suspect.
The problem, of course, comes when this system is combined with conventional wood framing, creating many of the problems you are seeing.
JP is right, the details for the stucco system still need to be matched to the type of structure used, tho, with full ICF walls, those details would look more like those used in CMU block or CIP concrete construction, rather than wood framing.

Originally Posted by Rod Stewardson

The kicker is that the ICF website says that WRB's are not required which would mean to me that any amount of water on this wall would be acceptable. However, there has to be a wood framing/substrate connection where the ICF ends. This is my real concern. We all know the stucco is NOT water proof no matter how much elastomeric paint we put on it.

I don't think thats a good way to look at this.

any moisture will lead to a mould infection to the interior of the building.
and thats enough to get you in a mess with a buyer

Find out why and how the moisture in accessing the system and correct as necessary.

Best

Ron

Originally Posted by Ron Bibler

any moisture will lead to a mould infection to the interior of the building.

That mold is going to go through 6" - 8" of solid poured concrete?

You got some 'splaining do to ...

John,

I think that is the best explaination for the weep hole that I have. These are designed like a veneer wall to allow any moisture that penetrates the stucco to drain.

I wish I knew who the ICF Mfg. was so I could see their install instructions.

Thanks again for all the assistance.

Mold also needs food, there is none in an ICF wall.

Originally Posted by Jerry Peck

That mold is going to go through 6" - 8" of solid poured concrete?

You got some 'splaining do to ...

No. But the moisture can.

Best

Ron

Ron,

It will take a lot to drive moisture through that wall, first it has to get through the foam which is basically the same foam as ice chests are made from.

Does your ice chest leak?

Jerry you know the wall is put together in section. and there are air gaps and voids in every wall. ever look at a dam they leak. if you have a steady supply of water it may take some time. and if there is any way the water can wick its way to the interior it will. that is a fact.

may take some time but it can happen. You known what good Murphy says. "Anything that can go wrong, will go wrong."

Best

Ron

Originally Posted by Ron Bibler

Jerry you know the wall is put together in section. and there are air gaps and voids in every wall.

Ron,

Yes, I know they go together as building blocks, but the blocks are much tighter fitting that concrete blocks as they interlock - they are the forms for the concrete pour - it has to keep all the paste in and not let it flow out.

My point is that not much is going through there, not after being sealed up with concrete and not from their interlocking construction.

Yes ... EVERYTHING ... LEAKS ... but I doubt you will have a moisture problem inside through those walls (other than leaks around doors and windows).

And, yes, it you try to submerge an ICF structure in a large swimming pool, not only would it block your ability to swim around in the pool but it would leak - although an ICF structure setting high and dry ABOVE THE WATER LINE will react quite differently.

Originally Posted by Rod Stewardson

John,

I think that is the best explaination for the weep hole that I have. These are designed like a veneer wall to allow any moisture that penetrates the stucco to drain.

I wish I knew who the ICF Mfg. was so I could see their install instructions.

Thanks again for all the assistance.

rod,
google conform block or smartblock for all your specs!

The photos show several non related issues, there is not a "one stop fix" for this house.

As a long time ICF installer and stucco applicator, I would tell you that if you were advising someone on the purchase of this house that your best advice would be to let them know it needs serious help....

As mentioned earlier, the wood frame structure above the ICF PROBABLY does not have the proper drainage plane to shed water that has breached the stucco, furthermore, what about sweating on the inside surface of that wall?....I'm sure given the right weather conditions, there is plenty of moisture in the wall.

At the transition between the wood frame and ICF, I think a smarter move on the Builder's part would have been to set the wood framing out to the exterior such that the shelf with the rock is eliminated....Right now, that is just a catch basin for all water above to go into the ICF wall below....I doubt there is any type of flashing or membrane present, and if so, was it installed in a manner that it will work for this situation?...my bet is that it was not and this is why they drilled the weep holes below....to drain the water before it cuts across the cold joint at the slab/wall location (which probably alerted the owner or builder of the problem in the first place) .....check the baseboards on the interior, my bet is that wherever there are weeps drilled into the exterior stucco, there is some sign of damage inside.

The drilled weep holes are a big "NO NO" in terms of termite, fire ant and possibly carpenter ant infestation. This is just waiting to happen......same is true with the ICF foam going below grade with the stucco on it, there should be a termite barrier. If the ICF terminates at least 6" above grade, then this shouldn't be a worry, but the owner must make periodic inspections for termites as they should do with frame construction.

The roof to wall "sealant mess" obviously wasn't done by anyone that cared, or they were very ignorant of proper flashing details. There should be a reglet cut to the concrete wall such that a flashing could be sealed to the concrete which would eliminate any possible water passage from above to below. Regular step flashing would go up under that flashing.

Looks like the wood frame roof structure needs some attention as well as perhaps there is a water leak through the roof....in this case, the water is probably hitting the top plate of the ICF, going around it and down the wall between stucco finish and concrete.....normally, this water ends up running into the structure if it is a slab on grade structure...murphy says it will not drain out on it's own.

All too often, builders, owners and architects don't have much experience with ICF, so they make what they feel are sound decisions, but in this case, it appears that they are putting an awful lot of faith in the stucco to be able to totally shed water....There isn't one expansion/control joint visible in your photos, so common sense says it is going to crack...even hairline cracks suck up water and create havoc. In a few more years, that stucco will either start to chip along cracks due to expansion/contraction movement and start to possibly get some differential movement caused by the sun pulling moisture through the stucco. Putting Elastomeric paint on would be a big mistake, it will help for a year or so, but by the time it breaks down, the owners will have already had some intrusion issues, so they will want to repaint, but the problem then is that the substrate will have a moisture content unacceptable to the elastomeric, so from then on, the telltale sign of blistering and sagging paint will remain...

Perhaps you can investigate the drilled holes to see if they used a paper backed lathe?? If so, this is a big help, but won't help with water needing a place to go over openings...Does the rock shelf show any signs of being sealed? My bet is that closer investigation of the rock shelf will show hairline cracks along the mortar/rock connection that just begs for water to enter.

Take my thoughts for what they are worth, my opinions are based on the previous discussion and views of your photographs, this is nothing like being on the site and looking at the issues first hand.
Ian

Section 1704 will give you some information on WRB. If it is an eifs system on the concrete/foam then the eifs is the WRB. Drainage plane systems were not previously required on eifs prior to 2006. I do not have 2003 to confirm that code.


Looks like some of the homes in Hillcountry village

Steve Meyer