We are looking for advice/suggestions on the best window flashing method and materials on a ICF home. Below is the project information. We have talked to several installers and all have different ideas. Below are two of the options propsed by different installers. Installer one is what our builder proposes. This installer however is not certified or insured. Installer 2 is Tyvek certified and has insurance.

FoxBlock ICF
2x12 Pressure Treated Window Bucks
Jeld Wen Siteline EX Wood Glad Windows with Naling flange
Exterior Finish Brick Venner with 1 inch air gap
Building is Located in South Texas. Hot and very humid.
Suresill Pans and HeadFlash
33 Windows

Installer 1 -
Suggests the Following:
Seal entire buck with Aqua Flash
Install Sure Sill Window pan and seal corners with Aqua Flash
Put in Window and Nail
Seal Sides and top with Aqua Flash
Install Sure Sill Head Pan and Aqua Flash Top

One concern with Aqua Flash is it is designed ot be covered with Stucco. Not sure if humid air will have any effect on it or break it down. Another concerned is that Aqua Flash can develop holes and if not installed by skiller labor can leak.

Installer 2
Seal bottom of buck with Tyvek Liquid Flash
Install Sure Sill Window pan and seal tape corners using
StraightFlash or FlexTape
Put in Window and Nail
Seal Sides and top with StraightFlash tape
Install Sure Sill Head Pan and seal with StraightFlash tape

Posted By jwerkmeister on 27 Jun 2015 01:36 PM

My advice is NOT to use an installer who is not licensed, insured and bonded. The might do an OK job but if they don't, you have no recourse.

Questions:

1 - Who decided on the Jeld  Wen windows? They are not that great of a window, better options exist. Online it shows the U-Values from 0.31 - 0.46 depending on the options you choose. Was it the builder who chose Jeld Wen?

2 - Why are they using Tyvek on an ICF wall?

3 - Are they nailing the window flange to the wood window buck or are they assuming they can nail into the ICF webs?

4 - Do you have architectural details for the window installs?

5 - Do any of the installers have experience in install windows in an ICF wall and flashing those windows with a stucco finish?


I believe they are applying and using wood wall install methods on an ICF wall.

We decided on the windows. We wanted a wood clad window. Our options have U values of around .33 which is fine for our needs. They are not using Tyvek wrap. The builder wants to use the installer with the liquid applied Aqua Flash. The 2nd installer wants to use the Dupont Flashing tapes like StraightFlash or Flexwrap. The window flanges will be nailed into the bucks. Both installers have ICF experience. Exterior finish is brick veneer and not stucco.

The builder wants to use the installer which is not insured or bonded. I want to switch to the 2nd installer which is insured and also has a lot more ICF experience as he is a ICF installer and ICF builder. He is the installer our builder hired for the ICF install.

Posted By jwerkmeister on 28 Jun 2015 12:05 AM

The builder wants to use the installer which is not insured or bonded. I want to switch to the 2nd installer which is insured and also has a lot more ICF experience as he is a ICF installer and ICF builder. He is the installer our builder hired for the ICF install.

The builder wants to use the non-insured or bonded installer because he is probably the least expensive and therefore the builder has less overhead on the install. Which means more $$ in his/her pocket.

I would go with the 2nd installer.

I know this was like a year ago, but do you have any pictures of the flash detailing on your build? I will be soon in this same predicament and I'm trying to determine the exact materials I will need and the install details.

berky

What kind of buck are you using? Wood, foam or ...?
Are you installing innies or outies?

Fox buck (foam) and window (zola) placed in center (recessed in both directions).

Doors will be the same way

I'm planning to use the more or less the same setup. I am also planning for stucco siding. I could not find any acceptable flashing details for stucco using foam bucks from any of the ICF manufacturers. I'm thinking to have a metal casing all around the window opening - ideally aluminum. The casing will also serve as flashing at the top and bottom and for this reason will have to extend over the top of the window frame and also under at the bottom and lightly sloped. One idea is to actually install the top and bottom bucks slightly sloped so the bottom and top sills will be easily held in place.

mine will be vinyl siding, but 2 of the windows will have stone veneer on the bottom portion of it.

so, I was thinking using a liquid-applied membrane on the foam buck and around the edges (not the whole way on the inside though).

then, using aluminum flashing over that, angled on the bottom sill (flat on sides and top). my biggest issue I have trouble visualizing is how the flashing connects to the window frame. do you use a caulk of some sort? It seems there has to be a sealing of some sort since (at least on the bottom), the flashing would be in front of the window, which is bad for water drainage.

but what do you put under the metal flashing to keep it angled? shims? how do you secure it down so wind doesn't rip it off?

for me, I understand the basics of what needs done, it's just those minute details that make all the difference between a good install and bad that I'm still not fully grasping. I need a video (or tons of pics) of someone doing my exact install....

I'm about 1.5 to 2 months away from windows being installed.

Does anyone know any good videos or better info on how the flashing (the aluminum I mean -- I'm good on the air/water barrier -- Siga tape) is installed in this case? I'm still doing my own research as well and if/when I find something good, I'll post it here.

berky
did you pour the walls already?

basement walls will be poured on wednesday. they did pour the base wall for the garage and the frost footer wall for the back side of the basement (about 24 inches or so just so the full pour wasn't quite as high -- it's a walk-out basement)

Here is what I was planning to do: Order a custom flashing that will be inserted over the buck's lip and follow the buck's shape to the exterior The flashing should extend out of the ICF enough to meet the code requirements and should have drip lip. I created a drawing in 3D showing how this would work. The idea is to make sure the flashing is inserted into the concrete and is angled up a bit. In my drawing it shows the lip of the buck (it was made for a Logix buck which has a taller insert lip than the Fox buck). If you use Fox buck there is nothing to cut from the buck's lip really since it's already low. Maybe spray some foam under the angled flashing so the weight of the concrete doesn't push it down flat against the buck. If it gets pushed flat against the buck it kind of defeats the purpose as you want any water dripping from the outside of the concrete to not be able to travel to the inside. On my side I have decided to use metal siding and that will significantly alleviate my flashing requirements, rain screen, etc.

It looks like the attachment didn't work.
Here is the link https://drive.google.com/file/d/0B6cwnkZ3GHaaOGwxVG1fMnhEbkk/view?usp=sharing

Interesting. is it a requirement to have the metal flashing the whole way into the concrete? is that a big problem? I ask because I had planned to cut an upward angle into the foam to insert metal flashing after-the-fact.

I had planned to do something *basically* like the attached:

I was told by the window manufacturer (Zola) that since I have vinyl windows, the interior air barrier tape isn't really necessary.

The Weather Barrier and Air Barrier would both be the Siga Wigluv, just different widths. Thanks for the responses. Seems like there's a 1000 ways to do it, just have to find something that works right for the specific situation. I'm also not sure how the bottom sill flashing would look going over top the stone veneer for 2 of the front windows. I'll have to figure that one out too.

Me thinks that the flashing needs to go in the concrete so any water sipping from above down the concrete wall will make it's way out for sure.

If you insert it after the fact you can't possibly make sure it's 100 % sealed against the concrete. Just think about it : you will need to cut through foam, the concrete is never straight inside but there will be some bits of foam stuck in the concrete anyway so I don't think you can get a completely flat strip of concrete to glue your flashing against.

Going with the flashing in the an extra 1/2" should not be a problem - you buck has a very shallow lip anyway. Gorilla and Logix have a 1.5 -2" lip compared to Fox buck. Just make sure you use aluminum flashing or at least galvanized steel so it won't rust over time.

but if water is getting into the concrete, wouldn't it diffuse through the eps to the outside? it's not like there'd be a gap between the eps and concrete for it to 'run', right?. I'm sure your way will be better anyway, but at the same time, if there's water in the concrete, it can go right around the metal through the same process.

have you had problems with flashing it another way? or is this your first build as well?

so aside from that particular portion of flashing, what are you going to use against the exposed EPS? I just watched a video today where they used the Apex (?) white plastic 'boards' to create the header, jambs, and sill (https://www.youtube.com/watch?v=5jL8Iwy4FBE). granted, that was a wood-based framing install, but it was almost exactly the scenario I'll have. The one thing I don't have that was in the video was the attachments that they fit the extension into, which, of course, is where I'm having the most trouble visualizing. The best I've come up with is what I posted above. I could stick the pan up under the front of the window (only like a half inch or so in), but then I'd have to figure out how to apply the Wigluv. It would be really nice if the sash on the window had an 'overhang' where the tape and metal flashing could go up under.

Are you going to cut the foam at all to create a slope on the sill? what about the top?

First of all you don't want water to get into the EPS at all. If it does it compromises the R value of the EPS.
But if somehow it does get there it won't pass through the concrete but it will leak down the wall. Where it reaches the foam buck it may start finding other ways and get above the window frame. This is what you want to avoid as water inside the house is much worse than lost R value on the outside.
Unless water will be trapped there and start ponding on the flashing I drew I don't see how it will go up around the metal and the concrete.

right, but with eps being open-cell, it should dry out 'relatively' quick depending on the season. concrete will absorb water as well (like a slab on ground weeping it up - which is what I was referencing), I guess that is unless you use something like xypex or similar in the mix. I'd have to assume that if water gets between the EPS and concrete, it's path downward would be extremely slow, such that it should be able to dry outward through the foam before it could make its way down. of course, that's just my assumption, and I'm not trying to turn this into an argument.

Anyway, I'm more interested in the 'pan' flashing / exterior jamb extensions. What are your plans for that?

Beyond the window head flashing I haven't thought too much about the rest of the assembly.

Since I decided to go with metal siding I'm less worried about water getting in as along as the flashing has the drip outside the siding.

For the sill I think the easiest thing to do is to slope the buck down towards the outside. That could be done in two ways I'm thinking.
Either install the whole bottom buck at an angle (like 1/4:12 so for a ~12" ICF wall) by cutting off the EPS about 1/4" from the outer ICF under the bottom buck.
Or install the bottom buck normally (100 % horizontal) and shave off the top of the foam on the top side of the buck that is outside and starting from the inner edge of the window frame. The Fox buck being only foam on the outside that should not be a problem. With Logix or Gorilla buck that will require shaving off the plastic strip on the edge of the buck as well.

Whatever finishing and water proofing surface you put on top of the buck will have to follow the slope that you created.

In that way any water arriving on the sill will drip down on the slope of the sill. For the sill surface just make sure to have a drip edge extending outside the siding.

BTW, this will be my first build as well.