LVL stands for laminated veneer lumber: thin strips of wood glued under pressure and sized for whatever load capacity you need. They are typically used as beams, but I guess you can order up a thickness appropriate for bucks, which are not a big deal despite the pixels spent on them here. My advice is go with the flow. Reps are a good thing. You want a heart surgeon who does five bypasses a day, and you don't tell him what thread to use.

we regularly see air leakage through brand-new expanding spray foam. (The air seems to travel right through the “folds” in the foam—pockets of foam that don’t quite expand completely before they skin over.)

This would appear to be incorrect installation. It seems to go without saying that the foam vendors would not consider this kind of an application to be proper. They have guidelines on how large a void should be filled, I presume.

I also want to point out that every protocol I've ever seen uses foam "backer" rod as a backer to caulking and foam.

What's all this angst about something that is relatively simple?

Posted By ICFHybrid on 07 Nov 2013 07:36 PM

What's all this angst about something that is relatively simple?

It's unfortunately not done correctly most of the time and it's "complicated" to the wind installer who thinks that a bead of caulk will seal a window.

What's the point of building a tight home if the windows leak? Not to mention, the water intrusion and damage caused by the water intrusion.

It's a topic that receives a lot of attention on the building forums because it's a problematic detail that is not done correctly most of the time and it causes air and water intrusion.

Posted By Lbear on 07 Nov 2013 07:54 PM

Posted By ICFHybrid on 07 Nov 2013 07:36 PM

What's all this angst about something that is relatively simple?

It's unfortunately not done correctly most of the time and it's "complicated" to the wind installer who thinks that a bead of caulk will seal a window.

What's the point of building a tight home if the windows leak? Not to mention, the water intrusion and damage caused by the water intrusion.

It's a topic that receives a lot of attention on the building forums because it's a problematic detail that is not done correctly most of the time and it causes air and water intrusion.

There is one potential problem though, with making the window installation absolutely air tight. There is no such thing as "absolutely" air tight in building material. What can happen, as I see it, you can create a cavity around the window that is almost, but not quite, absolutely air tight. Subsequently, air will move in and out as the building exterior temperature fluctuates causing the cavity to become a vapor vacuum pump where cool night air is drawn in and bring in water vapor. But as that air warms up and some is expelled by expansion it will have a lesser relative humidity. Eventually the space reaches saturation point for vapor and vapor starts to condense out during cool hours.

How real this potential problem is in a particular climate I don't know, but water vapor being sucked into a closed space and condensing is real. In a building conference here several years ago one speaker said the reason we have so many old, 100+ years old, buildings still standing was because they were so leaky any moisture dried up before it could cause any rotting.

So, whatever method is used to close in a window, don't create a space that can't breathe in and out freely.

Posted By dmaceld on 07 Nov 2013 08:31 PM

In a building conference here several years ago one speaker said the reason we have so many old, 100+ years old, buildings still standing was because they were so leaky any moisture dried up before it could cause any rotting.

So, whatever method is used to close in a window, don't create a space that can't breathe in and out freely.

I agree, good points.

Most building science experts today would disagree that building structures "leaky" is the better method of building. Not to say that is what you are saying but the main reason WHY so many 100+ year old buildings are standing is because of many factors; one of which is the lumber was a better grade lumber than what we have today. It was denser, stronger, older, and contained less moisture. While these buildings might be "standing", they are far from comfortable, sound and energy efficient. I lived in one of those old homes and my utility bills were very high. The home had drafts and was uncomfortable to live in, especially in winter.

Many deep energy retrofits being done today on those older homes are revealing that they did rot and structural members have to be replaced during those remodels.

That is true that if water enters a space within the window flashing area, it should be able to dry. That was addressed in the article. The main goal is always to prevent the water from getting in that space. One place water should never be entering is within the wall cavity of a home. If it does, something was seriously done wrong during construction. If water makes its way past the exterior cladding (stucco, siding, etc) and then makes its way past the house wrap and onto the OSB sheating, there are other serious problems going on.

There are more problems with window details being done incorrectly and the subsequent interior leaks and water damage then there is with window details being done correctly and creating a tight and leak proof detail.

What is undeniable is that sealing the windows with caulk and calling it a day is not sound practice and is guaranteed to cause issues later on.

Another good point is that whatever method your builder uses is most likely going to be the method you are stuck with. Most builders don't like change and introducing a new methodology is something they don't care for.

• Spray foaming around the window and calling it a day will guarantee the window will leak air and moisture in those areas
• Details matters and using a sealing method that remains flexible is the better solution - foam tape seems to be the answer the pros agree on
• The belt & suspenders approach works best - layer the sealing methods
• The sill must slope away from the window - don't create a slope towards the window (I've seen this done on pop-outs)
• The less dissimilar materials in that area, the better - if you have 2 or 3 materials all expanding and contracting at different rates, that is bad for sealing
• Untreated wood works better than treated wood - the treated wood has a lot of moisture in it and will split and twist more than untreated wood

Posted By Lbear on 07 Nov 2013 06:51 PM
Getting back to the spray foam around the windows, this is from an article in Fine Home Building:

"If you’re lucky and have a builder who is careful and up to date, the window will be sealed at the perimeter with expanding spray foam, which works OK as an interior air-and-water seal. During blower-door tests, though, we regularly see air leakage through brand-new expanding spray foam. (The air seems to travel right through the “folds” in the foam—pockets of foam that don’t quite expand completely before they skin These leaks occur even before the lumber dries and shrinks away from the cured spray foam. We’re convinced that water travels right through most spray foam installations around windows, especially under the pressurized conditions of a Maine nor’easter." (emphasis mine)


The air and water leakage occurs BEFORE the lumber dries and shrinks away from the cured foam. Even flexible cured foam is not flexible enough to bridge the gap when the wood pulls away from the spray foam. So if spray foam is leaky from day one (as verified by numerous blower door tests and building science experts), how leaky does spray foam get over the course of 5+ years after the wood dries and pulls away?


FINE HOME BUILDING

I can see the water through the foam if someone is trying to squeeze the last few drops out of a can as it doesn't have the pressure to properly expand however we are talking ICF which means we have around 11" of foam fill. If you shoot the back half full and then let it expand and come back and fill the final quarter, I don't think you will have an issue. Just because FHB says it's an issue doesn't mean it is. I think we need to see some details of the issues they are finding before we just accept that as gospel. If the foam will secure the window in place (and it does) I'm not buying into this leakage just yet.

As pointed out in an earlier thread, EnerBond foam is designed to act even as a subfloor adhesive.

With regard to FHB's In-Betweenies, I really don't see any advantage in doing this. Most modern windows already have drips and caps attached as nailing flanges. Why repeat that on the outside? They are just making thing more complicated then needs be. Just teach people to do it right the first time. Don't give them more chances to mess up by making it more complicated. There may be some advantage to innies as far as reduced wind scrub of the glazing but the complications of installing either In-Betweenies or innies out weighs this advantage as far as I can see. Keeping the nail fins (assuming they are one piece and integral to the window frame) in plane with the outside air barrier makes more sense to me.

Posted By FBBP on 07 Nov 2013 10:52 PM
Just because FHB says it's an issue doesn't mean it is. I think we need to see some details of the issues they are finding before we just accept that as gospel. If the foam will secure the window in place (and it does) I'm not buying into this leakage just yet.


With regard to FHB's In-Betweenies, I really don't see any advantage in doing this. Most modern windows already have drips and caps attached as nailing flanges. Why repeat that on the outside? They are just making thing more complicated then needs be. Just teach people to do it right the first time. Don't give them more chances to mess up by making it more complicated. There may be some advantage to innies as far as reduced wind scrub of the glazing but the complications of installing either In-Betweenies or innies out weighs this advantage as far as I can see. Keeping the nail fins (assuming they are one piece and integral to the window frame) in plane with the outside air barrier makes more sense to me.

It's not only FHB that is making this claim, many building science experts have done blower door testing and the spray foam in a can around the windows is proving to be a weak point in sealing. Green Building Advisor has done some studies and articles into this issue and it comes down to the simple fact that spray foam doesn't seal 100% and the bigger factor is that the window will move, as will the wood around it, breaking the seal of the spray foam. Utilizing a method that uses a flexible seal that will expand and contract with the movement of the windows, works best.

The "in-betweenies" or "innies" advantage also comes into play in that it provides better energy #'s than the same window that is flush mounted. They have studies showing a 20% energy benefit from installing within the window buck area instead of flush mounting.

European triple pane windows don't have nailing fins, they can be flush mounted with the clips but they are typically mounted in the center of the window cavity.

FROM GBA:

Chris Makepeace, a certified engineering technologist at Alberta Infrastructure in Edmonton, Alberta, favors innie windows. “The window should be totally supported by the structure of the wall,” Makepeace told EDU. “If the window is toward the inside, then the bulk of the window frame is able to ‘see’ the interior heat, and the window is at a more constant temperature year round. If we extend the window farther to the exterior, we increase the water leakage potential.”

Jack Hebert, president of the Cold Climate Research Center in Fairbanks, Alaska, also prefers innie windows. “It creates a pocket where you don’t get as much wind across the face of the window,” Hebert told EDU.

Thorsten Chlupp, a builder in Fairbanks, Alaska, agrees with Hebert that innie windows are best. In an article published in the Journal of Light Construction, Chlupp explained his preference for innies: “Windows can be installed either at the face of the sheathing — in a recess — or out at the face of the wall. From a performance standpoint, a recess is better, because the window is somewhat protected from wind-washing and the interior glass is more easily warmed by the heat in the room. By contrast, windows installed at the face of the wall are in an interior recess, separating them from the warm air inside (especially if a curtain is drawn) and exposing the outer layer of glass to cold wind. I’ve observed that in extremely cold weather — when it’s 25°F below zero, for example — frost tends to form inside windows installed at the face of the wall, whereas frost rarely occurs on inset windows. I’ve installed windows both ways, but because of the frost problem I now do only recessed installation.

Bear - could you point us to some of the studies showing 20% benefits?

I agree that the reduction of wind wash is a factor but to say it reduce water leakage potential is a non starter for me. If it's not simple, someone will mess it up. To simply tape the barrier to the nailing fin is as simple as it gets.

While there is definite advantages to not having ice forming on a window, it does not mean an increase in energy efficiency. The fact that the ice is forming means there is less heat loss in the deep recess. Also if the window is kept warmer by mounting it to the inside, that means there is more heat loss and bypass by the extended jamb to the inner wall core.

One other point with innies, it is a substantial view changer.

Posted By FBBP on 07 Nov 2013 10:52 PM

Posted By Lbear on 07 Nov 2013 06:51 PM
Getting back to the spray foam around the windows, this is from an article in Fine Home Building:

"If you’re lucky and have a builder who is careful and up to date, the window will be sealed at the perimeter with expanding spray foam, which works OK as an interior air-and-water seal. During blower-door tests, though, we regularly see air leakage through brand-new expanding spray foam. (The air seems to travel right through the “folds” in the foam—pockets of foam that don’t quite expand completely before they skin These leaks occur even before the lumber dries and shrinks away from the cured spray foam. We’re convinced that water travels right through most spray foam installations around windows, especially under the pressurized conditions of a Maine nor’easter." (emphasis mine)


The air and water leakage occurs BEFORE the lumber dries and shrinks away from the cured foam. Even flexible cured foam is not flexible enough to bridge the gap when the wood pulls away from the spray foam. So if spray foam is leaky from day one (as verified by numerous blower door tests and building science experts), how leaky does spray foam get over the course of 5+ years after the wood dries and pulls away?


FINE HOME BUILDING

I can see the water through the foam if someone is trying to squeeze the last few drops out of a can as it doesn't have the pressure to properly expand however we are talking ICF which means we have around 11" of foam fill. If you shoot the back half full and then let it expand and come back and fill the final quarter, I don't think you will have an issue. Just because FHB says it's an issue doesn't mean it is. I think we need to see some details of the issues they are finding before we just accept that as gospel. If the foam will secure the window in place (and it does) I'm not buying into this leakage just yet.

As pointed out in an earlier thread, EnerBond foam is designed to act even as a subfloor adhesive.

With regard to FHB's In-Betweenies, I really don't see any advantage in doing this. Most modern windows already have drips and caps attached as nailing flanges. Why repeat that on the outside? They are just making thing more complicated then needs be. Just teach people to do it right the first time. Don't give them more chances to mess up by making it more complicated. There may be some advantage to innies as far as reduced wind scrub of the glazing but the complications of installing either In-Betweenies or innies out weighs this advantage as far as I can see. Keeping the nail fins (assuming they are one piece and integral to the window frame) in plane with the outside air barrier makes more sense to me.

We are going with innies from a functional and cosmetic standpoint, not from any kind of performance.  Because we are using in swing windows, we would like the ability to open them a full 180 degrees so that the window is totally out of the way, and if we have them as outies, then we could only open them about 90 degrees.  From a cosmetic standpoint, we think that having some depth to the window will look nicer, but that is subjective.

With our windows lack of flanges, it won't make any difference to the installer where he is placing the window.  At least, he told me he didn't care where we placed the window.

Posted By dmaceld on 07 Nov 2013 08:31 PM

Posted By Lbear on 07 Nov 2013 07:54 PM

Posted By ICFHybrid on 07 Nov 2013 07:36 PM

What's all this angst about something that is relatively simple?

It's unfortunately not done correctly most of the time and it's "complicated" to the wind installer who thinks that a bead of caulk will seal a window.

What's the point of building a tight home if the windows leak? Not to mention, the water intrusion and damage caused by the water intrusion.

It's a topic that receives a lot of attention on the building forums because it's a problematic detail that is not done correctly most of the time and it causes air and water intrusion.

There is one potential problem though, with making the window installation absolutely air tight. There is no such thing as "absolutely" air tight in building material. What can happen, as I see it, you can create a cavity around the window that is almost, but not quite, absolutely air tight. Subsequently, air will move in and out as the building exterior temperature fluctuates causing the cavity to become a vapor vacuum pump where cool night air is drawn in and bring in water vapor. But as that air warms up and some is expelled by expansion it will have a lesser relative humidity. Eventually the space reaches saturation point for vapor and vapor starts to condense out during cool hours.

How real this potential problem is in a particular climate I don't know, but water vapor being sucked into a closed space and condensing is real. In a building conference here several years ago one speaker said the reason we have so many old, 100+ years old, buildings still standing was because they were so leaky any moisture dried up before it could cause any rotting.

So, whatever method is used to close in a window, don't create a space that can't breathe in and out freely.

We are planning to use Siga tape, and the sales representative says that it is similar to gore-tex in that water vapor can pass through it.  I hope that the claim is not false.

eugenepan
If I was using in swing windows I would also consider innies. Definitely the strongest argument for them.

As far as cosmetics, for sure in the eye of the beholder. For me I like my window sills ;-)

Posted By FBBP on 08 Nov 2013 01:07 AM
eugenepan
If I was using in swing windows I would also consider innies. Definitely the strongest argument for them.

As far as cosmetics, for sure in the eye of the beholder. For me I like my window sills ;-)

The problem I am worried about is people placing stuff on the window sills, and then someone opening the window and knocking it off.  I have small kids, so I know they would put stuff there, and I wouldn't be paying attention, and then whatever juice or milk would be all over the floor.

eugenepan, my windows are tilt-turn inswing German construction with no flange. I didn't have an ICF install, but still I would think they would be ideal for that specifically because of the lack of a flange. So in Europe normally they are installed in masonry or aerated concrete with an expanding bolt going through the frame in a plane parallel to the window glass. The bolt is sort of like a wedge anchor. Are the mounting holes in your windows not oriented that way?

Posted By Jelly on 18 Nov 2013 02:06 PM
eugenepan, my windows are tilt-turn inswing German construction with no flange. I didn't have an ICF install, but still I would think they would be ideal for that specifically because of the lack of a flange. So in Europe normally they are installed in masonry or aerated concrete with an expanding bolt going through the frame in a plane parallel to the window glass. The bolt is sort of like a wedge anchor. Are the mounting holes in your windows not oriented that way?

My mounting holes are just like you mentioned.

The main issue was that with innies meaning flush to the inside or greater, the window would actually have very little or no concrete contact.  It could only connect to foam, and foam isn't strong enough to hold up some of these heavy windows.  We plan to use lvl bucks, and then we will use another layer of lvl as the window mounting surface.  now, we won't have to worry about where we connect from the window frame to the house. 

We want to actually overhang the foam by the finish thickness, so that is another 5/8", so that is >3" of window frame not touching any concrete.

Gotcha, I understand now. I didn't realize that the foam of the ICF blocks was that thick.

Posted By Jelly on 20 Nov 2013 05:37 PM
Gotcha, I understand now. I didn't realize that the foam of the ICF blocks was that thick.

I am using Amvic's standard product, and the foam is about 2.5". They have a new product that is 3.25", but I didn't know about it at the time, and it is probably overkill for my area.  Some of my friends don't even insulate their homes and still have single pane windows. Not by choice, but it was the home they bought, and some of the Eichler homes are hard to really modify without basically replacing the entire home.  At least, that is my impression.  It is mostly windows, so if you change all of the windows, you might as well change the whole house.

Oh! You're in California, yeah you could probably get away without insulation in some areas there. But I guess ICF is good seismic protection, and fire resistant too.

Posted By Jelly on 22 Nov 2013 06:18 PM
Oh! You're in California, yeah you could probably get away without insulation in some areas there. But I guess ICF is good seismic protection, and fire resistant too.

I am going with ICF for a couple of reasons.  One, it will much quieter.  Two, the temperature will be more stable.  Three, the house would seem stronger.  Four, my energy cost would be lower.  I don't think the cost is actually that much higher because labor is so expensive in California, and then there is so many extra things that must be done to a wood home to meet the new code, especially seismic.  My friend's home is being built, and he has quite a bit of steel in it with the bolts to the foundation, the hardy frames, the straps.  I was quoted $90k by a big builder just for labor to frame my interior walls and to install the trusses.  Of course, that is probably on the extreme side.  I got about 10 quotes, and many of them quoted a high number just for the interior walls, so I am assuming a similar or higher number for the exterior walls.

Eugenepan - what solution did you choose in the end?
I would be most interested to find out what buck and flashing details you used.