Thread: window flashing

Does this window look properly flashed?

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Originally Posted by Ron Bishop

Does this window look properly flashed?

Do you mean the lack of tape/flashing material on the fins? The lack of siding covering the fins?

the lack of tape flashing on the fins.

Joking right.

Here is a site that helps.Window Flashing, Window Leaks and Window Leak Repair,How-to Pictures

I don't know why the guy in the link is using all that metal if the window has a nailing flange. Simplified window installation: Put Tyvek (or similar) on, make diagonal cut to the corners of the rough opening, staple to inside of RO. Tape around RO. Install window, nail flange as directed, tape over bottom of flange, tape sides, then tape top. Install drip cap then siding.

Some windows come in pairs or sets, and only need taping around perimeter of set. Can't really tell if yours is one, but I think not. Confused by the little "flap" on the left side of the siding piece in the middle that has no twin on the other side.

I doubt that the fin is nailed properly (might be, but I doubt it).

Oh, silly Kristi, I didn't even notice before they were two different types of windows, one fixed, one casement.

Definitely not taped well enough, probably not nailed well either, as Jerry pointed out. Is that a puncture just to the left of the strip of tape? Those little center bits of siding should probably be glued on. Huh.

This is a test, right? Answer is NO!

Originally Posted by Kristi Silber

Definitely not taped well enough, probably not nailed well either, as Jerry pointed out. Is that a puncture just to the left of the strip of tape?

Kristi,

That is a fastener hole, which is why I stated "I doubt that the fin is nailed properly (might be, but I doubt it).", and "might be" is the key as some I see requires anchor spacing in each hole and some in every other hole (not stated that way, but stated as every 12" and the holes are on 6" centers, while some may say every 6" with the holes on 6" centers, and some are every hole with nails and every other hole with screws).

Without the engineering we just do not know what is required, the only thing we do know is that there is no fastener in that one fastener hole.

The link provided by Bob Elliott depicts an excellent flashing method. However, it far exceeds any requirement that a production builder can be held to. Be careful about using it as a standard for inspection.

Originally Posted by Darrel Hood

The link provided by Bob Elliott depicts an excellent flashing method. However, it far exceeds any requirement that a production builder can be held to. Be careful about using it as a standard for inspection.

No one can hold a builder to any standard other than a code inspector, and they can only hold the builder to the minimum standard .. the code.

Depending on the contract, the buyer may be able to hold the builder to a higher standard.

Keep in mind that there are production quality high-end home builders and there are production minimum code low-end home builders.

Jerry,
I agree 100% with your characterizations of builder categories. That is why I said "be careful."

I frankly can't follow exactly all the guy in the link is doing to flash the window, especially since it's a mock-up and I don't know what the photos are missing. His lack of tape over the top flange is to my eyes a mistake, and the flashing in general unnecessarily complicated. There apparently is no j-channel around the window. "Real window flashing is made of metal." That's just not true these days. And if you are going to flash the windows with metal it should really be in just two pieces, one at the bottom and one around the top and sides. The more seams there are, the more potential for water to be wicked under them if it does make it through the siding.

The "flashing" of windows with attached flanges can usually be safely done with bituminous tape alone (after nailing the flange according to factory specs). These were sided with HardiePlank, but would work with vinyl or cedar too.

Kristi around here they overlap the barrier over the tape along the top of the window. Best practice for any exterior facade is in a shingle manner. Upper always overlapping the lower.

In the photos you can't tell, but the barrier is over the flange at the top, then taped. Forgot to add that detail, but it's a good point. There's more detail to the way I've done taping that I didn't go into, like how to deal with the corners and preserve the upper overlapping lower aspect.

It the barrier just loose then, if over the tape at the top? How is it attached?

All seams and overlaps on moisture barriers should be taped. They tape them here.

That's almost exactly how I've done it, the main difference being the bottom of the flange was taped on the outside, too. Didn't usually need diagonal bits at the top unless the house wrap was cut too far. (Usually the house wrap wasn't as wrinkled at the top tape as that in the photo...not a good example!)

Originally Posted by Kristi Silber

I frankly can't follow exactly all the guy in the link is doing to flash the window, especially since it's a mock-up and I don't know what the photos are missing. His lack of tape over the top flange is to my eyes a mistake, and the flashing in general unnecessarily complicated. There apparently is no j-channel around the window. "Real window flashing is made of metal." That's just not true these days. And if you are going to flash the windows with metal it should really be in just two pieces, one at the bottom and one around the top and sides. The more seams there are, the more potential for water to be wicked under them if it does make it through the siding.

The "flashing" of windows with attached flanges can usually be safely done with bituminous tape alone (after nailing the flange according to factory specs). These were sided with HardiePlank, but would work with vinyl or cedar too.

The problem with that method is that when, not if, the window leaks, the water just goes into the wall. Much better to have a pan type flashing below the window to controll ALL the leakage.

Originally Posted by Mark Cramer

Much better to have a pan type flashing below the window to controll ALL the leakage.

While a pan type flashing can help with some types of windows, pan type flashings are not cure-alls for all styles of windows.

Pan type flashings under windows also do not control ALL the leakage where pan type flashing may work for most of the leakage.

Then, of course, there is flashing the pan flashing in so that the leakage it can control does not go outside the pan where the pan cannot offer any help at all.

Windows have different ways of dealing with water; in the end, best to go with manufacturer's installation directions.

A well-sided, -flashed and -trimmed house should not have water behind the siding in the first place!

A well-sided, -flashed and -trimmed house should not have water behind the siding in the first place

That's is not true for all siding. Vinyl siding is a rain deflector and cannot keep water out at termination points and protrusions. This is why they state to have a barrier and they provide weep holes in the bottom edge of all panels.

Brick veneer, stone, and a few others is another example.......

Originally Posted by Kristi Silber

I don't know why the guy in the link is using all that metal if the window has a nailing flange. Simplified window installation: Put Tyvek (or similar) on, make diagonal cut to the corners of the rough opening, staple to inside of RO. Tape around RO. Install window, nail flange as directed, tape over bottom of flange, tape sides, then tape top. Install drip cap then siding.

Some windows come in pairs or sets, and only need taping around perimeter of set. Can't really tell if yours is one, but I think not. Confused by the little "flap" on the left side of the siding piece in the middle that has no twin on the other side.

Your installation methods are 100% incorrect. That was proven years ago to be one of the major flaws in window installation, and why windows and there installations are failing. All the metal he is talking about is called pan flashing. A fail safe way of determining how a window should be installed can be determined by looking at the window manufacturers installation guidelines. If you are not sure who the manufacturer is then use one from a major brand because they are all very close.

Joe Lstiburek has an excellent reference book on water management.

Originally Posted by Paul Phillips

Your installation methods are 100% incorrect. That was proven years ago to be one of the major flaws in window installation, and why windows and there installations are failing. All the metal he is talking about is called pan flashing. A fail safe way of determining how a window should be installed can be determined by looking at the window manufacturers installation guidelines. If you are not sure who the manufacturer is then use one from a major brand because they are all very close.

The is what I said just a few posts ago:

"Windows have different ways of dealing with water; in the end, best to go with manufacturer's installation directions."

We were following installation guidelines. Maybe they've changed, I don't know.

I always thought that things like house wrap and drainage holes were back-up systems, like tar paper on roofs is. I would think that if water behind siding was that common there would be a lot of mold growth, a lot more deterioration of trim, etc. If builders are relying on house wrap to keep the walls dry, I don't see why sealing the whole perimeter of the window with bituminous tape is any different, as long as that's how the window is designed to be installed.

It's true that earlier, in the post Paul quoted, I was hasty, careless in my writing, and speaking too generally.

Open-jointed rainscreen systems - now they're designed to get wet behind the siding.

Originally Posted by Paul Phillips

Your installation methods are 100% incorrect. That was proven years ago to be one of the major flaws in window installation, and why windows and there installations are failing. All the metal he is talking about is called pan flashing. A fail safe way of determining how a window should be installed can be determined by looking at the window manufacturers installation guidelines. If you are not sure who the manufacturer is then use one from a major brand because they are all very close.

I couldn't agree more! Upper must overlap lower, refer to WRB and window mfg install instructions!

Kristi
A rainscreen detailed siding application is not necessarily designed to get wet but to allow any incidental moisture the ability to drain and not overwhelm the WRB and migrate to the interstitial cavity. While it is true that the siding is the first line of deflection of exterior moisture it is not 100% effective. The WRB (weather resistant barrier) and its detail of installation is the final line of defense against moisture intrusion into the building envelope. We can see that with all of the EIF system failures.



The original EIFS was installed in a barrier style application where it was the primary deflection of any exterior moisture and it had no backup plan if moisture got behind its sealed face. That is why the system had to be installed perfectly and maintained perfectly. It generally failed a little higher in the wall and would fill up with incidental moisture that could not escape at the lower edges. This moisture would sit and overwhelm any building paper if there were any. Early on this was figured out but the sloppy details were allowed to go on for years and I still see some of our good protective details being ignored to this day.



The sill pan type installation is great work well with windows that are being installed in an assembly that allows good drainage. Water managed EIFS, vinyl or steel siding, or any assembly that incorporates rain screen principals. The problems I am seeing is with windows that do have the pan flashing details but are dammed up with a window trim board that is caulked and sealed so nicely that the pan can’t drain, seems no one thought of that.


The pictures are of trim that is rotting due to the window leak not being able to get back out efficiently so it perks through the trim board from behind and degrades from the rear.



The first two have the trim that is degrading from the back side due to improper detailing that will not allow moisture to drain and the next three show a window that was removed after all of the AMV (faux stone) was taken off. This is a 1M$ home with 250K worth of moisture related damage because the cladding was not drainable, water will get in behind the cladding. the home is 10 years old

Great detailed info Mark.

I thought that an open-jointed rainscreen system is designed with the idea that it will get wet behind the cladding - it's not meant to entirely hold water out. Other systems (masonry veneers, vinyl, EIFS, etc.) are designed to deal with moisture if it gets in, but generally people don't intentionally install them with open gaps which allow it to happen, do they?

Seems to me a window leak will cause problems over time even if it does get drained well.

I admit I was wrong in saying most windows can be flashed using just bituminous tape. I don't know about "most" windows. As I've said 3X now, follow manufacturer directions. And naturally, upper must overlap lower.

The problems I am seeing is with windows that do have the pan flashing details but are dammed up with a window trim board that is caulked and sealed so nicely that the pan can’t drain, seems no one thought of that.

Shouldn't it then drain behind the siding? I thought that's how pan flashing worked. It has to drain outside?

And doesn't pan flashing mean there's less insulation under the window?

Kristi
In order for the pan to drain provision has to be made for it to drain.
You can put the WRB assembly together including properly installed windows then apply the cladding and dam up critical drain areas.

The pan assembly done correctly will change the position of the insulation at the bottom of the window. the insulation line will be more to the interior of the window at the bottom instead of at the nail fin at the sides and top. This insulation needs to be low expanding closed cell foam that is designed for windows and doors. It still needs to be installed with some care as it too can push on the jambs although nowhere close to the foam of a few years ago.

The rainscreen system that enjoys a high degree of success is the ventilated or pressure equalized rainscreen. I think open jointed rainscreen is a poor description of what we are trying to achieve in the building industry. it brings to mind sloppiness and poor details.
You are correct that a window leak is a problem and brings with it much damage over time. A properly detailed and drained sill pan will keep that moisture form storing up in the assembly and creating the devastation that is shown in my pictures. most of this moisture is incidental in nature and if drained does do much damage but you can see what it does when it is trapped and stored. Stored moisture will overwhelm the WRB and go right through given enough time.

am also currently reviewing a five year old brick home where all of the windows are leaking because no through wall flashing was installed to protect the lintels.

All of the brick will be removed and started over this summer, 260K

The rainscreen system that enjoys a high degree of success is the ventilated or pressure equalized rainscreen. I think open jointed rainscreen is a poor description of what we are trying to achieve in the building industry. it brings to mind sloppiness and poor details.

I've been googling and reading about rainscreen systems. So do you think the drained/back ventilated ones don't work? I think open jointed rainscreen is an appropriate name - it describes it well visually and structurally.

This is a good article, for those interested.

And this is a good one on sill pan flashing with tape.

Are some windows made with integrated sill pans?

What about the bottom nailing strip - does it not get attached to anything?

Kristi the link you presented was interesting to read for pans. It be nice if it is installed that way but I never see a pitched and dammed sill, but the detail is done here for the membrane but not executed as nice. The bottom nailing flange I am guessing would be shimmed to leave a gap for drainage or notch the flange in areas for the same.

I was talking to my uncle the builder about this, and looking at the site about tape flashing a sill...and I don't buy it. I'd like to see how things stand in 20 years after people have started doing this as a matter of course. Just looking at the figures makes me think it's a crazy idea as they have it shown.

- the nailing flange can't get in the way of the drainage. So how is the bottom of the window secured? The nail holes are about 4" apart, if my memory serves me well. There's not much room for shimming, and unless the leak is really flowing the moisture will have trouble getting out because of surface tension. The flanges aren't always very wide, so there's a limited vertical gap between the bottom of the window and the sill plate allowing any nailing anyway.

- there is nothing supporting most of the bottom of the window. The area that will get the most stress is hanging in midair. It's installations like these that cause failure and leakage.

- all that space under the window can't be insulated.

-the water ends up draining behind the siding

- having the bottom not secured and taped is creating another route through which water can enter the wall.

- what percentage of windows installed without sill pans don't have any problems if the rest (siding, trim, moisture barrier, etc.) is installed correctly?*

In the end, install per manufacture's directions for the windows and house wrap.

My 2 cents.

*Reminds me of some windows I came across today from 1921. The sill flipped up and inside, and below was a pocket allowing both sashes to be stored in the wall. Pretty nifty system.

I was just looking again at Mark Parlee's photos and posts. It appears to me that it wasn't improper detailing not allowing drainage that's the problem, it's that the detailing is improper. The corner tape is lapped wrong, the tape isn't applied properly generally, leaving a gap behind it right where it needs most to be sealed...who knows what other dumb things they did, or whether a sill pan would have helped? Could it have been water getting in through the poorly taped corner? I can just imagine it running down the edge of the window and under all that tape. Even looks like there's a hole there. A sill pan wouldn't have helped in that case.

Kristi
A properly detailed and drained sill and would have protected this assembly.
Our current slightly sloped and drained sill pan detail works well but the problem is we dam it backup with some of our exterior trims that are applied at the lower edge of the window. The first two pictures in post #26 show this result.
The window was taped in tight on all four sides; no water came in at the perimeter where it was taped. Had the window not leaked itself at the lower miters this damage would not have occurred. The water came in at the lower frame miters because the sealant was missing from the original assembly of the window at the window was manufactured.
This moisture was incidental in nature not a flood but I can fill a big container with incidental moisture if it will not drain.

I covered a lot of this info in my prior posts but sometimes you have to see it to get am understanding of it. Suffice it to say a properly detailed and drained pan would have handled this problem.
You are welcome to call me if you have questions. I have a lot of data for your insurance companies.
I am currently on a 20M$ building 9years old that has an incredible amount of damage from moisture intrusion that could have all been prevented if correct detailing of the exterior cladding, flashing, and WRB had been followed.
The home in the above post settled in mediation but no one is really happy. I go by projects everyday where the same things that got this one into trouble are still being performed the same way.
I just reviewed 23 homes in a neighboring state that have been constructed in the last four years. 18 of them have elevated moisture in the interstitial wall cavity at the AMV (faux stone).
The AMV problems will make The EIFS problems look like a tiny drop in the bucket over the next few years
Here is more of the same home. Lack of as kick out detail caused this damage.
Found worms in the wall sheathing 6’ above grade.

Moved off topic a little but moisture intrusion is damaging whether a window detail or poor flashing detail elsewhere

I think I'm being a bit stubborn, making vast generalizations like "I don't buy it." I'm sure there are well-designed and -installed sill pans out there. I just think it's a mistake to say that just because one is installed, everything will be ok. There are issues like drainage that have to be addressed without compromising the integrity of the window installation.

The window was taped in tight on all four sides; no water came in at the perimeter where it was taped. Had the window not leaked itself at the lower miters this damage would not have occurred.

It's not taped as it should be. It doesn't look like the sill was taped at all, and that alone might have saved it. So much comes back to faulty work and/or products, doesn't it?

I have a lot of data for your insurance companies.

I'm interested to know what kind of data you mean.

Kristi
The window in the pictures above was taped in at the perimeter so well that no water got in at the edges at all.
The sill pan is a backup if/when the window leaks. Some windows will not leak and others; well it is just a matter of time. In this particular case the window was completely sealed at the perimeter and it held the moisture in that leaked at the frame miters A sill pan would have just allowed the moisture to collect to a higher level and the damage would have showed up someplace else. This pan would not have been able to drain.

As I said in the last post the moisture is incidental in nature, the sill pan is not going to have to deal with a flood of moisture.



It is important to have these sill pans properly drained as I stated earlier. If we don’t provide a drain to daylight toward the exterior then the sill pan has the potential to store the moisture to a level that will rot the bottom of the window as was some of the damage on the window in my pictures.
I have forensically evaluated a few windows like this and the failure to drain is a key reason for this damage to spread so far into the frame of the assembly.



I noticed your signature line regarding house data for insurance companies.
The data I have would be in the form of pictures showing all of the failures I have seen in homes and buildings regarding moisture intrusion into the building envelope due to poor details with cladding and flashing installation.I have hundreds, no thousands of photos showing moisture intrusion damage due to poor workmanship.


I am sure some of the other members have a significant amount of photos showing this type of damage as well.
One advantage i have is that I am around to document the removal of the cladding, the damage under it, and the remediation process with the new details that will prevent a re-occurrence.

Originally Posted by Mark Parlee

Kristi
The window in the pictures above was taped in at the perimeter so well that no water got in at the edges at all. I understand, but still, it was taped improperly. When you install without a sill pan, you should at least tape the plate and a little way up the trimmers. Keep the water out of the wall, even if it starts seaping elsewhere.
The sill pan is a backup if/when the window leaks. Some windows will not leak and others; well it is just a matter of time. In this particular case the window was completely sealed at the perimeter and it held the moisture in that leaked at the frame miters A sill pan would have just allowed the moisture to collect to a higher level and the damage would have showed up someplace else. This pan would not have been able to drain. Yes, I understand all that. And all I'm really saying is that one has to be careful not to create new problems by fixing old ones.

As I said in the last post the moisture is incidental in nature, the sill pan is not going to have to deal with a flood of moisture.



It is important to have these sill pans properly drained as I stated earlier. If we don’t provide a drain to daylight toward the exterior then the sill pan has the potential to store the moisture to a level that will rot the bottom of the window as was some of the damage on the window in my pictures.
I have forensically evaluated a few windows like this and the failure to drain is a key reason for this damage to spread so far into the frame of the assembly. Yes, exactly, and not all windows were developed with these things in mind, so they weren't made to be installed in a way that allows free drainage and secure attachment.

I'm lucky that I worked with such a conscienscious, knowledeable, smart guy and learned to do things well, I believe. Since we did all the stuff, we never had to deal with others' poor work, or take steps to anticipate it - that would've driven both of us mad. That's the perspective I'm coming from, so maybe I'm a little defensive, having been told twice in this thread my window installation was "totally incorrect."


I noticed your signature line regarding house data for insurance companies.
The data I have would be in the form of pictures showing all of the failures I have seen in homes and buildings regarding moisture intrusion into the building envelope due to poor details with cladding and flashing installation.I have hundreds, no thousands of photos showing moisture intrusion damage due to poor workmanship. There's a lot of it out there. Personally, I think it would be great to have more photos on the training modules (which I still refer to), or in a gallery somewhere on the site. I'm writing a letter to my employer's training coordinator, and I'll mention your offer. Thanks! That's very nice.

I am sure some of the other members have a significant amount of photos showing this type of damage as well.
One advantage i have is that I am around to document the removal of the cladding, the damage under it, and the remediation process with the new details that will prevent a re-occurrence. A sequence like that would be interesting to see, start to finish - I'd like to know the details of how drainage is handled. I've replaced a few windows that were rotten below, but no where near what you've seen.

Merry Christmas!

Merry Christmas to you.
I am in Des Moines.
I have a talk coming up in Cedar Falls sometime in January.
Email me and i will let you know the particulars as they develop