Ugh Pella, agree with Windows on Washington, need to see the exterior detailing.

Here is the best picture I have at the moment. The window pan has been built, tapped over lapping and the tyvek wrap overlapping the flashing tape.

Did the arch top come factory mulled to the single hungs or is that a field mull? And how dies the service tech plan to fix this without pulling the windows?

It was factory mulled. I have a friend that is building another house who is using Pella Encompass series windows and is having the exact same problem as I am with the top transom. It seems Pella has a design flaw in the mull. Just hoping it can be fixed without the windows needing to be pulled

What’s your top and side detail with the house wrap? The flappy tail of the Tyvek on top?

Yes, tyvek is overlapping the flashing tape. Pan under the bottom. It’s done per Pella specs minus the flashing tape on the bottom. I have already took it off and it still pours right in. I’m hoping the mull can be repaired with silicon and fix the issue, but honestly not sure

From far away, the bottom flashing tape could be causing water to collect.

I subscribe to the 'All windows will leak' school and flash the top and sides but leave the bottom unflashed, over a sloped flashed sill pan. Then, air seal from inside.

Just my guess, but still consider more how to let water out, vs. keeping water out.

"It seems Pella has a design flaw in the mull."

I don't know how you would fix that then without a pile of silicone. Another one of many reasons in my opinion to stay away from Pella.

Could be the mull or could be the fact that the bottom flange is taped in. That is a big red flag.

These were installed yourself?

were they factory mulled or mulled in sight? Water is leaking at the mill on top or on the sides? The water is showing up in the inside where?

excellent point by WOW.

Housewrap should be lapped and taped at the joints. Mixing three different types of housewrap on the same house is interesting.

I have removed the tape on the bottom flange and it still poured right in. Worthy the lumber yard ran out of typar and the framer needed to stand the gable up. Both are solid products. Obviously I would have liked to have it all typar. The house wrap is lapped over the tape, just hard to tell. I will tape the joints and see. Pella swears it’s the mull. I think they have had issues, because they went straight to that.

I’m noticing there are 2 separate trays in the bottom. One the sash comes down and sits in and one behind. Water will intrude in the bottom corners fill up the back tray and make its way into the house. There are weep holes on the front tray but none on the back one. Is this normal?

This is what the horizontal mulled joint at the upper fixed window looks like. Any exterior joint that is dependent on sealant/caulk to prevent water intrusion is going to fail sooner or later.

RES, that actually helps a lot. Do you think it’s the mull?

Did you ever find out where and how the water was coming into the interior? I have a similar problem with my window (leaks in driving rain with water coming in at the bottom of the window between the exterior sheeting and the window fin. Have torn out the stucco down to sheeting, rewrapped with both house wrap and flashing tape but water still comes inside at the bottom of the window. Water does not come in at first either. Acts as though some part of the window or wall is filling with water then once the water reaches a certain level the water streams out the bottom. Sort of like breaching a dam.

@karenhine what brand and type windows do you have? Pictures?

No issue with Pella Architect series but it was the WORST buying experience in my life.

With all the data out there...people still buy this brand by the billions

It really baffles me as well Eric..............

Were yall able to fix this issue?

The fold-up or slide-in nailing fins on Pella windows are not water tight so it's necessary to place self-adhering flashing over that joint.

Another potential leak locarion is the top corners espeically with an arch top window.

"Were yall able to fix this issue?"

Jordan Brummett, what is your exact issue?

Im honestly not sure, just have no knowledge on this subject. But in the picture above we have a thin line of water on the floor & it is bigger underneath the right line of the window. Same issue under a window next to this one. There is stone on the outside wall, on top of tar paper and regular house wrap. Trying to get different input on what could cause this?

The water we had came in right at the corners of the bottom sill of the window (left and right sides) and not in the wall. Only had water coming in when we sprayed the upper corners of the window so we assumed the window was not installed and flashed properly. We took out the window and replaced a lot of things...new house wrap, new wider flashing above the window, new stucco and the darn window still leaked. Pella got us a new window after several other failed fixes and we did the same exact things...new house wrap, new flashing, new stucco and no leak. By chance does that side of your house get pounding horizontal rain hitting it when you have bad storms? We only had problems with this one window that just took a beating during heavy rain storms. Sorry I can't be of more help. The Pella rep and my window installer were at my house so many times over the course of last year and they were just as stumped as you are now. If we can figure out what caused our leaks we should patent the solution!!!! Let me know what fixes your leak problem. Good luck Jordan.

Any pictures of the exterior? Pics during construction of the window head before siding? Definitely sounds installation related and most likely lack of improperly installed flashing.

I would first suspect that the flashing tape was not turned up on the frame to seal the nail-fin joint and then the two brands of woven perforated wraps.

Not exactly what I would call 6" of overlap on the WRB. Misapplied on the head tape detail. There are issues there already.

I have no technical/installation input to offer, but I can say that one of my single hung, double panel windows is leaking when there is rain with wind. The window faces a covered patio several feet deep.

It's leaking from the center top, down the blinds and onto the sill and floor (over an electrical wall outlet). The window was installed about ten years ago, and only recently did I notice the issue (I live in the desert and we rarely get rain). The ceiling shows no sign of water damage above the window.

I've had a miserable experience with Pella tech support. One rep actually informed me that the double hung windows "are designed to let in wind and water." I ultimately had the window totally replaced with a single hung version. The next time I needed maintenance, he made the windows function far worse than before.

I don't know what I will do this time except for ask for a different tech. Good luck resolving your issue, I know I need luck to resolve mine!!

"are designed to let in wind and water."

The only explanation I can imagine is that the designers at Pella misunderstood a corporate inclusive/ non-discrimination policy of some sort (yes, I think we can blame this one on HR.)

Stucco is a very unforgiving cladding; you need to get all the details right. The photos are clear evidence that the contractor didn't.

I think the OP has left the Houzz.

Maybe, Mark, but that doesn't mean the party's over.

Haha i am still here, hoping the issue has been resolved but not too optimistic. Will not know until we get some good rain.

We had our first big monsoon storm yesterday, and then it rained through the night. The window leaked like a sieve. I'm wondering if my window has an installation issue, too. The windows are installed in stucco, so perhaps it is a cladding issue.

Sounds like it, probably not flashed properly.

@SA Stephens

Do you have any details showing how the stucco was to be installed where it intersects windows and doors? Any pictures during construction?

We need several outside pictures to make an informed diagnosis.

I have a feeling that even with lots of photos, diagnosing the problem is going to require the removal of some portion of the interior trim and drywall and use of a garden hose.

@Charles Ross Homes @Windows on Washington Ltd

No pictures, this installation was done years ago. I was just weighing in because the OP asked if anyone else had this issue.

My neighbor got the same windows and the installers covered over the weep holes, so his leaked inside through the window frame. I learned from his experience on that, and things held well until now, and only on one window.

I thought I would respond to this old thread in case it could help someone. I don't have technical experience in this field... but I did have 3 very large leaking Pella picture windows in a 10 year old house that I purchased. They leaked during heavy windy rains. I had roofers, siding guys, and window guys come out to make flahing and siding repairs w/o any luck. After dealing with this problem for 6 months another contractor sprayed a hose and could determine that the water was coming in at the window seals. It was evident in windy conditions because the water was being blown upwards and coming through the top seals and then running down the window. The contractor applied a bead of silicone along the seal on the exterior of the windows, 30 minutes later the problem was resolved. Had I known, I would have saved thousands and dollars and a lot of headaches. Years later those windows are still fine but I have had to apply that same bead to other leaking windows to resolve the same issue.

Thank you for the follow up and there absolutely are scenarios where windows will leak as you describe under pressurization. Especially those that are larger and able to deflect more across a larger surface area. This is usually addressed via the careful application of some marine grade silicone. That said, the leak issue above were not glazing related. But your example is absolutely possible and does happen with regularity.

I have the same issue with my Pella windows. When it rains, the rain goes down the window and settles into the window sill. However, it does not drain out through the weeping holes. It drains inside the wall. I ripped out the drywall to locate the issue.

The Pella tech poured water into my window sills to verify where the water was draining. While some water did trickle out through the weeping holes, the majority of the water appeared as a wet spot on the concrete block behind the drywall I had removed. As time passed, the wet spot on the concrete grew the width of the window sill and spread down to the floor.

" The Pella tech poured water into my window sills to verify where the water was draining. "

HU-843215781 , And what did the Pella "tech" suggest or do to fix the issue?

Hi All, about 30 days ago I had 18 windows replaced in my house with Pella Impervia windows (new construction replace). That was about half the windows in the house as I did the front (which is a brick facade) and the driveway side with a wood siding. On the first storm, which was a bad blowing storm, almost every newly installed downstairs window leaked (6 out of 8, depending on how you count some of the windows). The water dripped from the top on most and the side on one. I also noticed water in my basement beneath one of the windows on the brick facade side. They are coming back to "fix the issue" by applying sealant, which I suppose Jeff Manning found did help but I'm worried about somehow it just directing water around the window instead of properly pushing it back outside. Any advice on what I could make them aware of, or what I can do to make sure they are doing it properly?

Sealant will not fix leaking or if it does it is a Band-Aid and temporary at best usually. Pictures of the installation may help us but if that many are leaking from the top I would say the head flashing or drip cap is either not there or not installed properly. Nothing to do with Pella from the sounds of it, yet. This is all speculation as we cannot see the install.

Got it. Really appreciate the response. They are actually re-installing one window because Pella accidentally shipped the wrong one (and they didn't realize it before they installed it), perhaps when that one is installed I'll be able to get some pictures during the process. I can also try and get some when they do the sealant as it will be a bit more opened up than it is now.

" I can also try and get some when they do the sealant as it will be a bit more opened up than it is now. "

Again sealant is the last line of defense, not the primary. If they are leaking that badly, stop them and have them all pulled and reinstalled properly. No other way.

Makes sense to me. Just always hard being a customer that literally knows nothing convincing a builder to do something.

Out of curiosity, I got my moisture meter out and it registered wetness mostly beneath the second floor windows on the brick facade side. 4 our of 5 windows on that floor had 100% moisture beneath it and the same number showed 100% moisture above the window on the first floor windows directly beneath them. Wetness like that didn't show up on the non-brick facade side of the house (although a few of the lower windows were leaking but again, no moisture readings around them registered) and there were no positive wetness readings on the sides of the house with the old windows.

Again, I do really appreciate any thoughts you might have that help me sound more knowledgeable and point them in hopefully a fruitful direction.