Window Supplemental Sealant Experiment
The homeowner had limited choices other than total window removal and reinstallation of another window brand. The homeowner sought to find an alternative (lower cost) fix to the leaking windows resulting in his sealant experiment.
The first attempt was to seal the large gap existent between the window panel frame and the window wall frame, number 1 in the picture below. This effort attenuated the leakage, but that is all, the windows continued to pass rain water.
The red line originally encompassed the entire four sides of the panel window and later reduced to the three sides as illustrated. He used 1/2 inch round foam seal backer, a good indication to the size of the gap designed into this component panel window, that was further sealed on the outside with 50 year clear caulk. There was some attenuation but not elimination of leaking rain water after the gap was filled on three sides. This effort did stop the top sill panel leak of the lower windows but not that entering through the glass to frame gaps.
It was during the third window test. The window test conducted by the window manufacturer's contracted home inspection company that the inspector suggested we open up the two sealed widows at the bottom edge, #4 and part of the corner at #5, and apply more sealant to the window glass at the panel window frame, the blue line #2. His recommendations proved valid.
The homeowner followed his ideas at first seeking the less work option of opening the bottom gap and found that alone did not stop rain water penetration. Once the homeowner added caulk along the glass face (the blue line #2) at the joint of the glass and its frame did all water penetration cease. This was the last piece to understanding of this window design bellowing in the wind effect separated the glass to frame seal allowing water to enter the house.
At number 3, the upper corners of the panel window is highlighted in the picture below.
What is showing is that the homeowner filled in the entire gap to include the window panel horizontal and vertical frame joint seen as the vertical seam at left. The casement window at right was left unsealed so it may continue to be opened as designed.
Key at this point in this window's design is to leave the bottom edge of the top horizontal window panel frame open to drain as the window design does allow water penetration behind the aluminum cladding. Even with the top gap sealed firmly the concern is that over time the continuing bellowing effect may work this seal lose and allow water to enter. This part was well explained by the window manufacturer's contracted window inspector to the homeowner.
The window glass to frame caulking (picture above) was also stopped just short of where the side frame runs up to the top. This is to insure the top frame drains.
At point 5 the homeowner also followed the window manufacturer's contracted window inspector instructions and left open the drain areas that are designed into this window to remove water that again by design is permitted to pass behind the window aluminum cladding onto the interior wood window frame and then pass out through the window panel bottom. That is if the earlier noted window defect of the panel sinking in its frame and crushing the rubber tubular seal does not seal off these drains.
Notice the same vertical to horizontal frame cladding seal at the bottom corner as at the top. The one at the bottom on the face side was left open to further enhance the internal water drainage. Also notice the level of clear caulk applied to where the window glass meets the frame. This is another indication of the size of the gap created by the glass bellowing in the wind and working apart the 3m glass to frame seal.
The glass to frame caulking is contiguous along the bottom and sides. The clear caulk shown in the picture below is that of the homeowner applied sealant into the gap created by the bellow effect.
At numbers 5 and 6 shown here are several more points to consider.
At #5 where the vertical 1/2 caulk backer covered with sealant stops short of the bottom horizontal frame to insure draining of infiltrating water.
The next point is the lower horizontal gap in the window panel to window wall frame is left open to insure water drainage. Part of the crushed round tubular seal can be viewed as compressed by the sinking window panel at right in the corner.
The final point #6, is one of the troubling corner joint failures that recur in the panel and casement windows. This would be identified as a warranty fault by any reasonable person and all that have seen it agree.
This final picture is point 4 of the top picture highlighted in the picture below.
This picture is the bottom window panel frame to window wall frame gap left open with the hopes that any water that infiltrates past the homeowner applied caulk will drain out.
This extra window caulk is not a permanent repair. The issue remains these double pane glass panel windows bellow in the wind. That bellowing effect will work this additional sealant lose to gap just as it did the original factory seal. These windows will require at least annual checks and maintenance of the caulk line. All of this should not be required if the windows did not have these design failures.