Here’s a challenge: I’ve installed 3 Anderson 45degree bay windows, 2 fifteen years ago and the third seven years ago all in the same home. I learned the hard way, in spite of Anderson’s suggestion to use their cable system, to carry the weight of the window back to a soffit or header via these tension cables is inadequate. I might add these are large units at 6 and 9 feet long by 5 ft. tall approx.
What has happened in the first two is that in spite of the cable suspension system, the side windows’ jambs have racked binding the sashes and making them inoperable so much so its a wonder they haven’t broken the glazing. Also, the interior walls have some hairline cracks at the ends of where the rough header and sills meet their studs. I’ve rechecked the installation instructions. and nothing’s out of line including doubled studs, glued and nailed headers, double top plates without any joints within reasonable distances. Still, my engineering sense was always suspicious and has proved right.
The third window I installed with extra detail to the rough framing and we added a load-bearing enclosed kneewall under the window without cabling above. This window is stress-free and 100% operational.
Now, the $1M question. Short of completely removing in reinstalling the first two windows, to remedy the racking I’m suggesting:
– Adding a supporting knee wall outside. The window’s bottom platform should be slanting down from the sill thereby the outside mullions only should contact a level kneewall providing support against further sagging but leaving space at the wall for the platform to settle down.
– Removing the interior casing trim. Cutting the fasteners anchoring the side jambs, upper and lower platforms. The cables above still tie the window back into the header and were installed to strong enough to carry the full load of the window.
– Then, hopefully the frame at the wall side of the bay will drop or can be encouraged to drop, to relieve the racking on the 2 side sashes.
Sound like a plan? Any insight or suggestions are welcome.