subject: Replacing Bow Windows [print this page] When looking to take out some old bow windows and put in new ones, you first have to build temporary support. These windows are very long; removing them will endanger your ceiling's structural integrity. Place the temporary wall two to three feet from the inside edge of the wall, with studs positioned to support the ceiling joists/trusses. After that, turn off the power for the outlets in the wall.
With a reciprocating saw, cut around the edge of the existing window, slicing through its nails, and be sure to have someone hold the window as you do this; once they're all cut, it could fall. After that, lift the window out and remove the old frame and trim. Next, place the new bottom plate on the floor in the opening. On both sides of the plate, pit in two nailed together studs (also known as king studs). Working from the inside and outside, put the two bow window headers up. Run three lines of 16p nails along them, along the middle, bottom and top, and space the nails twelve inches on centre. At this point, the temporary wall can be taken down.
Nail short studs, known as cripples, into the bottom plate, connecting each to one of the existing cripples. If necessary, trim the existing ones to the same height of the new ones. Then nail the sill to the cripples.
You can now position the new bow windows in the opening, and use blocks or shims keep it in position. Using a level, put shims at sixteen inch distances to hold the windows up, and then drive 10d finishing nails through the shims to attach the window.
Screw the new eye hooks into the outside of the header, loop the cables between the edge of the windows and the nooks, and secure them to make the window above level slightly. Over time, it'll settle into position. Tighten the sill to the window bottom, place insulation along the top, enclose it, and then attach the flashing to the bottom and sides. Finally, put the trim work on the inside and outside.
