First, we need to find out what’s behind the wall before we knock a hole in it. Walls can hide anything from plumbing pipes to electrical wires. If these needful items are in the wall, the window might need to be built somewhere else or the wires and pipes will need to be diverted. Installing a window is also a two person job as windows are heavier than they look.
The framing for a window is made of a top plate, a header cripple studs above the header and below the sill, king studs, a jack stud that supports the header, a sole plate at the bottom and a top plate.
After it’s determined that there's no plumbing or wiring in the wall, the professional will install the window from the inside out. First, he’ll mark the opening and cut from the ceiling to the floor along the studs but leave the sole plate intact. Then, he’ll carefully remove the studs and nail two by fours to the studs on either side of what will be the window opening. These two by fours are called trimmers and they’ll support the window’s header. Then, the header is built and installed on top of the trimmers. After that, the window sill is installed and supported by cripple studs. A two by four is then inserted between the header and the sill. These frame the side jambs.
After this, the exterior sheathing and siding are cut out of the wall. The window is put in place from the outside. The worker will insert shims to make sure that the window stays level, square and plumb then nail the window to the framing through the exterior casing and into the studs. Then, more shims will be inserted from the inside and the jambs will be nailed to the studs. Our worker will then insert insulation between the frame and the studs and refinish the interior wall. After that, he’ll attach the window’s inside casing, then caulk the interior.