I just spent my Friday evening at a finished home where most of the windows have problems opening and closing... I can fix the problem, but we did not create it. When I try to explain all I get is "don't make excuses"... Goodness ... you have to trust someone, especially if you know nothing. (BTW, the builder will happily pay to have this fixed too...)
So you don't give your window supplier a hard time... the 3 most common causes of windows and doors not opening or closing, or sticking (binding), occur during installation are...
- Problem 1) Installing the window out of square, or bricklayers levering the window after installation to suit the brickwork (which with a little effort could be adjusted during laying).
Problem 2) The absence of packers, or the failure to put them in the right place. All windows and doors are installed into brick veneer construction by nailing into the timber frame - but there should always be packers (usually masonite) between the timber window reveal and the timber house frame. This is CRITICAL under a mullion (inner vertical member) where a heavy window (double glazed or maybe 2m x 1.8m) can easily bend the reveal and distort the openings, causing the sashes to bind.
Problem 3) Bricks compressing the jamb (side of window/door or outer vertical member). The bricklayer using the slightest force in laying up to a jamb can distort the jamb in the middle, again causing binding.
Not excuses - reality. But the binding can "usually" be fixed post construction by the window supplier, but it's not a window problem.
If you are keeping an eye on your build, watch out for packers...