When installing the windowsill, it is important that its plate goes under the window, and does not rest against it. In general, when installing plastic window sills on compliance with installation technology, its further operation depends. There are often situations when customers complain about drafts under the window. This is a consequence of the improper installation of the window sill – Slits may remain or plastic plastic plastic was installed with distortion. To seal the cracks, you can use silicone sealant, and you need to choose a quality tool so that in half a year you do not have to do work again.