Revisions log for Answer #3029

This profile is used because of the small size of the window sill in buildings where the installation of the sill was completed much earlier. Especially in buildings where cladding is used, window sills or balcony sills are not long enough and drip trays may be closed when the insulating material passes in front of the sill because of the thickness of the board used. In such cases, PVC or aluminium sill extension profiles are used to prevent damage to the system and to drain the water safely.

In buildings with thermal insulation, PVC sill profiles are used to prevent thermal bridging with the insulation board. Another purpose of the extension profile is to prevent water from getting under the cladding.

Typically, 3 types of sill extension profiles are used:

Aluminum Sill Extension Profile: The installation process is accomplished by applying electrostatic paint to the surface of the profile, the raw material for which is aluminum.

PVC window sill extension profile: Also known as standard window sill profile, this is the most preferred extension profile from pcv raw material.

Sill extension profile with aluminum backing: Unlike the standard profile, it has a screw-on backing. It is screwed to the facade just before the cladding process begins, and the insulation board must sit on this screwed part.