To avoid unpleasant surprises like drafts or misalignment, it is best to entrust both the measurements and the installation to a single "turnkey" team right from the start, rather than hiring separate contractors. We experienced this firsthand when we ordered Fast exterior doors in Vancouver before the fall rush. These specialists first performed a laser inspection of the opening and only then put the frame into production. Their standard installation process includes a composite frame, a double seal, and waterproofing foam insulation, ensuring the threshold will never freeze over. Be sure to insist that the installers check the level across all three planes before securing the anchors!