Check before ordering
Have the opening, supporting surfaces and measurements assessed before the order becomes final. Discuss existing damage, sills and access to the work area. Establish who handles preparatory repairs and what must be ready before installation can begin.
Execute the joints
Fixing, insulation, airtightness and weather sealing need to suit the construction. Ask for an explanation of the proposed installation detail. A general product description does not tell you how these tasks will be carried out at your home.
Handover together
After fitting, check opening, closing, hardware and visible finishes. Request operating and maintenance instructions and record any matters that still need attention. Confirm the service contact and how any necessary adjustment will be arranged following installation.