Make sure you measure to the framing right next to the old door jamb.
Studs around sliding glass door.
Find wall studs above and below doors and windows.
How to hang curtains over sliding glass doors.
Sometimes these are two by six studs turned on edge.
When hunting for wall studs usually the goal is vertical studs.
Above windows and doors are doubled up studs called headers.
If you re using a zircon or similar studfinder and initiate the scan with the tool held above the door it will register no density change and indicate a no stud condition.
The studs that surround the door frame will extend to the top plate top of wall.
Pull off the interior trim around the old door and measure the rough opening width distance between studs and height floor to beam.
Initiate the scan 8 adjacent to the doo opening and move the tool to above the door.
If this is an exterior door there s likely a solid header above.
There is typically around 1 2 of dead space between the wood of the door frame and the actual stud.
But there are also horizontal framing members located above and below door and window openings.