If installing a log cabin for the first time, door fitting can often result in a question or two regarding how snug the fit is.
Position the door and its frame into the wall recess and chances are there is a gap above the door frame anything up to 40mm. In a similar vein, a door frame positioned centrally in the opening can have gaps either side to the wall logs of between 20 and 30mm.
Gaps of this size are perfectly ok !
The design requires the wall logs to move independently of the door frame. Moisture content within the wall logs will vary according to the ambient humidity. The change in moisture content will increase and decrease the size of the logs by a small amount, but multiplied over the height of the wall can mean difference of up to 50mm.
If the frame strip is not wide enough to cover the gap at the top, please see this article on settling wall logs .