Jamb extension is a groove on the inside of the frame where you mount an extension as the wall often is thicker than the frame. The groove for a Jamb extension is an option and is not standard on our doors.
If you want a door with a side light, we build this in the same frame. The design is better and it gives more daylight as you only need one mullion. The door section also becomes easier to install. We can build a door and side light in the same frame up to size 20x21M
A black-painted wooden door gets incredibly hot if it is in direct sunlight. Wood is a living material and a door that is black becomes so hot that the door leaf can warp and then you can have problems with the opening and closing the door correctly.
Our exterior doors are painted in any NSC color with Jotun Optimal Window and door. However, we do not recommend dark painted doors in sunny locations because the exterior door can get extremely hot and you can get troubles with opening/closing the door.
No, we do not make veneered exterior doors because we know that a veneered door is extra sensitive outdoors. We only make solid exterior doors and doors with solid panels. We build exterior doors for our own climate on the Swedish west coast and doors that are “maintainable”.