Replacing part of door frame

[wijcc]

Is it possible to replace part of a wooden door frame? The lower part of the door frame on one side has become rotten from prolonged damp/wetness, can I remove the damaged section and replace it with new treated wood or would I need to replace the whole section?
The complete door frame has glass pane above the door. I have fixed the source of the damp/water.. so it should not be a problem again.
Thanks in advance

 

[Deleted member 174758]

Yes. This used to be quite a common repair at one time. Use a scarf joint angled so that the highest point of the scarf is on the inside of the frame

 

[wijcc]

Thanks for replying.. how thick wood would i need to purchase to make the new door frame part? What is the usually thickness of external door frame.. would it be 102.5 or 215mm thick i.e the width or length of a standard size brick please?