Timber door frames have been commonly used in homes for decades
. The timber used will range from soft to hard wood. The size of the frame is from six inches to about one foot wide. The thickness is about two to three inches. The size depends on the location and the desire of the home owner. When the door is external, a more robust frame is used. This in particular for the heavier panel doors. The flush or hollow core internal ones uses a moderate frame for hanging the door.
In modern times, timber door frames are anchored into the wall differently. This can use the lugs, dowels, hoop iron or bolts. The lugs are normally small pieces of strong gauge sheets with fish tailed end. They are about six to eight inches in size. The frames can be rebated or simply plain faced. This again depends on the design of the home and preference of the owner. The frame should have right angles at the corners so as to remain plumb when being fixed.
The door frame opening should be thoroughly prepared. It should have an allowance of a quarter inch maximum on both wall ends. The top of the frame should not carry any wall loads. The door opening should be bridged with an arch, beam or lintel. The frame is usually the size of the wall thickness including plaster or rendering. It must be flush with the wall finish on both sides of the wall. This is at least near the door opening and in particular for external timber doors.
The timber door frame is measured into the door opening. The position for sinking in the lugs is marked. They are then nailed into the frame. Holes of six inches by six are dug into the wall. The frame with the lugs is then fitted back. It is aligned and strong mortar with chippings used to fill in the holes on the wall. The plaster is then made good. After few days the door is then hang. The other methods uses screws that are driven from the door frame into the wall. this methods is used on finished homes or when replacing a door frame.