Wood under entry door rotted

[JayCee]

The wood under my entry door, the part that you step on and also the wood that is under that part that it sits on is rotten and I can see through it into my basement. I am guessing this is called the threshold but not sure. I don't know how to go about replacing it. I am thinking I have to remove the door and also the wood pieces that the door is hinged to in order to better expose the portion on the bottom that needs to be replaced. Is that how I should go about it and what might the dimensions of the wood be 2x4,2x6 etc ? It is too rotted out
for me to measure. Is the wood just nailed into place and would it be a good idea for me to cover the vertical piece that the other piece that is under the door is on top of is attached to with a piece of metal to prevent future rotting? Thank's in advance for any helpful advice offered.

[HayZee518]

the threshold is the part directly under the door. it sits on the subfloor which in turn is nailed onto the plate and joists. the bottom plate is bolted to your foundation. the door frame is nailed into your "jack studs" on either side of the door jamb. if your plate is rotted you should cut it out or at least open up your outside siding to see how far back the rotting has progressed, cut it out and replace it with a pressure treated product. the reverse build to get everything back the way it was.

[JayCee]

Thank you for the quick reply..I will cut out the rotted wood and replace but I am not sure what size wood to use as it is so badly rotted that I cannot measure it accurately...is there a common size for a threshold and plate, such as 2x4 for the plate and 2x6 for the plate? As far as I can tell it is not rotted beyond the width of the door itself...

[HayZee518]

dimension lumber is a 2x4, 2x6 or 2x8 rarely have I seen a plate larger than a 2x8 stair stringers are 2x12.

[JayCee]

Thank's again for another quick and informative reply...I should be able to
get started early next week...It will be nice to see that rotted wood gone and hopefully the draft under the door and into the basement as well.....