My house is built on concrete slab, and I have a doorway between a bathroom and bedroom that needs to be closed off. Does anyone have step by step instructions? In theory it's just drywall and 2x4's but I want to do it right, so it won't fall over! Thanks in advance.

 

Welcome to the forums! Closing up is easier than making a hole. You will start by fastening a pressure treated 2x4 across the bottom. Sister two studs and install them in the hole on either side where the door came out. This will allow you to screw your existing sheetrock and the new sheetrock to solid lumber. Install a stud or two between. It would be proper to install the studs at the same interval as the remainder in your house to keep up the 16" OC for future ease of location, but not necessary. Oh, yeah, install another 2x4 across where the header is so you can have something for the sheetrock to screw to as well.

 

Remove the door from the hinges.
Remove the casing.
Remove the side and top jambs.
Proceed as Chandler outlined above.