Installing case molding around the doors after hanging the doors will cover up the edge of the drywall and the wood and shims you have used for hanging the door. This part of the home DIY project is one that is easy enough to do, but you will have to make some cuts to make the two sides and the top case molding fit together. To make the cuts in the case molding you will use a miter box. You will be making a 45 degree cut on the two sidepieces and the top piece so that the pieces fit together neatly.
Things that you will need:
• Miter box or saw
• Nail gun (optional) Hammer will do
• Tape measure,
• Penny nails
• Center punch
Measure the sides for the length of casing molding you need. Then measure the top for the right size piece. Cut the three pieces you will need to close up the doorframe. Standard heights and widths may vary, but this is for an eight-foot high doorframe by four feet wide.
Stain the case molding before putting it on the doorframe. This is the easiest way and saves time. This may take a couple of days depending on how many coats you will be doing. The wood case molding can be stained or painted depending on your preference.
Take the top piece of case molding and place it on top. Make the mark on the wood where the corner of the doorframe is. This is going to be your cutting start in the miter box. Do this on both sides of the doorframe.
You should use a level to make sure the case molding is level. You can use a penny nail to hold the molding up. Place the piece in the miter box and make the 45 degree cut.
Place the two sidepieces up and hold them with one-penny nail. Use the level to make sure they are level and mark the top corners of the doorframe on the case molding. Remove each piece and place in the miter box and make the 45 degree cuts on each piece.
Tack in the sidepieces and then add the top piece. The corners should be perfect. If everything looks good, you can add the rest of the penny nails using a level to keep everything straight.
Use the center punch to sink the penny nails. This is done very lightly as to not sink the nail too far. After the nails are sunk, add a little wood putty or chalk and then stain that area and you are done.
These steps are for straightforward pieces of case molding. If you use different types of case molding, the installation will be a little different. Colonel case molding has a few more steps involved. Any case molding can be used, but make sure that it matches with the rest of the interior case molding that you have around the windows and doors.
The exterior doors can be done the same way, but then again there are a few more steps to take because these pieces will be outside and need to seal the doorframe from the elements. Insulation is usually stuffed inside the doorframe where the shims are located to stop any drafts from getting through.