Installing Door Moulding

Updating the look of a room with door moulding is a quick way to add style.  If you have some wear and tear around the doorway (from toys being rammed into it, etc.) it's also a good way to give your room a fresh, clean look.  Covering up dings, dents and scratched areas with a beautifully detailed header and pilasters is a wonderful way to correct blemishes while adding style to any room.

If you already have door moulding in place, remove it carefully using a pry bar or crow bar.  Keep in mind that you should be using the pry bar to gently lift the trim away from the wall.  Don't jerk it or push forcefully against the wall itself, as this will damage the wall.  Instead, use an easy lifting motion to pull against the wood, not push against the wall.

Paint your header and pilasters before installing.  It's easier to do this before fastening to the wall and you will get excellent coverage not having to contend with the edges where the door moulding meets the wall and floor. 

Measuring is crucial to proper fit.  Mark a line 1/8” in from the edge of the door jamb.  You'll be installing your moulding flush with this line.  Then measure your door moulding from the top of the sill to the inside, upper corner of the frame and add the width of the header to get the finished height of your door moulding.

Next, you'll need to use a miter saw to cut diagonal joints on the pilasters (the side pieces of your door moulding) and the header.  Cut the miter joints at a 45˚ angle so that they fit together cleanly.  If you don't have a miter saw or prefer a more elaborate look, consider using block mouldings, sometimes called corner blocks, that can be used as joining elements.  These are a simple way to top the pilasters and connect the header without having to cut any angles.

You should always install the header of your door moulding first.  Before nailing it into place (flush with the line marked earlier), check to see that it is level, then check it again.  Nail the header into place with 8d or 6d nails. 

Once your header is securely in place, butt the pilasters up against the header on one side and check to make sure it is plumb.  You don't want the door to look like it's leaning!  This is why you have that 1/8” mark – some doors aren't completely plumb, and you want a bit of leeway to work with.  You can nail the pilaster into place with the same size nails used on the header.  Make sure the 45˚ meets firmly! 

If you've chosen to use corner blocks, install them after the header but before you install the pilasters.  You should have allowed for the size of the corner blocks when measuring for the header and pilaster.  For instance, if the corner blocks are four inches each way, deduct 2” from the header on each side, and 2” from each pilaster so that they will be flush with the corner block, which should be set at the exact corner of the doorway. 

After you've installed your door moulding, use an awl to sink the nails slightly the header, pilasters and corner blocks (if used).  Use a filling material such as wood putty or spackle, depending on the type of door moulding and whether you have stained or painted your header and pilasters.