Measure the gap and cut a piece of the casing to size with a coping saw. Color the piece with a stain marker, apply glue to it and tap it into the gap under the casing with a hammer. If there's a slight line where you can see the joint in the casing, use a putty crayon to color it..
Besides, should there be a gap between baseboard and floor?
No floor and molding will be completely level over really long rubs and shoe covers the gap. It's been said to death, but that's what 1/4 round (or base shoe) is for. It hides the gaps between the baseboard and the floor. You can find something nice that goes with the feel of the house to put in there.
Beside above, how do you seal a gap between baseboard and floor? Install Quarter-Round or Shoe Molding Instead of caulking the bottoms (the floor-to-baseboard junction), nail thin strips of quarter-round or shoe molding. This trim is flexible enough to conform to gaps, even those intermittent sags between joists.
Furthermore, how do you fill the gap between baseboard and tile?
Use the blue tape to cover the baseboard. Use the cardboard roll to leave a tiny gap at the bottom of the baseboard for caulking. After the grout dries, cover it with blue tape and use some latex caulk at the bottom of the baseboard.
How do you fill gaps in trim?
Stick painter's tape above and below the gap for easier cleanup. Remove the tape immediately after applying the caulk; don't wait for the caulk to dry. Caulk that is 100 percent silicone can't be painted. Seal the tube of remaining caulk with a waterproof wire nut, duct tape or a golf tee.
Related Question Answers
Should you caulk between baseboard and floor?
In general, caulking is a fairly cheap and easy home improvement project. However, it has its limitations. Caulk is useful for sealing small, thin gaps between baseboards and the floor or wall. It's also worth noting that baseboards should not be caulked when the floor or wall is unfinished wood.How big of a gap can I fill with caulk?
Measure the size of the gap that needs to be filled. A single bead of caulk can fill gaps up to 1/4 inch. If the gap is slightly larger than this, fill it with a bead of caulk deeper into the gap, but not flush with the surface.Should skirting boards touch the floor?
If laying a laminate type floor you should always leave a gap between the new floor and the skirting, it should not touch or go under skirting boards. You can then use beading to cover this gap if need be.How do you fill the gap between cabinets and ceilings?
Fill in the space with trim If the gap between your upper cabinets and the ceiling isn't particularly large, you can fill it in with trim running along the top of your upper cabinets. This makes for a cohesive, built-in look, and a lot less potential for collecting dust. 
