Baseboards tend to be straight and inflexible, yet floor coverings often are not. Sags between joists are common in older homes, and even in new installations, it can be difficult to get the floors perfectly flat and smooth. How to fix this gap?
Sometimes, homeowners and even installers will inject caulk in this space. Caulked baseboards are usually preferable to gapped baseboards that are unsightly and permit energy-wasting drafts, but they are still not the most elegant solution. Installing quarter-round or shoe molding is a better option.
Baseboard molding installations are very often finished off with an additional thin piece of molding called quarter-round or shoe molding that covers the gap between the bottom of the baseboards and the floor. It's an easy installation that costs little and gives your floors a precise, polished look. Carpenters like to use these bottom trim pieces because they reduce the need for complicated baseboard scribe cuts.
What Is Quarter-Round and Shoe-Molding Trim?
Either of two types of molding can be used: quarter-round or shoe molding. After installation, both will look similar, though their profiles are different.
As the name indicates, a quarter-round molding, when viewed from the end, will appear to be one-quarter of a full circle, with both flat faces the same width. The length that the quarter-round protrudes from the wall is the same as its height.
Another way to think of quarter-round molding is to imagine a round dowel. From the end, the dowel is cut into four pie pieces. Each resulting piece would be a quarter-round.
Shoe molding, at first glance, appears to be the same as quarter-round. Yet when you look at shoe molding from the side, you can see that its height is greater than the length that it protrudes from the wall. The reduced protrusion affords a bit more flooring room and gives the trim a more finished look: it appears to hug to the baseboard.
Uses for Quarter-Round and Shoe Moldings
Both quarter-round and shoe moldings are long, flexible lengths of wood such as hemlock, oak, or pine, MDF, or even polystyrene. Both trim moldings start as long round dowels that are then rip-cut and milled into their respective shapes.
Both types of molding are stocked in very long lengths, racked vertically at the home improvement store or lumber center. This extra-long length is so that you can use full-length pieces to cover most walls. Although you can join shorter pieces to cover a long wall using scarf joints, most carpenters try to avoid this since full-length pieces give a smoother look.
Shoe and quarter-round moldings are quite flexible, intended to bend and conform to the floor profile. Don't worry about buying perfectly straight pieces; they can easily be bent into place during installation.
This installation features both inside and outside miters to join pieces of moldings at the corners. This requires you to cut the ends of the moldings at 45 degrees to make the 90-degree corners. This installation also demonstrates how to cut and install a return: a small piece that finishes off an exposed end of the trim.
Equipment / Tools
- Tack cloth (optional)
- Tape measure
- Power miter saw or handsaw and miter box
- Brad nailer
- Nail set
- Quarter-round or shoe molding
- Paint, or stain and varnish (optional)
- Sandpaper (optional)
- Wood glue
- Painter's tape
- Wood putty (optional)
Pre-Finish the Trim (optional)
Most finish carpenters like to finish the long trim pieces before measuring, cutting, and installing them—either by painting or applying stain and varnish. This is considerably easier than trying to finish the quarter-round or shoe molding after it is nailed in place. Some touch-up work will be needed after the trim is installed, but this can be done with a brush.
Make sure the moldings are clean and smooth by giving them a light sanding. Run a tack cloth down the length to remove sawdust. Apply the paint or stain, as desired. With such small moldings, wiping on the stain with a rag is often the easiest method.
If you do choose to stain your moldings, make sure to choose a stain-grade hardwood base-shoe or quarter-round molding, preferably the same species of wood as your baseboards or floors. Pine or other softwoods are good for painting but do not take stain very well.
Once the stain has dried, apply a top-coat varnish, following the manufacturer's directions. Let the finish dry completely before proceeding to installation.
Measure and Mark the First Trim Piece
Instead of trying to measure, mark, and cut all pieces before nailing, it will be easier to avoid mistakes by measuring, cutting, and installing the trim one piece at a time.
If you are beginning with a piece that will fit an outside corner, such as around a post or wall arch, you can position the piece of molding across the wall and mark the ends of the molding with a pencil at the wall intersection. If you are installing base shoe molding, make sure that the long edge of the molding is upright against the wall.
Make a light angle mark to show the general direction the miter cut will make—it does not need to be precise. The purpose of the mark is simply a reminder to yourself of the general direction of the 45-degree cut.
If you are beginning with a piece of molding that will fit inside corners, measure the full length of the wall and mark a long piece of molding to these dimensions.
It's ok to cut pieces a hair long if you're using a power miter saw, which can shave off a tiny amount of wood cleanly. If you're using a handsaw and miter box, it's best to get the length right on the first cut because fine adjustments are difficult.
Miter-Cut the First Molding Piece
Set the handsaw or miter saw blade to 45 degrees. Position the trim piece on the miter box or saw base so the blade just touches the pencil mark. Make sure the blade is to the outside edge of the pencil mark, preserving the mark. It is very easy to cut too short if you cut through the mark itself. Make the first cut. Reverse the saw to 45 degrees in the opposite direction, then cut the other end of the trim at an opposite 45-degree angle.
Test-Fit the First Piece
Position the first cut piece of trim in its wall position and check its length. If it is slightly too long, you can take a thin kerf-cut slice off one end of the molding to make it fit exactly. Do not fasten the first piece yet as it needs to be movable until you cut the second piece.
Cut the Second Piece
Measure, mark, and cut the second piece of trim. Make sure to cut the angle correctly so the piece will correctly meet the miter angle of the first piece.
Test-Fit the Second Piece
Set this second piece of trim on the floor and check its length, as well as its fit with the first piece.
Skilled carpenters, when faced with corners that are slightly out of square, are able to adjust the angles of the miter cuts to make the trim pieces fit exactly. For example, if an outside corner is 94 degrees rather than 90 degrees, making the trim miters at 47 degrees will create a perfect fit. Do-it-yourselfers, too, can experiment with different angles (by using waste trim) for a perfect fit.
Nail the First Two Pieces, and Continue
Position each piece of trim and fasten it with a brad nailer or by hand-nailing with a hammer and nail set.
The preferred tool for nailing shoe molding or quarter-round is an electric finish or brad nailer. This tool will automatically set or recess small finish nails, and can greatly speed up your work. To use a nailer, first calibrate the depth of the nailer, using a piece of waste trim on another waste board. With the depth perfect, drive the finish nails or brads about every 18 inches. Hold the nailer close to horizontal, but angled slightly downward. Hold the trim tight against the floor and baseboard as you fire the nailer.
If you hand-nail, drive each nail almost flush with the wood surface, then tap it in just below the surface with a set and the hammer.
Continue measuring, cutting, and nailing trim pieces around the room, one piece at a time.
Create a Return Piece to Finish the Ends
A return is a small piece of molding that neatly finishes off the end of a piece of quarter-round or shoe molding where it ends without turning another corner. It is not necessary to cut a return, but it is an extra finishing touch that makes your work look more professional since it hides the end grain that would be exposed if you cut the trim off straight on the end.
This is the way to lead up to a return:
For the piece that will terminate in a return, lay down a piece of molding that is several inches longer than the length you need. Mark your cut point on the bottom of the molding, not the top. As before, lay down a light pencil mark to show your angle. Cut the piece to a 45-degree angle, then position and nail the piece into place.
Measure and Mark the Return Piece
A return piece is a very short stub of trim that will fit into the angle at the end of the first piece. Position a second short piece of mitered trim against the wall with the mitered end matching the miter on the preceding piece.
Cut the Return Piece
Cutting the tiny piece of return trim can be challenging, especially with a power saw, where the speed of the blade can break the small piece. Instead, you may wish to make this cut with a manual miter box and saw. First, cut the small return piece at a 90-degree angle across its end. Then, test-fit the return piece to make sure that it fits. If not, cut a new return piece.
Glue the Return Piece
Nailing a return piece is not practical, as the wood will split when a nail is driven. Instead, apply a tiny dot of wood glue to the mitered edge of the return piece where it meets the first piece. Do not glue the wall side or floor side of the return piece.
Press the return piece in place so the mitered edges meet, and allow the pieces to sit undisturbed until the glue dries. Taping the pieces down with painter's tape will hold them in place while the glue cures.
Flatten Protruding Nails
Rarely necessary when you are using a finish/brad nailer set to the correct depth, nevertheless finish nail heads will occasionally protrude from the trim.
Pounding the nail head with a hammer will mar the trim. Instead, use a nail set and hammer to lightly tap on the nail heads until they are driven down just below the surface of the trim.
Remove the painter's tape from any glued return pieces.
Touch up the paint or finish on the trim, if necessary. If there are small gaps between the molding pieces where the corners were slightly out of square, you can fill them with matching wood putty. With painted trim, you can use caulk to fill these gaps.