Cracks in your linoleum flooring are more than just unattractive flaws. They are also passages for moisture, and when moisture gets beneath your linoleum, it can cause not only failure of the material to adhere to its subsurface, but can cause damage to the subsurface itself. As such, it's important to fix any cracks that you encounter immediately. Fortunately, a fix isn't difficult to complete. With a combination of seam sealer and scrap linoleum, you can fix cracks of any size, restoring both the look and the surface integrity of your linoleum covering, usually with under an hour's work.
Clean the linoleum surface and within the crack. Use a piece of cloth dampened in lacquer thinner. Run the cloth over the area, through the crack and beneath the two sides of the linoleum on both sides of the crack. Remove any dirt or other material that can interfere with the crack repair. Allow the linoleum to dry for about 15 minutes.
Repair small cracks that extend only a few inches along the length of the linoleum, and if the edges are still tightly together with liquid seam sealer. Squeeze seam sealer into the crack. Use a putty knife to open the crack fully to the subfloor and work the sealer into the crack with a small paintbrush.
Close the sides onto the sealer. Place a piece of waxed paper over the crack. Run a seam roller over the crack to press it firmly in place. Remove any air beneath the linoleum. Put two or three large books over the wax paper to prevent movement of the linoleum as the sealer dries.
Wait 24 hours before removing the books and wax paper to use the linoleum surface again.
Place a scrap piece of linoleum that matches the pattern of the linoleum over larger cracks. This replaces the cracked linoleum with an undamaged piece. Mark with a pencil an area on the top piece of linoleum large enough to cover the cracked area.
Cut the marked line with a utility knife through both the replacement piece and the cracked linoleum below to create a fitted patching piece of linoleum. Set the patch aside.
Put on a pair of heat-resistant work gloves. Heat the cracked and the cut area of linoleum with a heat gun to loosen the adhesive holding the piece in place. Move the heat gun constantly to avoid burning the linoleum, until the piece begins to lift away from the surface at the sides due to the adhesive bond breaking down.
Turn off the heat gun and peel away the cut piece of linoleum from the floor. Heat the remaining adhesive left on the floor with the heat gun. Peel it away and use the putty knife. Allow the floor about 15 minutes to cool to room temperature.
Brush linoleum adhesive onto the bottom of the fitted patch with the paintbrush. Press the patch firmly onto the floor. Wipe the surface of the linoleum with paper towels if any adhesive squeezes through to the edges to remove the adhesive.
Apply seam sealer to the seams along the patch edges. Cover the patch with wax paper. Run a seam roller over the patched area. Place two or three heavy books along the crack. Wait 24 hours for the adhesive to set. Remove the books and wax paper before walking on the newly patched area.