Replacing old wood baseboards with PU baseboards is a common renovation project, and the project can be completed in a day for a single room with basic tools. The new PU is more durable, more stable, and easier to maintain than the old wood, and the result is a room that looks and feels fresh.
The first step is removing the old baseboards. Carefully pry the old baseboards off the wall with a flat pry bar, starting at a joint and working along the length. Place a thin piece of wood behind the pry bar to protect the wall from damage. Pull any nails or screws from the wall, and remove any remaining adhesive or caulk.
The second step is preparing the wall. Inspect the wall behind the old baseboards for damage — nail holes, gouges, loose paint. Fill any damage with patching compound and sand smooth. Wipe the wall clean with a damp cloth to remove dust. The new baseboards need a clean, sound surface for the adhesive to bond.
The third step is measuring the new baseboards. Measure each wall, and cut the new baseboards to length with a miter box and a fine-tooth saw. The outside corners are mitered at 45 degrees, and the inside corners are coped (for a traditional look) or butted into a corner block (for a simpler install).
The fourth step is dry-fitting the new baseboards. Place the new baseboards on the floor against the wall, and check the joints for fit. Any adjustments are made before the adhesive goes on. The dry-fit is the difference between a clean install and a chaotic one.
The fifth step is installing the new baseboards. Apply a continuous bead of construction adhesive to the back of the baseboard, press it to the wall aligned with the layout marks, and drive a few brad nails to hold it in place while the adhesive sets. The joints are filled with paintable caulk.
The sixth step is finishing. After the adhesive has set, set the brad nail heads below the surface and fill with paintable filler. Sand any rough spots. The painter's topcoat goes on the next day, with the baseboards finished in the same color as the other trim or in a contrasting color.
A practical note on the floor. If the floor is being replaced, the new floor goes in first, and the new baseboards go on after. If the floor is staying, the new baseboards can be installed on top of the existing floor, with a small gap at the bottom covered by a matching shoe molding.
A practical note on the shoe molding. If the old baseboards had a separate shoe molding (a small strip at the bottom that covers the expansion gap between the floor and the baseboard), the new PU baseboards should be installed with a matching PU shoe molding. The shoe molding is the finishing touch that makes the install look professional.
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Frequently Asked Questions
Q: What is polyurethane (PU) decorative material?
A: Polyurethane (PU) decorative material is a high-density closed-cell polymer molded into architectural profiles such as cornices, ceiling medallions, wall panels, columns, and skirting boards. It replicates the appearance of plaster, carved wood, or stone at one-quarter the weight, is fully waterproof, impact-resistant, and arrives factory-primed for paint.
Q: How does PU compare with plaster and wood mouldings?
A: PU is lighter than plaster (no scaffolding required), impact-resistant during transport, and immune to cracking. Compared with wood, PU does not warp, split, or attract termites, and it tolerates moisture in bathrooms and kitchens. The trade-off: PU cannot be refinished the way solid wood can, but its lifespan is 20–30+ years with minimal maintenance.
Q: How do you cut and finish PU mouldings?
A: Cut PU mouldings with a fine-tooth miter saw (40+ teeth for a 10-inch blade) to avoid chipping the molded edge. Sand the cut edge with 220-grit, then apply two coats of interior latex paint. Mitre joints at corners, fill seams with lightweight spackle, sand smooth, and finish with one final top coat.
Q: Is PU moulding safe for indoor air quality?
A: Yes. Premium PU mouldings are manufactured without formaldehyde, asbestos, or VOCs. They meet EN 13501-1 Class E fire classification as a minimum, with Class B fire-retardant versions available for commercial projects. The factory-applied water-based primer further reduces off-gassing once installed.