Remove your carpet before replacing your baseboards, so your baseboards have a solid foundation. If you try to install baseboards over your carpet, there is a strong likelihood that your baseboards will float on top of your carpet. As your carpet gives and stretches, you will see gaps and spaces between your carpet and baseboards. Your baseboards may even warp and bend out of place.
If you install baseboards too tightly over your carpet, the underlying tackstrip could damage your carpet, causing it to rip or fray. The tackstrip is a narrow piece of wood, lined with tiny tacks or nails that hold a carpet in place to keep it from slipping or sliding. Jack King, owner of Arizona Home Floors, states that baseboards should be installed before new carpet is installed because baseboards push the carpet down on the tackstrip.
Peel back or remove your carpet before replacing your baseboards to make future carpet removal or replacement easier. If you install baseboards over your carpet, you will have to remove them again when you eventually replace your carpet. Otherwise, you risk damaging your baseboards by pulling and yanking on your carpet to dislodge it from the tackstrips.
Failure to remove carpeting before replacing baseboards can compromise the structure of the baseboards. Since baseboards are long and thin, they cannot sustain much torque or vertical force. When you need to remove your carpet in the future, the pressure of baseboards installed on top of the carpet can cause them to break or splinter when you try to remove carpeting beneath them.