Run a strip of painter's tape down the center of the toe rail in preparation for marking required measurements. Pencil marks can be difficult to see on dark stained surfaces, but the tape makes them more visible.
Determine the desired spacing for the balusters. Building codes typically stipulate a maximum spacing for balusters. Cut a block the length of the desired spacing and use it as a guide to mark the baluster positions along the painter's tape for both railing sections.
Set a pair of balusters upside-down on the tape in the positions just marked. Measure the widest gap between them. To ensure maximum child safety, no gap should be greater than 4 inches.
