Paint-grade wainscot on a curved stairwell
With the use of bendable materials and flexible molding, builder Joe Milicia took the challenge of working with wainscot to a new level
Working on a paint-grade trim job gives a finish carpenter the latitude to use disparate materials that blend together under the paint. The physical characteristics are what determines the choice of materials. For instance, plywood trumps solid stock when it comes to stability, a smooth surface is better than open grain, and laminations usually are preferred for bending.
On this job, one of our tasks was to run a raised-panel wainscot along the wall of a spiral staircase. Because the trim extended up to and past eye level, the layout had to be right on the money, and the finish had to be pristine. We needed materials that were flexible enough to bend easily to the curve of the wall but that wouldn’t require days of finish prep.
We took over the stairwell before the stairs were measured and the drywallers had arrived. Rather than spend a day setting up staging and ladders in the twostory stairwell, I drew the layout on the bench, so to speak. Of course, it’s almost impossible to use a tape measure on a curved wall, so we ripped 3-in.-wide strips of bending lauan and tacked them end to end along the wainscot’s planned top-rail position to make a story pole. Once the length of the layout was established, we took down the strips and divided the total length by a suitable number of stiles and panels, then transferred these measurements back to the flexible story pole. After covering the walls with two layers of bending lauan, we nailed the story pole back in place. The stile locations were plumbed down from the top rail, and we penciled the remaining layout on the wall.
Three carpenters spent nine days in the shop and at the site to finish the installation. The completed staircase is the jewel of the home’s entry.
Curved assembly is a union of disparate materials
The beauty of paint-grade trim is that only the surface that receives the paint has to be uniform; the substrate is chosen for its best characteristic, whether it is flexible enough to conform to curved walls or a material that remains stable throughout the seasons. On this stair, bending plywood formed the substrate of the backing, stiles, and rails. The raised panels consisted of a hardboard and kerfedparticleboard panel picture-framed with MDF and a flexible molding.
Trick of the trade
Faced with curved work, I like to use ready-made bending plywood, often known by trade names such as Wacky Wood or Wiggle Wood. Lauan, birch, or Italian-poplar veneers are laid up so that the grain orientation allows the sheet to bend along one dimension rather than add strength. Available in 3/8-in., 1/4-in., and 1/8-in. (poplar) thicknesses, the plywood comes in 4×8 or 8×4 sheets; that is, it bends along the length of the sheet or along the width. According to wholesaler North American Plywood Corp., a 3/8-in.-thick sheet can bend to a radius of 7 in. and costs about $40; Italian poplar costs about $25 per sheet. Check your local plywood distributor for availability.
Photos by Charles Bickford, except where noted