MIXED MEDIA Dilemma

The original plaster walls in the living room in our 1908 Foursquare had been covered with a thin layer of drywall. Poorly installed to begin with, the drywall was held in place by a handful of drywall screws. As we broke it out, we exposed layers of wallpaper and paint over the original plaster scratch coat, which was in good shape. No finish coat had ever been applied.

After a long and messy wallpaper removal and patching process, we were left with a very irregular surface of about 80 percent plaster and 20 percent drywall. We decided on this approach: 1) a base coat embedded with fiberglass mesh over existing rough plaster and patched drywall; 2) a second coat to cover the mesh and produce a flat surface; and 3) finally a finish coat for a smooth and paint-ready surface. We’d arranged to use products from Master of Plaster, but at their recommendation used Structo-Lite, a modern mix-type base-coat plaster, as our base coat. Unlike traditional plasters, Structo-Lite is gypsum based so it won’t breathe the way a lime-based plaster breathes. (If we’d been in a house where maintaining the original plaster was important, we’d have used an all-lime plaster.)

After applying that base coat, we hung fiberglass mesh to bridge any cracks and gaps. Master of Plaster’s limebased wet-finish plastering product (the second coat) took some getting used to. We learned to use more plaster in thicker coats and a very low trowel angle to apply it.

Working from the top of the wall down, we applied a finish coat in sections of about 4' x 4' and immediately circled back with a spray bottle to spritz it and smooth out imperfections. Loading less material on the trowel, applying it, then immediately reloading the trowel proved most effective. Where the wall meets the ceiling, we applied a little bit of material in an upwards motion, followed by quickly inverting the trowel and applying it to the wall from the top down.

As the partially cured plaster is worked, it slowly transforms into an almost perfectly smooth surface with a little bit of coarse tooth to it. It may be left as a slightly rough finish, or a finish coat may be applied. We were thrilled that our finish coat required no sanding at all. Continued troweling and spraying refined the surface so much that it shines—just like real, historic plaster.

FAR LEFT Alex Santantonio applies the finish coat to newly refreshed plaster walls. The process results in a silkysmooth, almost shiny, paint-ready finish. Plaster “cream”— the wet and smooth byproduct of working the plaster after spritzing with water—is great for filling in the little gaps and voids left from the first pass.

LEFT Stripped of wallpaper and patched or secured with washers, the walls were ready for the plaster base coat.