Wallpaper or paint on old horsehair plaster walls

What horsehair plaster walls look like after a hundred years in a Quincy house

Most Quincy houses built before about 1940 have plaster on wood lath: the two-families and triple-deckers in Wollaston and North Quincy, the Victorians and Foursquares on Wollaston Hill, and the older Colonials in Milton and Dedham. The scratch coat was pushed through the gaps in the lath, a brown coat built thickness, and a thin, hard finish coat went on last. Horsehair or other animal hair was mixed into the base coats to hold them together. Done well, it is a dense, quiet, durable wall that drywall can't match.

After a century, though, the surface tells its history. Houses settle, so you see diagonal cracks off door and window corners. Keys behind the lath break, and sections bulge slightly. Previous owners patched holes with joint compound, spackle or a scrap of drywall, and each patch has a slightly different texture. Old wallpaper may have been removed, leaving glue residue and scraped spots. All of this affects which finish will look good.

When paint is the right choice on old plaster

Paint is a fine choice when the plaster is firmly attached, with only minor cracks and a gentle wave you can live with. Many owners like that wave; it's part of an old house. The key is sheen. Flat and matte finishes scatter light and hide unevenness, while eggshell and satin highlight every ripple, especially under a ceiling fixture or raking window light.

Before painting, cracks need to be opened, filled with a setting-type compound and, for any crack that has moved, bridged with mesh or paper tape. Loose plaster needs re-attaching with plaster washers or adhesive before any patching. Then the whole wall gets primed, so patches and old surfaces take the finish evenly. Without primer, patches flash through the paint as dull or shiny spots.

• Plaster firmly attached to the lath, with no soft or hollow areas
• Cracks that are hairline or have been stable for years
• Only a few patches, each feathered flat
• A flat or matte finish on walls, saving satin for trim

When wallpaper hides plaster flaws better than paint

Wallpaper wins on walls where paint would only highlight the problems. A busy pattern, a textured paper, a grasscloth or a heavy embossed paper draws the eye away from small waves, and its body covers hairline cracks that would show through a coat of paint. Rooms where a lot of patching has been done, such as kitchens that had cabinets moved or bedrooms with old outlet changes, often look far better papered.

Wallpaper still needs a sound wall. It will not hold loose plaster in place, and a crack that moves will split the paper eventually. Heavy prints with large flat areas of color behave more like paint, because they show every bump. Thin, smooth papers with shiny inks can be less forgiving than a flat paint. The best plaster-hiding papers are textured, matte and patterned.

Pattern scale matters too. A small, all-over print with no obvious vertical lines forgives walls that are out of plumb, which almost every old Quincy room is, especially on the upper floors of a triple-decker that has settled for a century. Stripes and large geometric repeats do the opposite: a corner that leans half an inch over eight feet makes a stripe look crooked against the trim. On wavy walls, we often steer clients toward florals, damasks, small geometrics and textured papers instead.

When a skim coat should come before paint or wallpaper

A skim coat is a thin layer of joint compound or veneer plaster spread across the entire wall and smoothed flat. It makes sense when a wall has many cracks, a lot of patching, glue residue from old paper, or a rough, pitted surface. Skimming turns a patchwork wall into a single uniform surface, so both paint and wallpaper read clean.

Skim coating adds time. A typical room takes two to three coats with drying between, then sanding and priming, so plan on two to four days for the walls of an average bedroom. Drying runs slower in a humid August near the bay and faster in a heated house in winter. In pre-1978 houses we treat the old surface as having lead paint, so any sanding of the original wall happens with dust control and the skim coat goes over the old finish rather than grinding it off. It costs more than paint alone, but on a rough wall it is the difference between a good finish and an obvious one.

How liner paper helps on cracked or patched plaster

Liner paper is a plain, unprinted paper hung on the wall before the finish. It is often hung horizontally so its seams never line up with the seams of the decorative paper above. Liner bridges hairline cracks, evens out small texture changes between patches, and gives wallpaper a consistent surface to grip, which helps it shrink and dry evenly.

Liner can also be painted. On a plaster wall with stable crack patterns and too many patches for paint alone, a heavy-weight liner hung, sealed and painted flat gives a smooth wall without a full skim coat. It does not fix loose plaster, a deep bow, or moving cracks. Those need repair first.

• Hang liner horizontally when wallpaper will follow
• Use a heavier grade on more uneven walls
• Prime and size the wall before liner goes up
• Repair loose plaster before any liner or paper

How to decide room by room in an older Quincy or Norfolk County house

We usually recommend different answers for different rooms. A front parlor on Wollaston Hill with tall ceilings, good plaster and original trim often looks best in a flat paint, maybe with a period paper on one wall. A kitchen or back hall in a two-family with decades of patches might be a candidate for a skim coat or a textured paper. A bedroom with old glue residue might need liner first.

The way to decide is to look at each wall with a work light held flat against it. That raking light shows every ripple, crack and patch. At our walk-throughs across Quincy and Norfolk County we do exactly that and talk through which finish each room can carry. Call (617) 576-8235 to set one up, and we'll explain what each option would mean for your walls.