How to Install Wallpaper on Plaster Walls in Denver

Plaster walls are common in Denver’s pre-1950 homes — and they’re actually wonderful for wallpaper when properly prepared. The key word is “prepared.” Skip the prep steps and plaster will fight every part of your installation. Do it right and plaster walls hold wallpaper better than drywall ever could.

Plaster Wall Estimate — (720) 719-8899

Identifying Plaster vs. Drywall

Tap your wall. Plaster sounds solid and dense — a dull thud. Drywall sounds hollow. Plaster walls are also noticeably harder to the touch and feel denser when you press against the surface. Check the thickness at an outlet or switch plate — plaster walls are typically ¾ to 1 inch thick, while drywall is ½ inch. Many Denver homes have a mix: original plaster in older sections and drywall in renovated areas or additions.

Horsehair plaster — common in Denver homes built before the 1930s — contains animal hair fibers mixed into the plaster for structural reinforcement. It’s denser, stronger, and more resistant to cracking than later lime plaster. It’s also more difficult to drill and cut, which matters when doing any wall prep work before installation.

  • Tap test: plaster sounds solid, drywall sounds hollow
  • Outlet plates: plaster walls are ¾–1” thick vs ½” drywall
  • Surface hardness: fingernail leaves no mark on cured plaster
  • Pre-1930s Denver homes: likely horsehair plaster construction

Hairline Cracks — Repair Before You Install

Hairline cracks in plaster are extremely common and not necessarily a structural concern. But they must be addressed before wallpaper installation. Cracks telegraph through thin paper wallcoverings — especially in raking light — and can widen over time as the plaster continues its slow movement, eventually cracking the wallpaper on top.

Hairline cracks (less than 1mm wide) can be filled with flexible joint compound or plaster repair compound, allowed to fully cure, sanded smooth, and then primed. Wider cracks (1–3mm) should be widened slightly with a utility knife to create a V-groove, filled with elastomeric patching compound, and then skim coated flush. Any crack wider than 3mm warrants a structural assessment before proceeding.

Common DIY Mistakes on Plaster

  • Papering over unfilled cracks — they show through immediately in raking light
  • Using standard drywall joint compound on old plaster — wrong flexibility, cracks again
  • Skipping primer — paste is absorbed instantly, creating a weak bond
  • Using too much moisture on old plaster — can reactivate old wallpaper adhesive layers beneath the surface
  • Not testing wall adhesion in a small area before proceeding with full installation

Proper Primer for Plaster Walls

Primer selection is critical on plaster. Old plaster is highly alkaline and very porous — the wrong primer either gets absorbed before it seals the surface or reacts with the alkalinity and fails to bond. For well-preserved plaster in good condition, an oil-based primer provides the best seal and bonds strongly to the alkaline surface. It takes 24 hours to cure but creates an excellent substrate for paste adhesion. For plaster with moderate porosity, a PVA-based wallpaper sizing primer applied in two coats is a strong alternative.

Why Plaster Holds Wallpaper Beautifully

Here’s the good news: properly prepped plaster walls hold wallpaper exceptionally well — better than most drywall. Plaster’s hard, dense surface doesn’t flex or give like drywall paper facing can. There’s no risk of the drywall face paper peeling away when wallpaper is eventually removed. And old plaster, being thicker and more thermally stable, doesn’t experience the minor flexing that causes drywall seams to telegraph through fresh wallpaper.

In Denver’s historic homes, we’ve done installations on plaster walls that are still holding beautifully 10+ years later. The prep takes more time — but the results are worth it. Plaster walls, done right, are some of the best surfaces a wallpaper installer can work on.

Hundreds of Plaster Wall Installs in Denver

We’ve installed wallpaper on plaster walls throughout Denver’s historic neighborhoods — Capitol Hill, Washington Park, Congress Park, Highlands, Curtis Park, and more. Every plaster wall install starts with a thorough assessment: we check crack severity, test wall adhesion, identify any hidden wallpaper layers, and select the right primer before a single panel goes up. No guessing, no shortcuts.

Free Plaster Wall Estimate — (720) 719-8899
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