Drywall vs Plaster: Remodeling Older Philadelphia Homes

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If you own a home in Philadelphia — especially in neighborhoods like Society Hill, Germantown, Chestnut Hill, or along the Main Line — there's a good chance your walls are plaster, not drywall. Homes built before the 1950s almost universally used plaster and lath construction, and the greater Philadelphia area has one of the highest concentrations of pre-war housing stock in the country. When it comes time to renovate, one of the first decisions you'll face is whether to repair the existing plaster or replace it with modern drywall.

It's not always a straightforward choice. Both materials have real advantages, and the right answer depends on your home's condition, your renovation goals, and your budget. Here's what you need to know.

Understanding What's Behind Your Walls

Traditional plaster walls consist of three layers applied over thin wooden strips called lath. A "scratch coat" is pressed through the lath gaps, forming small anchors called keys. A "brown coat" builds up thickness, and a smooth finish coat completes the surface. The result is a dense, hard wall that can be 3/4 inch to over an inch thick.

Drywall (also called sheetrock or gypsum board) is a factory-made panel — typically 1/2 inch thick — that gets screwed to wall studs and finished with tape and joint compound. It became the standard for residential construction starting in the 1950s because it's faster and less expensive to install.

The Case for Keeping Plaster

Philadelphia homeowners often underestimate how much plaster contributes to their home's character and performance. Here's what plaster does well:

• Superior soundproofing. Plaster walls are significantly denser than drywall, which means better sound isolation between rooms. In row homes — where you share walls with neighbors — this matters.
• Better fire resistance. The thickness and density of plaster provides more fire resistance than standard 1/2-inch drywall.
• Harder, more durable surface. Plaster resists dents, dings, and punctures far better than drywall. It holds up to decades of daily life.
• Historic character. Plaster walls often have subtle texture and slight imperfections that give older homes warmth. Perfectly flat drywall can look out of place in a 1920s colonial.
• Potential historic value. If your home is in a Philadelphia historic district or you're pursuing historic tax credits, preserving original plaster may be required or beneficial.

The Case for Switching to Drywall

There are legitimate reasons to remove plaster and install drywall during a renovation:

• Extensive damage. When plaster has separated from the lath over large areas (you'll hear a hollow sound when you knock), patching becomes impractical. If more than 40–50% of a wall's plaster has failed, replacement is often more cost-effective.
• Electrical and plumbing upgrades. Older Philadelphia homes frequently need rewiring (knob-and-tube replacement) or plumbing updates. Running new wires and pipes through plaster and lath is difficult and destructive. Opening the walls for mechanical upgrades and closing with drywall is often the most practical approach.
• Insulation improvements. Many pre-war Philadelphia homes have little to no wall insulation. If you're opening walls anyway, it's the perfect opportunity to add insulation — and drywall makes it easier to close up cleanly.
• Cost savings. Skilled plaster repair runs $3–$8 per square foot for patch work. Full plaster restoration can reach $10–$15+ per square foot. New drywall installation typically costs $2–$4 per square foot, including finishing.
• Easier future repairs. Drywall patches are straightforward for any contractor. Plaster repair requires specialized skills that are increasingly hard to find.

The Hybrid Approach: What We Recommend Most Often

In our experience working on hundreds of older homes across Philadelphia and the Main Line, the best approach is usually a room-by-room decision rather than an all-or-nothing choice. Here's our typical recommendation:

• Keep plaster in rooms where it's in good condition and you're not doing mechanical (plumbing/electrical) work. Patch cracks and repaint.
• Switch to drywall in rooms where you're opening walls for plumbing, electrical, or HVAC upgrades — especially kitchens and bathrooms.
• Skim-coat over plaster when the surface is rough or has minor damage but the plaster is still firmly attached to the lath. This preserves the wall's mass and soundproofing while giving you a smooth, paintable finish.
• Install drywall over plaster in some cases where the plaster is intact but cosmetically damaged. This adds cost in terms of trim adjustments (door casings, window sills, outlet boxes need extending) but avoids the mess and expense of demolition.

What to Consider Before You Decide

Before committing to a path, think through these factors:

1. Scope of your renovation. A cosmetic refresh (paint, fixtures) argues for keeping plaster. A gut renovation with mechanical upgrades argues for drywall.
2. Your home's age and district. Philadelphia's Historical Commission has jurisdiction in designated historic districts. Check whether your project needs approval.
3. Noise concerns. If you're in a twin or row home, think twice before removing plaster from shared walls. The sound reduction difference is real.
4. Disposal costs. Plaster demolition generates heavy debris. In Philadelphia, disposal costs for plaster can add $500–$1,500+ to a project depending on the amount removed.
5. Timeline. Plaster repair and skim coating requires multiple coats with drying time between each. If you're on a tight schedule, drywall is faster.

Why This Decision Matters for Plumbing and HVAC Work

At GenServ Pro, we often encounter the drywall-vs-plaster decision during plumbing and HVAC projects. Running new supply lines, drain pipes, or HVAC ductwork through plaster and lath walls requires careful planning. The lath strips complicate routing, and plaster doesn't forgive sloppy patching the way drywall does.

When we're replumbing a bathroom in a 1930s Narberth colonial or installing a ductless mini-split in a Rittenhouse Square brownstone, we coordinate with our construction team to ensure the wall work is handled correctly — whether that means skilled plaster patching or clean drywall installation. Having plumbing, HVAC, and construction under one roof means fewer contractors, better coordination, and a finished product that looks right.

Getting Started With Your Renovation

If you're planning a renovation in an older Philadelphia-area home — whether it's a kitchen remodel, a bathroom upgrade, or a whole-house project — the wall question will come up. The best time to address it is during the planning phase, not after demolition has already started.

We recommend scheduling a walkthrough with a contractor who understands both plaster and drywall, and who can evaluate your walls' condition honestly. That assessment should include checking for plaster adhesion, identifying any moisture damage, noting where mechanical upgrades might be needed, and providing options with realistic cost estimates.