Why Insulate Plaster Walls?
Main Benefit: Energy Efficiency
- Older homes with plaster walls tend to be drafty, leading to higher heating and cooling bills.
- Insulation helps regulate indoor temperatures, keeping your home warmer in winter and cooler in summer.
- Potential Savings: Homeowners save an average of 15% (or $200–$600 per year) on utility bills with proper insulation.
Challenges of Insulating Plaster Walls
- Moisture Risks: Poorly installed insulation can trap moisture, causing mold and wood rot.
- Structural Integrity: Drilling or retrofitting can damage the lath and plaster if not done correctly.
- Repair Needs: Cracks in plaster may need repair before and after insulation to prevent further damage.
How Professionals Insulate Plaster Walls
- Inspection & Prep: Identify cracks, repair damage, and ensure structural stability.
- Blown-in or Spray Foam Insulation:
- Loose Fill or Foam: Injected through small holes in the walls.
- Sealed with a vapor-resistant primer and water barrier to prevent moisture buildup.
- Optional Additions:
- Cladding: Extra insulation layer between the outer wall and insulation.
- Rainscreen Layer: Ensures water doesn’t penetrate walls.
- Final Touch: Repaint walls with vapor-resistant paint for added protection.
Costs of Insulating Plaster Walls
- Labor & Materials: $1–$4 per square foot.
- Spray Foam Insulation: $0.45–$1.50 per board foot.
- Blown-in Cellulose: $0.60–$2.30 per square foot.
- Plaster Repairs: $200–$1,200, depending on damage.
- Home Energy Audit: $100–$1,650 (Average: $407).
DIY vs. Professional Installation
DIY Challenges:
- Improper insulation can lead to moisture problems and structural damage.
- Requires expertise to ensure proper sealing and vapor barriers.
Why Hire a Pro:
- Ensures the integrity of plaster walls and prevents future damage.
- Includes proper sealing, moisture resistance, and professional repairs.
Summing it up
- Insulating plaster walls is an effective way to save energy and reduce utility costs.
- Proper installation by a professional is critical to avoid mold, rot, and structural damage.
- Pair insulation with a home energy audit to maximize efficiency and identify other areas for improvement.
- The return on investment (ROI) is high, with long-term energy savings and increased home value.
If you're dealing with drafty plaster walls, adding insulation is a wise choice—but leave it to the experts for best results!
Next: Read 2500+ consumer guides to shopping, electronics, appliances, home services, cars, money and more.
