Soundproofing a Door – Tips for Quieter Rooms

Why Doors Are Acoustic Weak Points

While you might invest heavily in soundproofing walls, ceilings, and floors, doors often remain the primary path for noise transmission. Here's why:

• Gaps and Air Leaks: Most doors have visible gaps around the frame and under the bottom edge. Sound travels through air, so any air gap is also a sound leak.
• Lightweight Construction: Standard hollow-core doors are essentially cardboard honeycomb structures with thin veneer faces—they provide almost no sound blocking.
• Poor Sealing: Unlike windows with compression seals, most doors rely on simple stops that leave significant air gaps when closed.
• Hard Surfaces: Door surfaces reflect sound rather than absorbing it, contributing to echo and reverberation in the room.

The good news? Door soundproofing is one of the most cost-effective acoustic improvements you can make, with noticeable results from even basic treatments.

Step 1: Seal All Gaps & Air Leaks

The single most important step in door soundproofing is eliminating air gaps. Remember: if air can pass through, so can sound. Even a 5mm gap under a door can reduce your wall's acoustic performance by 50% or more.

Seal the Door Perimeter

Apply acoustic weather stripping around the entire door frame—top, sides, and hinge side. Unlike standard weather stripping designed for thermal insulation, acoustic-grade seals provide consistent compression and maintain their effectiveness over thousands of open/close cycles.

Installation Tips:

• Clean the door frame thoroughly before application
• Measure carefully—you want compression when the door closes, but not so much that it's difficult to close
• Use self-adhesive foam or rubber seals for easy DIY installation
• Pay special attention to corners where gaps are often largest

Install a Door Sweep or Drop Seal

The gap under the door is typically the largest acoustic leak. Two solutions:

Door Sweep: A simple brush or rubber blade that attaches to the bottom of the door and drags along the floor. Inexpensive and easy to install, but can wear carpets and may not provide complete sealing.

Automatic Drop Seal (Recommended): A spring-loaded mechanism that automatically lowers a seal when the door closes and retracts when opened. Provides superior acoustic sealing without dragging on the floor. More expensive but far more effective for serious soundproofing.

Seal Gaps with Acoustic Sealant

For permanent installations, use high-performance acoustic sealant to fill any gaps between the door frame and wall structure. Unlike standard decorator's caulk, acoustic sealant remains permanently flexible and won't crack or shrink over time.

Application:

• Apply around the door frame where it meets the wall
• Fill any visible gaps or cracks in the door frame itself
• Use a professional sealant gun for consistent application
• Smooth with a wet finger or tool before it skins over
• Allow 24-48 hours to cure fully

Expected Improvement: Sealing gaps alone can improve door soundproofing by 10-15 dB, making noise roughly half as loud. This is the highest ROI step in door soundproofing.

Step 2: Add Mass to Block Sound

Once gaps are sealed, the next priority is adding mass to the door itself. Sound transmission follows the mass law—doubling the mass of a barrier improves soundproofing by approximately 6 dB.

Mass Loaded Vinyl (MLV) - Professional Solution

Mass loaded vinyl (MLV) is a dense, flexible material specifically engineered for soundproofing. At 5-10 kg/m², MLV adds significant mass without excessive thickness.

Installation Methods:

Option 1: Attach Directly to Door

• Measure your door and cut MLV to size (leave 25mm clearance around edges)
• Use self-adhesive acoustic membrane or construction adhesive
• Apply to the side of the door facing the noise source
• Cover with decorative fabric or thin plywood for aesthetics

Option 2: Create a Removable Barrier (Ideal for Rentals)

• Build a lightweight frame from 25mm x 50mm timber
• Stretch MLV across the frame and staple edges
• Cover with fabric for a professional finish
• Hang on hooks or lean against the door when needed
• Remove when you move out—no permanent modifications

Product Recommendations:

• SilentCloud 10 kg MLV (1.2m x 2.0m) - Premium performance for maximum noise blocking
• 5kg Barrier Mat (1.2m x 2.0m) - Cost-effective option for moderate noise issues
• 4mm Self-Adhesive Acoustic Barrier (7 kg/m²) - Easy installation with adhesive backing

Acoustic Blankets - Budget-Friendly Alternative

If MLV is outside your budget, heavy moving blankets or purpose-made acoustic blankets can provide moderate improvement:

• Hang from a curtain rod or hooks above the door
• Ensure the blanket extends beyond the door frame on all sides
• Use multiple layers for better performance
• Completely removable and reusable

Performance Note: Acoustic blankets typically improve soundproofing by 5-8 dB, compared to 10-15 dB for MLV. They're best for temporary solutions or rental properties where permanent modifications aren't allowed.

Acoustic Panels - Dual Purpose

For doors in home studios, practice rooms, or home cinemas, consider attaching acoustic absorption panels to the door surface:

• Reduces echo and reverberation within the room
• Provides modest soundproofing improvement (3-5 dB)
• Improves room acoustics for recording or critical listening
• Can be combined with MLV for maximum effect

Expected Improvement: Adding mass with MLV can improve door soundproofing by 10-15 dB, making a significant difference in perceived noise levels.

Step 3: Upgrade to Solid-Core Door

If you're serious about soundproofing and have the budget, replacing a hollow-core door with a solid-core door is the single most effective upgrade.

Door Types Compared

Installation Considerations

Check Hinge Capacity: Solid-core doors are 3-4x heavier than hollow-core doors. You may need to upgrade to heavy-duty hinges (typically 3 hinges for doors over 35kg).

Frame Strength: Ensure your door frame is properly secured to the wall structure. Loose frames will vibrate and reduce soundproofing performance.

Professional Installation: Solid-core doors require precise hanging to ensure proper operation and seal compression. Consider professional installation if you're not experienced with door hanging.

Cost vs Performance: A solid-core door costs £100-300 compared to £30-60 for hollow-core, but provides 10-15 dB better soundproofing—roughly 3-4x quieter. For bedrooms, home offices, or studios, this is money well spent.

Step 4: Additional Acoustic Treatments

Heavy Curtains or Portières

Install a heavy curtain or portière (door curtain) on the noisy side of the door:

• Creates an air gap between curtain and door (improves isolation)
• Absorbs sound that would otherwise reflect off the door
• Adds modest mass (3-5 dB improvement)
• Provides visual privacy and draft reduction
• Completely reversible—ideal for rentals

Installation: Mount a curtain rod 150-200mm above the door frame and extend 100mm beyond each side. Use heavyweight fabric (velvet, wool, or multi-layer thermal curtains work well).

Door Gaskets and Compression Seals

For maximum performance, install compression gaskets around the entire door frame:

• Silicone or neoprene gaskets compress when the door closes
• Creates an airtight seal similar to a refrigerator door
• Requires precise installation and door adjustment
• Can improve soundproofing by an additional 5-8 dB when combined with other treatments

Acoustic Mineral Wool in Hollow Doors

If replacing your hollow-core door isn't an option, you can improve its performance by filling the cavity:

Method:

1. Drill 25mm holes along the top edge of the door (space every 150mm)
2. Use acoustic mineral wool torn into small pieces
3. Feed mineral wool into the cavity through the holes
4. Fill completely but don't over-compress (reduces effectiveness)
5. Seal holes with wood filler and repaint

Performance: This adds mass and damping, improving soundproofing by 5-8 dB. Combined with sealing and MLV, even a hollow-core door can achieve moderate soundproofing.

Caution: This is a permanent modification and may void warranties. Only suitable for doors you own.

Key Takeaways & Product Recommendations

Recommended Products for Door Soundproofing

Performance Expectations by Budget

Common Mistakes to Avoid

• Ignoring Gaps: Adding mass without sealing gaps wastes money. Always seal first.
• Using Standard Caulk: Decorator's caulk cracks and shrinks. Use proper acoustic sealant.
• Over-Tightening Screws: When attaching MLV or panels, don't over-tighten—this creates rigid connections that transmit vibration.
• Expecting Miracles from Foam: Acoustic foam absorbs echo but doesn't block sound transmission. Use mass-based products for soundproofing.
• Forgetting the Frame: A soundproof door in a loose, rattling frame won't perform well. Ensure the frame is solid and properly sealed to the wall.

Related Soundproofing Guides

• Soundproofing a Wall – Complete Guide
• Soundproofing a Ceiling – Reduce Noise from Above
• Soundproofing a Floor – Guide to Reducing Impact & Airborne Noise
• Technical Guides to Soundproofing – Understanding Acoustic Science
• 5kg vs 10kg MLV: Which Soundproofing Mat Do You Need?