What’s the best way to soundproof a room?

Short answer

For meaningful soundproofing, seal all gaps, upgrade doors and windows, and add mass plus decoupling to walls and ceilings. The most effective DIY path is: weatherstrip the door, install a door sweep, seal penetrations with acoustic caulk, fill stud cavities with mineral wool, add two layers of 5/8" drywall with Green Glue in between, and mount the drywall on isolation clips and hat channel to decouple it. Treat floors with dense underlayment or carpet over pad, and address vents and outlets to stop sound leaks.

How soundproofing works

To block sound, combine these four principles:
- Seal: Air gaps leak sound. Caulk and weatherstrip everything.
- Mass: Heavier surfaces block more sound (5/8" drywall, MLV, laminated glass).
- Decouple: Break direct connections so vibrations don’t pass through (clips + hat channel, staggered studs).
- Damp: Convert vibration to heat (Green Glue Compound between drywall layers).

Typical performance

Basic interior wall (single 1/2" drywall each side, empty): STC ~34
Add mineral wool + double 5/8" drywall + Green Glue: STC ~50–55
Add clips + hat channel + double 5/8" + Green Glue: STC ~55–60+

Step-by-step: prioritize by impact and budget

1) Quick fixes (1–3 hours, $50–$300)

• Doors: Install weatherstripping on jambs and a door sweep at the threshold. Upgrade to a solid-core door if you have hollow-core.
• Gaps & cracks: Seal baseboard-to-floor gaps, wall-to-ceiling seams, and trim perimeters with acoustic sealant (stays flexible). Use backer rod for large gaps.
• Outlets and switches: Apply acoustic putty pads around boxes; install foam gaskets behind cover plates.
• Vents: Line return-air grilles with acoustic foam and build a simple baffle box if airflow allows. Don’t block required ventilation.

2) Windows (2–6 hours, $150–$1,000+)

• Add weatherstripping and acoustic caulk around the frame.
• Install laminated glass storm inserts or an acoustic interior window insert. DIY window plugs (MDF + foam gasket) work for occasional use.

3) Walls: mid- to high-impact (weekend+, $300–$2,500 per wall)

• Remove trim, locate studs with a stud finder. Fill cavities with mineral wool (Roxul Safe’n’Sound).
• For best results, mount isolation clips and hat channel across studs. Then install two layers of 5/8" Type X drywall with Green Glue between layers. Perimeter and seams get acoustic sealant.
• Alternate budget path: Add mass loaded vinyl (MLV, 1 lb/ft²) behind one layer of 5/8" drywall, then Green Glue + second layer.

4) Ceilings and floors (timeline varies, $400–$4,000+)

• Ceilings (below noisy area): Similar to walls—clips + hat channel, two layers 5/8" drywall, Green Glue. Use IC-rated recessed light backer boxes or avoid can lights.
• Floors: If you control the floor above, install acoustic underlayment (rubber or cork), then new flooring. Carpet with a dense pad helps. For subfloor work, use damping compound between plywood layers.

Tools and materials

• Tools: drill/driver, screw gun, drywall lift or helper, utility knife, oscillating multi-tool, caulk gun, taping knives, stud finder, level, shears for MLV, PPE.
• Materials: acoustic sealant, backer rod, weatherstripping, door sweep, solid-core door, mineral wool batts, isolation clips + hat channel, 5/8" Type X drywall, Green Glue Compound + sealant, MLV, putty pads, acoustic gaskets, acoustic underlayment.

Safety and code considerations

• Weight: Two layers of 5/8" drywall are heavy. Lift with help or a drywall lift. Plan fastener spacing per manufacturer.
• Dust and fibers: Wear eye protection, gloves, and a respirator when cutting drywall or handling mineral wool.
• Electrical: Maintain box fill limits and clearance. Use listed putty pads; don’t pack insulation inside boxes.
• Fire and egress: Preserve fire-rated assemblies and emergency exits. Use Type X drywall where required.
• HVAC: Don’t obstruct supply/return airflow. Large duct changes may require an HVAC pro and permits.

Tips for best results

• Seal first, then build: Any pinhole is a leak path. Run a continuous bead of acoustic sealant around the entire perimeter of new layers.
• Stagger seams: Offset drywall seams between layers to avoid weak lines.
• Avoid short-circuiting: With resilient channel, don’t drive screws into studs by mistake—use a depth stop and mark channel lines.
• Break flanking paths: Avoid back-to-back outlets on opposite sides of the same stud bay. Relocate or stagger if possible.
• Choose the door wisely: A solid-core door with perimeter seals and an automatic drop seal can deliver a big improvement fast.

Common mistakes

• Using thin foam “egg-crate” panels hoping to block noise. Those absorb echoes inside the room but barely block transmission.
• Skipping sealing of edges and penetrations. A 1% open gap can negate major upgrades.
• Rigidly tying new drywall to studs after installing clips/channel. That defeats decoupling.
• Overloading a hollow-core door with heavy MLV without upgrading hinges/structure.
• Forgetting the ceiling—impact noise often travels through joists.

Rough costs and time

• Quick sealing + door sweep/weatherstripping: $50–$150, 1–2 hours.
• Solid-core door + seals: $250–$600, 2–4 hours.
• One wall: mineral wool + clips/channel + two 5/8" layers + Green Glue: $800–$1,800 in materials, 1–2 days DIY.
• Ceiling treatment: $1,200–$3,000+ depending on area and fixtures.

When to call a pro

• You need verified STC/IIC performance for a studio or rental unit.
• Structural changes, large ceiling spans, or heavy assemblies over occupied spaces.
• Electrical relocation, recessed lighting backer boxes, or major HVAC rerouting.
• Condo/HOA fire-rated assemblies that must maintain certification.

Example upgrade path

1) Seal doors, outlets, and trim. 2) Replace door with solid-core and add perimeter seals. 3) Treat the noisiest shared wall with clips + channel, mineral wool, double 5/8" drywall with Green Glue. 4) Address ceiling or windows as needed. This staged approach delivers measurable improvements at each step while controlling cost and complexity.