Posted by Wall Panels World on 10th Oct 2025
How To Soundproof A Room
Soundproofing reduces noise transmission between spaces by adding mass, absorbing sound energy, preventing vibrations, and eliminating sound paths. The approach depends on whether you're blocking airborne noise like voices and music, or impact noise like footsteps and door slams.
Note: Soundproofing requires structural work in most cases. Surface treatments like acoustic panels reduce echo and reverb within a room but don't block sound from passing through walls, floors, or ceilings.
Airborne vs Impact Sound
Sound travels through buildings in two distinct ways, and effective soundproofing addresses both types differently.
Most soundproofing situations involve both types. A flat above you creates impact noise through the floor structure and airborne noise from voices and music. The best approach uses techniques that address both simultaneously.
Four Soundproofing Principles
Effective soundproofing combines four distinct approaches. Using multiple principles together produces better results than relying on any single method.
1. Mass
Heavy, dense materials require more energy for sound to pass through. A single brick wall blocks more sound than a thin plasterboard partition because it has greater mass. Doubling the mass of a wall roughly halves the sound transmission.
Common materials:
- Multiple layers of plasterboard
- Mass loaded vinyl (thin rubber sheeting loaded with barium sulphate)
- Dense concrete or brick
- Acoustic plasterboard (typically 15kg/m² vs standard 10kg/m²)
2. Absorption
Porous materials trap sound energy within their structure, converting it to tiny amounts of heat through friction. This mainly affects sound within a cavity rather than blocking transmission through a wall, but fills the space where sound would otherwise resonate and amplify.
Common materials:
- Mineral wool insulation (acoustic grade 60-80kg/m³)
- Acoustic foam (primarily for treating room acoustics)
- Fibreglass insulation
- Rockwool slabs
3. Decoupling
Breaking the physical connection between surfaces prevents vibrations from travelling directly through the structure. If one side of a wall can vibrate without directly moving the other side, sound transmission drops significantly.
Common methods:
- Resilient bars (metal channels that hold plasterboard away from studs)
- Staggered stud walls (alternating which studs support each face)
- Floating floors (floor surface not directly attached to joists)
- Room-within-a-room construction
4. Damping
Viscoelastic materials convert vibration energy into heat, reducing the tendency of surfaces to resonate and transmit sound. Applied between rigid layers, damping compounds prevent panels from acting like drum skins.
Common materials:
- Green Glue (applied between layers of plasterboard)
- Acoustic mats (used under flooring)
- Constrained layer damping sheets
- Mass loaded vinyl with damping properties
Combining principles produces the best results. A wall using mass (multiple plasterboard layers), absorption (mineral wool in cavity), decoupling (resilient bars), and damping (Green Glue) will significantly outperform a wall using only one approach.
Soundproofing Walls
Walls present the largest surface area for sound transmission between rooms. The approach depends on whether you're working with a new build, can access the wall cavity, or need to work from one side only.
New Build or Full Access
High-performance stud wall construction:
Use 100mm or 150mm studs spaced at 600mm centres. Deeper cavities provide more space for absorption material and natural decoupling.
Fill cavity completely with 60kg/m³ or denser mineral wool. Avoid gaps which create acoustic bridges.
Install resilient bars horizontally across studs on at least one side. This decouples the plasterboard from direct stud contact.
Apply Green Glue or similar damping compound between two layers of plasterboard. Use approximately one tube per sheet.
Fix two layers of 12.5mm or 15mm plasterboard with staggered joints. Acoustic-grade plasterboard adds further mass.
Working From One Side Only
When you can't access the wall cavity - perhaps in a flat with neighbours - you build outward from your side of the existing wall.
Independent Stud Wall
Build a new stud wall 25-50mm away from the existing wall without any physical connection. Fill the gap and new cavity with mineral wool, then finish with two layers of plasterboard on resilient bars with Green Glue between layers.
Space loss: 125-175mm from the existing wall. Performance: Excellent if done properly.
Direct-Fix System
Fix acoustic hangers or resilient bars directly to the existing wall, add mineral wool between them, then install two layers of plasterboard with damping compound. Less effective than an independent wall but uses minimal space.
Space loss: 50-75mm from the existing wall. Performance: Moderate, some vibration still transfers through fixings.
Common mistake: Fixing resilient bars too tightly or adding too many fixing points. Each fixing point creates a path for vibration to bypass the resilient mount. Follow manufacturer specifications for fixing density.
Floors and Ceilings
Impact noise from floors above causes most complaints in flats and conversions. The floor above is someone else's ceiling below, so the most effective solutions involve both surfaces.
Soundproofing Floors (From Above)
Treating the floor where impact occurs provides the most effective reduction in footstep noise and vibration.
Soundproofing Ceilings (From Below)
When you can't treat the floor above, working from the ceiling below provides some improvement but won't match the performance of treating the impact source.
Suspended ceiling with resilient bars:
Fix resilient bars perpendicular to joists, maintaining the specified gap (typically 25mm) from the existing ceiling.
Add mineral wool between the joists (100-150mm depth) to fill the cavity and absorb sound.
Apply damping compound (Green Glue) to the first layer of plasterboard before fixing to resilient bars.
Install a second layer of plasterboard with staggered joints. Acoustic-grade board adds extra mass.
This approach reduces impact noise by 8-15dB. For comparison, treating the floor above with a floating floor system typically achieves 15-25dB reduction. The difference comes from stopping vibrations at their source rather than trying to catch them after they've entered the structure.
Doors and Windows
Doors and windows create the weakest points in room soundproofing. Gaps around frames allow sound to bypass even heavy walls, and thin glazing transmits far more sound than solid construction.
Doors
Internal doors typically offer minimal sound resistance. A standard hollow-core door might reduce sound by only 15dB, compared to 45dB+ for a properly soundproofed wall.
| Solution | Method | Reduction |
|---|---|---|
| Replace Door | Solid core door (44mm minimum thickness) provides more mass than hollow construction | ~10dB improvement |
| Seal Perimeter | Acoustic door seals (compression gaskets) around frame, automatic drop seal at bottom | ~8dB improvement |
| Add Mass | Fix mass loaded vinyl to existing door surface, covered with thin MDF facing if desired | ~6dB improvement |
| Acoustic Door | Purpose-built with seals, mass, and possibly air gap construction (expensive option) | ~30dB improvement |
Windows
Single glazing provides minimal sound insulation. Standard double glazing improves this, but the specific construction affects performance significantly.
Window construction factors:
- Glass thickness: Different thickness panes (e.g., 4mm + 6mm) perform better than equal thickness (4mm + 4mm) because they resonate at different frequencies
- Air gap: Wider gaps improve performance up to about 150mm, beyond which improvement plateaus. 100mm provides good performance. Gaps under 10mm offer minimal soundproofing benefit
- Acoustic laminate: PVB interlayer in laminated glass damps vibrations. Noticeably improves sound insulation, particularly for traffic noise
- Frame seals: Well-sealed frames matter as much as the glass. Poorly fitted units leak sound around edges
Affordable Options
- Heavy curtains with pelmet reduce high-frequency sound but have limited effect on traffic noise
- Magnetic or compression window inserts create a secondary glazing layer (50-100mm air gap gives good results)
- Seal any gaps around window frames with acoustic sealant
Higher Performance
- Acoustic double glazing (6mm + 100mm air gap + 10mm laminate) provides 40-45dB reduction
- Secondary glazing fitted 100-150mm inside existing window creates effective barrier without window replacement
- Triple glazing with acoustic specification (progressively thicker panes) achieves 45-50dB reduction
Standard thermal double glazing (designed for heat insulation) typically provides only 28-32dB sound reduction. Acoustic double glazing achieves 38-45dB. The cost difference is substantial, so specify acoustic performance clearly if sound reduction is the primary concern.
Realistic Soundproofing
Soundproofing reduces noise levels but rarely eliminates sound completely. The amount of reduction you can achieve depends on the starting point, the construction methods used, and how thoroughly you address weak points.
Decibel Scale Context
The scale is logarithmic, so a 10dB reduction cuts perceived loudness roughly in half.
| Reduction | Perceived Change | Typical Method |
|---|---|---|
| 3-5dB | Barely noticeable difference | Acoustic panels, soft furnishings (room acoustics only) |
| 8-10dB | Noticeably quieter, roughly halved loudness | Adding mass (extra plasterboard layer with Green Glue) |
| 15-20dB | Significant reduction, loud becomes moderate | Decoupled construction with mass and absorption |
| 25-30dB | Major reduction, clearly audible becomes background | Room-within-room, full soundproofing system |
| 40dB+ | Near isolation, sound barely detectable | Professional studio construction, double-leaf walls |
Sound Pollution Scenarios
Traffic Noise
Main path: windows. Secondary glazing or acoustic double glazing provides 15-25dB reduction. This turns constant traffic from clearly audible to background hum. Perfect silence requires window plugs that seal completely, which most people find impractical for daily use.
Upstairs Footsteps
Impact noise transmits through structure. Floating floor above achieves 18-25dB reduction. Suspended ceiling below adds 8-12dB. Combined treatment (if possible) achieves 25-35dB reduction, turning clearly audible footsteps into muffled thuds. Complete elimination requires structural changes beyond typical budgets.
Voices Through Walls
Airborne sound. Adding independent stud wall with proper construction achieves 25-35dB reduction. Normal conversation (60dB) becomes barely audible murmur (25-35dB). Loud argument (80dB) becomes equivalent to normal conversation level. Complete speech privacy requires 45dB+ reduction.
Music or Home Cinema
Requires addressing all surfaces and sealing completely. Full room treatment (walls, ceiling, floor, door, HVAC) achieves 35-50dB reduction depending on construction quality. Bass frequencies remain challenging—they require significant mass and cavity depth to control effectively.
Weak points limit overall performance. Spending £5,000 on wall soundproofing but leaving gaps around a cheap door wastes most of the investment. Sound takes the easiest path, so the weakest element determines the result.
Cost Ranges
| Treatment | DIY Materials | Professional Install |
|---|---|---|
| Door seals and sweep | £50-100 | £150-250 |
| Secondary glazing (per window) | £200-400 | £400-800 |
| Wall soundproofing (per m²) | £40-80 | £80-150 |
| Ceiling treatment (per m²) | £50-90 | £90-180 |
| Floating floor system (per m²) | £30-60 | £60-120 |
| Acoustic double glazing (per window) | N/A | £800-1,500 |
A typical bedroom (4m × 3m) with moderate soundproofing (walls, ceiling, door seals) costs approximately £1,500-2,500 for DIY materials or £3,500-6,000 professionally installed. High-performance studio-grade treatment of the same room costs £8,000-15,000+.
Planning Your Installation
Start by identifying which surfaces transmit the most sound and which type of noise causes the problem. Impact noise from above requires different treatment than airborne sound through walls. Testing with temporary measures helps verify the main transmission paths before committing to expensive permanent work.
Seal gaps and address doors and windows first. These quick fixes often provide noticeable improvement at low cost, and they're necessary regardless of other treatments. Poor seals around doors and windows can reduce the effectiveness of expensive wall treatments by 50% or more.
For walls and ceilings, balance performance against space loss and cost. Comprehensive treatments that provide 30dB+ reduction typically reduce room dimensions by 100-175mm per surface and require substantial budgets. Moderate treatments achieving 15-20dB reduction use less space and cost considerably less while still providing meaningful improvement for most situations.
Remember that soundproofing works as a system. The weakest element limits overall performance, so spreading your budget across all surfaces rather than perfecting one wall often produces better results. A room with moderate soundproofing on all six surfaces (four walls, floor, ceiling) and properly sealed penetrations outperforms a room with one perfectly treated wall and untreated weak points elsewhere.