Sound coming in or going out (sound insulation)

Noise from next door or through the wall — how to fix it

Q: Why does the sound get through?

A light wall — a single layer or thin boards have little mass, so sound passes easily Gaps — back-to-back sockets, joints at the floor or ceiling, the gap under a door. Small openings let a lot of sound through Flanking — sound travels around the wall through the ceiling void, the structure or connected pipes, even when the wall itself is good

6 min read · Written by our team · Updated 26 Sept 2026

In short

Most noise from a neighbouring room or house comes through the wall, through gaps and by indirect (flanking) paths such as a shared ceiling void. What works is turning the wall into a sound-insulating system: heavier boards, separated framing, insulation in the cavity and every gap sealed. Absorption panels on the wall help with echo but do not stop noise from next door.

Does this match your problem?

You hear voices, TV or music from the next room or the house next door
It is louder at certain spots — near sockets, at the ceiling or floor edge, or around a door
A single-layer partition was built and sound passes through easily
In a townhouse or semi-detached house, sound comes through the shared wall

Why does the sound get through?

A light wall — a single layer or thin boards have little mass, so sound passes easily
Gaps — back-to-back sockets, joints at the floor or ceiling, the gap under a door. Small openings let a lot of sound through
Flanking — sound travels around the wall through the ceiling void, the structure or connected pipes, even when the wall itself is good

The main routes for noise from next door: through the wall, over the ceiling and through gaps

Which fix: sound insulation, not absorption

Here the sound is travelling through the wall, so the answer is sound insulation. If your problem is echo or reflections inside the room, see Echoey room instead.

Sound coming in from outside, or going out of your room You need sound insulation Fix sound through walls Echo, reflections, speech hard to understand You need sound absorption Fix an echoey room

Absorption panels make a room less echoey, but they do not stop sound passing through a wall

What a sound-insulating wall is made of

Part of the system	What it does	Material
---	---	---
1–2 layers of board each side	Adds mass, blocks sound	Boards specified by the wall-system maker
Separated framing	Reduces sound carried from one face to the other	Framing to the wall system
Cavity insulation	Reduces resonance in the cavity and improves the system	Stone wool or glass wool
Sealing	Closes the paths sound leaks through	Sealants and joint fillers

Sound insulation ratings (STC or Rw) belong to the whole wall, not to the insulation. See What is STC?

Products used in sound-insulating walls

ROCKWOOL Safe 'n' Silent Pro stone wool slab

Sound insulation

Why it fits: Stone-wool slabs made for the cavity of drywall partitions and above ceilings in sound insulation work

View details

SCG Cylence ZoundBlock wall insulation

Sound insulation

Why it fits: Cavity insulation used in SCG's sound-insulating drywall systems

View details

Before you start

The result belongs to the whole system — insulation alone in a single-layer wall may do little
Small gaps can undo a well-designed wall
Low-frequency sound (bass, machinery) is harder to block than speech
If the noise comes through windows or doors, those must be treated too
Condos: check the building's rules before altering walls

Frequently asked questions

Do absorption panels on the wall stop noise from next door?

Very little. They reduce reflections inside the room but add no mass and do not close the paths sound travels through.

Can insulation be added to an existing wall?

If it is a hollow partition, one face can be opened, the cavity filled and a new board fitted. The result depends on the existing wall and on sealing. Send us photos and we'll take a look.

Common problems

Walls Homes

Understand this better

Sound and acousticsSound insulation vs sound absorptionWhy panels on the wall do not stop noise from next door Sound and acousticsSound transmission and flankingSound travels through the wall, leaks and flanking paths such as ceilings, floors and ducts, so site results are usually below lab ratings.Sound and acousticsWhy cavity insulation improves sound insulationCavity insulation absorbs sound bouncing inside a double-leaf wall and works fully only in a correctly built wall system.Terms and valuesWhat are STC and Rw?A rating for the whole wall, not for one material

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