The short answer: noise from upstairs comes in two forms, and they need different fixes. Airborne noise — voices, TV, music — is largely solved by filling the joist bays and sealing the gaps in the ceiling plane. Impact noise — footsteps, dropped objects, chair legs — travels through the structure itself, and insulation alone will not stop it. If footsteps are your problem, you need to decouple or soften the floor above, not just add insulation.
A ceiling between two heated floors is a different problem from an attic or a basement. Both sides are conditioned space, so thermal performance barely matters. What people actually want from a between-floors ceiling is quiet — and that is where most advice goes wrong, because it treats all noise as one thing.
Impact Noise vs Airborne Noise
These are measured separately for a reason. They travel by different routes and respond to different fixes.
| Airborne noise | Impact noise | |
|---|---|---|
| Examples | Voices, television, music | Footsteps, dropped objects, chairs scraping |
| How it travels | Through air, then through gaps and the assembly | Through the structure — floor into joists into ceiling |
| Rated by | STC (Sound Transmission Class) | IIC (Impact Insulation Class) |
| Does insulation help? | Yes, substantially | Only marginally on its own |
| What actually fixes it | Fill the cavity, seal every penetration | Decouple the ceiling, or soften the floor above |
Most people complaining about "noise from upstairs" mean footsteps. That is impact noise, and it is the harder of the two.
Why Insulation Alone Does Not Stop Footsteps
When someone walks on the floor above, the impact puts energy directly into the subfloor. That energy travels down the joists — solid timber, rigidly connected to the ceiling below — and the ceiling drywall then radiates it into your room like a drum skin.
Insulation sits in the cavity between those two rigidly connected surfaces. It absorbs some of the airborne component of the sound, but it does nothing about the direct mechanical path through the joists. That path is the reason a well-insulated ceiling can still transmit every footstep.
This is worth knowing before you spend money: if you insulate a joist bay expecting footsteps to disappear, you will be disappointed. Insulation is the right first step for voices and television. Footsteps need something else on top of it.
What Realistic Numbers Look Like
A typical bare timber floor assembly — subfloor above, drywall below, empty joist bays — performs poorly on both counts. Adding cavity insulation improves the airborne figure noticeably and the impact figure only slightly. Decoupling the ceiling from the joists produces the largest single improvement in impact performance, and soft floor covering above is the cheapest meaningful gain of all.
For context on how these ratings work and what different wall assemblies achieve, see our guide to spray foam for soundproofing.
Step 1: Fill and Seal the Ceiling Plane
This is where insulation earns its place, and where spray foam has a genuine advantage over batts.
A ceiling is full of holes: recessed light housings, duct boots, wiring penetrations, gaps where the drywall meets the top plate. Every one of those is a direct airborne path, and batt insulation does nothing about them — it sits beside the hole, not in it.
Spray foam expands into those gaps and seals them as it insulates. In practice, sealing penetrations often does more for airborne noise than the insulation depth itself.
Use open-cell foam here if you can. Its open structure absorbs sound; closed-cell is denser and rigid, and rigidity is not what you want in an assembly where you are trying to stop vibration. Thermal performance is irrelevant between two heated floors, so the usual reason to pay for closed-cell does not apply. See open-cell vs closed-cell spray foam for the full comparison.
Step 2: Decouple the Ceiling
This is the step that addresses footsteps, and the one most people skip.
Decoupling means breaking the rigid connection between the joists and the ceiling drywall so vibration cannot pass straight through. The common methods are resilient channel or hat channel on isolation clips: thin metal channel fixed across the joists, with the drywall screwed to the channel rather than to the timber.
Two details decide whether it works:
- Nothing may short-circuit the channel. A single screw that goes through the drywall, past the channel and into a joist reconnects the assembly and undoes the whole system.
- The cavity should be insulated first. Decoupling creates an air gap, and an empty gap resonates. Filling it is what stops that.
Step 3: Soften the Floor Above
The cheapest and often most effective impact fix is not in the ceiling at all — it is on top of the floor.
Carpet with a decent underlay absorbs impact energy at the source, before it ever enters the structure. If the room above has hard flooring and you have access to it, an acoustic underlayment under the finished floor does the same job. Even rugs in the high-traffic paths make an audible difference.
If you can only do one thing about footsteps and the floor above is accessible, do this one.
Common Mistakes
- Expecting insulation to solve impact noise. It will not, on its own. Set expectations before you open the ceiling.
- Leaving recessed lights unsealed. A row of open can lights is a row of open holes between the two rooms.
- Screwing through resilient channel into the joist. One screw can undo the entire decoupling layer.
- Using rigid foam board or closed-cell where absorption is wanted. Density helps block; open structure helps absorb. Between floors you want absorption.
- Ignoring flanking paths. Sound also travels down shared walls, through ducts and around the perimeter. A perfectly treated ceiling will not help if the noise is arriving through a duct run.
Frequently Asked Questions
Will insulating between floors stop footsteps from upstairs?
Not by itself. Footsteps are impact noise, transmitted through the joists. Insulation reduces the airborne component; stopping the impact component needs decoupling the ceiling or softening the floor above.
Does insulation between floors help at all?
Yes — substantially for airborne noise like voices, television and music, and it is a necessary part of any decoupled assembly. It is the right first step, just not the whole answer.
Open-cell or closed-cell foam for a ceiling between floors?
Open-cell. It absorbs sound better, and the higher R-value of closed-cell is irrelevant between two heated rooms.
Do I need to insulate a ceiling between two heated floors for warmth?
No. Both sides are conditioned space, so there is almost no thermal benefit. The reason to insulate an interior ceiling is sound.
What is the cheapest way to reduce noise from upstairs?
Carpet and underlay in the room above, if you have access to it. It addresses impact noise at the source and costs a fraction of opening a ceiling.
Can I add insulation without taking down the ceiling?
Only by drilling and blowing in loose-fill, which fills the bay but does not seal penetrations or decouple anything. If the ceiling is coming down anyway, that is the moment to do the job properly.
The Bottom Line
Fill and seal the ceiling plane and you will noticeably cut voices, television and music from upstairs. Add decoupling and soft flooring above and you address footsteps as well. Skip those two and no amount of insulation will make the ceiling quiet.
If you are ready to seal the ceiling plane, see the ixirpro Spray Foam Insulation Kit.