Impact noise, and the tenancy below you
Drop tables and dropped weights send sound through the structure, not the air. It is the one acoustic problem that cannot be fixed from the other side.
The short answer
Most acoustic work in a clinical fitout is about conversation: keeping what is said in one consulting room out of the next. That is airborne sound, and full-height partitions with cavity insulation and a sealed door handle it well.
Key points
- Airborne noise and impact noise are different problems with different solutions.
- Carpet does not fix impact. Neither does treating the ceiling in the tenancy below.
- An isolated floor build-up works, costs real money, and eats ceiling height.
- Resolve it during due diligence. After a complaint you are negotiating, not designing.
Most acoustic work in a clinical fitout is about conversation: keeping what is said in one consulting room out of the next. That is airborne sound, and full-height partitions with cavity insulation and a sealed door handle it well.
Impact noise is a different mechanism, and the practices that run into it are the ones that had no reason to think about acoustics at all.
Why it behaves differently
When a chiropractic drop piece releases, when a loaded barbell lands on a rehab floor, or when someone jumps down from a plyometric box, the energy goes into the slab. From there it travels through the building structure and radiates out of the ceiling, walls and columns of the tenancy below as a low, percussive thud.
The tenant downstairs cannot tell where it is coming from and cannot do anything about it. The sound is not arriving through the air, so absorbing it in their space achieves nothing. Their ceiling is not the path; it is the loudspeaker.
What does not work
- Carpet. Helps a little with footfall, does nothing meaningful for a dropped weight or a drop table.
- Treating the ceiling below. Sometimes offered as the cheap fix. It addresses airborne sound in that space, not structure-borne energy already in the slab.
- Rubber mats laid loose on the floor. Better than nothing under free weights, and often mistaken for a solution. They reduce the peak but do not isolate.
- Asking staff to be careful. This has never once worked.
What does
The effective answer is to stop the energy entering the structure, which means an isolated floor build-up: a floating floor on resilient mounts or an acoustic underlay system designed for impact, under the zone where the load actually lands.
Three things follow from that, and all three want to be known before you sign a lease.
It costs real money, and it is a line item rather than a rounding error. It consumes ceiling height, typically somewhere between 50 and 100 millimetres depending on the system, which matters a great deal in a tenancy already at 2.7 metres clear. And it has to be set out where the load lands, which means the equipment layout has to be settled before the floor is built, not after it.
Retrofitting isolation under equipment that is already installed means removing all of it, and at that point you are paying twice.
The lease question nobody asks
Impact noise is usually a lease problem before it is an engineering one, and the clauses that govern it are already in the document you are about to sign.
Most commercial leases contain an obligation not to cause nuisance and a covenant of quiet enjoyment running to other tenants. A neighbour with a legitimate complaint is not asking you politely; they are asking the landlord to enforce a term. Practices have been required to stop using equipment, or to fund isolation works after the fact, on the strength of exactly that.
So the questions during due diligence are practical ones. What is directly below this tenancy, and what do they do? Is the slab suspended or on ground? What are the building’s hours, and does anyone below need quiet during yours? Would the landlord permit a floor build-up at all, given it changes floor levels and thresholds?
A ground floor tenancy on a slab on ground removes the problem completely, which is why it is worth paying attention to for a chiropractic practice or an exercise physiology clinic in a way that it simply is not for a consulting practice.
Sources and further reading
AS 1428.1 and NCC provisions read alongside how impact isolation is specified in practice, and the nuisance and quiet enjoyment terms that appear in standard commercial leases.
Source for AS/NZS 4815 and 4187 reprocessing, AS 1428.1 access and AS 1668.2 ventilation. The standards themselves are purchased, not free.
The National Construction Code: building classification, fire separation, egress, sanitary provisions and access.
The Retail Leases Act 1994 framework and the disclosure a landlord owes a tenant, including on make good and outgoings. Every state has its own equivalent.
Questions
Does carpet stop impact noise?
No. Carpet helps slightly with footfall but does almost nothing for a dropped weight or a chiropractic drop table, because that energy goes into the slab rather than through the air. The effective answer is an isolated floor build-up under the zone where the load lands.
Can the tenant below fix it from their side?
Not really, and it is worth understanding why. The sound is not travelling through the air into their space; it is travelling through the structure and radiating from their ceiling and walls. Absorptive treatment down there addresses airborne sound, not structure-borne energy already in the slab.
How much ceiling height does an isolated floor take?
Typically 50 to 100 millimetres depending on the system. That matters in a tenancy already at 2.7 metres clear beneath the services, which is the practical minimum for any space where people exercise or work overhead.
Should I just look for a ground floor tenancy?
For a chiropractic practice with drop tables, or an exercise physiology clinic with free weights, a ground floor slab on ground removes the problem entirely and is worth a genuine premium. For a consulting practice it is not a consideration at all.
Can a landlord stop me using equipment because of noise?
It is a real risk. Most leases carry an obligation not to cause nuisance and a quiet enjoyment covenant running to other tenants, so a neighbour with a legitimate complaint is asking the landlord to enforce a term rather than asking you a favour. Practices have been required to stop using equipment or to fund isolation works afterwards.
Send us the floor plan
A site assessment tells you what the tenancy can take and what it will cost to get there, ideally before you have signed for it.