Why can the flat below hear every footstep, and what actually reduces it?
Footstep noise is impact noise, and it enters the structure rather than travelling through the air. The order of things that actually reduce it, and the three leaks that undo the work.
- Difficulty
- intermediate
- Time
- 2 hr
- Read
- 3 min
- Safety
- caution
Short answer
Impact noise is stopped at the top of the floor, before the energy gets into the structure — a soft covering on a genuine acoustic underlay does more than anything else a resident can do. Then seal the perimeter gap, the pipe penetrations and any downlighter holes in the ceiling below. Adding mass and building a floating floor come after that, and both are much bigger jobs.
Two different problems get called noise from upstairs. Airborne noise — speech, television, music — travels as sound waves and is reduced by mass and by sealing gaps. Impact noise — footsteps, dropped objects, chair legs, a washing machine — is vibration put directly into the structure, and no amount of mass in the ceiling below fixes it efficiently once it is in there. Almost everything that works, works at the top surface.
Safety
Step by step
- Establish which noise you actually have.If you hear heels, thumps, furniture moving and the washing machine, that is impact. If you hear conversation and television, that is airborne. Most complaints are impact, and most attempted fixes are aimed at airborne.
- Start at the top of the floor.A carpet on a good crumb rubber or dense felt underlay is by far the most effective thing a resident can do about impact noise, and it is reversible. Where a hard covering has to stay, a dedicated acoustic underlay under it — sold with a published impact reduction figure — is the equivalent.
- Do not confuse acoustic underlay with thick underlay.Thickness and softness are not the same as acoustic performance. Products intended for this purpose publish a laboratory impact sound improvement figure, and that number, not the millimetres, is what you compare.
- Seal the perimeter gap.A floating floor stops short of the wall, and that gap is often a direct path down the wall cavity into the room below. An acoustic sealant or a flexible perimeter strip closes it without pinning the floor down.
- Seal the penetrations.Pipes, cables and soil stacks passing through the floor almost always go through an oversized hole. Packing with mineral wool and sealing with an acoustic sealant costs very little and closes a real path.
- Deal with the downlighters below.Every recessed light in the ceiling below is a hole cut through the sound barrier. Acoustic and fire-rated hoods designed for the fitting restore some of it, and the fire performance matters as much as the sound.
- Then consider mass and isolation.Adding a resiliently mounted layer of plasterboard below, or building a proper floating floor on a resilient layer above, does work — but both lose ceiling or floor height, both are significant jobs, and in a flat both may need consent.
- Attack the sources at the same time.Felt pads on every chair and table leg, a decent anti-vibration mat under the washing machine, soft-close on cupboards, and rugs on the main walking routes. This is unglamorous and it removes a surprising share of the actual complaints.
Common mistakes
- Filling the ceiling void below with loft insulation to stop footsteps — Soft insulation reduces the drum-like resonance of the void slightly, but impact energy is travelling through the joists, and insulation does not touch that path.
- Laying a hard floor in a flat with a foam underlay and hoping — Standard foam laminate underlay is for cushioning and levelling, not for impact isolation. It is the change most likely to cause a neighbour complaint and, in many leases, a breach.
- Sealing everything but leaving the perimeter gap open — One unsealed path can undo most of the benefit of everything else. Sound leaks behave like water leaks.
Questions people ask
Does the building regulation standard apply to my flat?
The sound insulation requirements apply to the building as built or converted, at the standard in force at the time. An older conversion may lawfully perform far worse than a new one. That is why the lease, rather than the regulations, is usually the practical lever between neighbours.
What if the noise started when the flat above took up its carpet?
That is the common story, and it is often a lease matter. Raise it with the freeholder or managing agent, in writing, referring to the covenant about floor coverings if there is one. Councils treat persistent domestic noise as a statutory nuisance question, which is a slower route.
Is a rug enough?
Rugs on the main walking routes genuinely help and cost nothing to try. They do not match a fitted carpet on acoustic underlay because the paths at the edges of the room remain open.