You can hear next door's television through the party wall, so you search for a fix and find a wall of foam panels. It is an understandable mistake, and an expensive one. Foam, felt and mass-loaded vinyl are often sold side by side, sometimes by the same shop, but they solve completely different problems. Buy the wrong one and you will spend money, lose floor space and hear exactly the same noise as before.

What follows is a practical comparison of the three, judged on relative cost, how much depth they take up, how they behave in a fire, and whether you can install any of them in a flat you do not own.

The distinction that decides everything

Soundproofing means stopping sound travelling from one side of a wall to the other. That takes mass, separation (often called decoupling) and airtight sealing. Absorption is a different job: it softens sound inside a room so it stops bouncing around. It is the difference between a bare room and one with a sofa, curtains and a thick rug.

Foam and felt are absorbers. They are very good at killing echo and reverberation. They do almost nothing to stop a neighbour's bass coming through a shared wall, because they are light and thin. Mass-loaded vinyl is a barrier: thin, heavy, dense. It is the only one of the three genuinely aimed at transmission.

Even then, temper your expectations. Adding mass helps, but it takes a lot of it. MLV is typically around 5kg per square metre at roughly 5mm thick, and one layer stuck flat to a wall is a modest improvement rather than a cure.

Foam: cheap, soft and usually the wrong tool

Acoustic foam is open-cell polyurethane, sold as tiles, wedges or panels. It is the cheapest of the three per square metre, light enough to hang with adhesive strips, and available in any colour you like.

Where foam earns its place

• Taming a boomy corner behind a desk, microphone or small speaker setup
• Reducing flutter echo in a room with hard floors and bare walls
• Soaking up some of the sound of your own instruments, so you bother the neighbours less

None of that is soundproofing. It changes how your room sounds from inside, which is a real benefit if you record audio or simply find the space harsh, but it will not quieten next door.

Fire, and the flat problem

Untreated foam burns fast, drips and produces dense smoke. Some foam products are treated to meet fire performance standards and come with a documented Euroclass rating; plenty of cheap online listings have nothing at all. In a block of flats this matters a great deal. Wall and ceiling linings may fall under building regulations and under your landlord or freeholder's rules. If a product does not come with clear fire test documentation, do not put it on a wall, and if you are unsure, ask the freeholder or a qualified fire risk assessor before you buy.

There is a tenancy issue too. Foam tiles stuck down with adhesive frequently lift paint or plaster when removed, and that comes out of your deposit.

Acoustic felt: the polite middle ground

Acoustic felt is usually made from recycled plastic bottles, pressed into sheets around 9mm to 12mm thick. It is stiffer than foam, cuts cleanly with a craft knife and looks more like a design decision than a home studio. Wool felt is the natural-fibre alternative. Both cost more than basic foam and considerably less than mass-loaded vinyl.

Felt absorbs mid and upper frequencies well, so speech, television chatter and kitchen clatter lose some of their edge. It makes a room feel calmer. It will not stop bass, and it will not stop much passing through a solid wall.

Good uses include a panel behind a sofa or bed, a soft headboard, door linings and a decorative pinboard that quietly does some work. Some felt panels carry a documented Euroclass B rating; ask the supplier for the test paperwork and keep it.

Fixing is where renters get caught out. Spray adhesive leaves residue, staples leave holes. A removable timber or MDF frame, or a tensioned hanging system, is far kinder to a wall you do not own.

Mass-loaded vinyl: thin, heavy, effective

MLV is a flexible sheet of dense mineral-filled PVC. It is the heaviest and by some distance the most expensive of the three, and the only one designed to block sound transmission. Thicker versions add more mass in the same footprint.

It is best used as part of a build-up rather than on its own: laid over a wall before a layer of plasterboard goes on top, wrapped around pipework, or added to a stud wall. It can be used on a door, but check your hinges first. Heavy sheets strain them, and a sagging door is a repair bill.

Two caveats. First, MLV only works if you seal it. Gaps at the edges, around sockets and along the skirting let sound straight past. Second, PVC-based sheets produce smoke when they burn, so check the manufacturer's fire documentation and only use it where they say it is suitable.

Comparing the three

• Cost per square metre: foam is cheapest, felt sits in the middle, MLV is the most expensive by a wide margin.
• Thickness: foam and felt run from about 9mm to 50mm; MLV is usually 2mm to 10mm but far heavier.
• What it actually does: foam and felt absorb sound within a room; MLV blocks sound passing through a surface.
• Fire performance: all three need documented ratings. Foam is the one to be most careful with.
• Rented flat: felt and foam are easier to remove, though adhesive can wreck the finish. MLV is heavy and semi-permanent.
• Best value first step: none of the above. Sealing gaps beats all three.

What is realistic when you rent

You have limits: no structural work, no drilling without permission, no permanent alteration, and a deposit at stake. Work within those and you can still make a difference.

1. Walk the room and find the leaks. Gaps around a shared front door, an unfilled pipe sleeve, a loose skirting board or an open chimney flue can carry more noise than the wall itself.
2. Fill those gaps with a proper acoustic sealant or a brush strip, not expanding foam.
3. Add soft mass: a heavyweight rug, thick lined curtains, a full bookshelf pushed against the party wall.
4. Hang felt panels on your side of the wall. This mainly improves your own room, which is still worth having.
5. Consider MLV only if you can build a removable, sealed frame and have written permission from your landlord.
6. Photograph everything before and after, and keep your fire documentation in a folder.

If noise from a neighbour is persistent, disruptive and unreasonable, it may be a statutory nuisance rather than a decorating problem. Your council's environmental health team handles those reports, and tenancy rules differ across the UK, so it is worth taking advice on your specific situation before spending money.

Start here

Do not begin with materials. Begin with a torch and a tube of acoustic sealant, working around every edge you can reach. Then add soft furnishings and a felt panel or two, which will improve your room even if the wall stays stubborn.

Reach for mass-loaded vinyl when you have permission, a budget and a plan for sealing it properly. Leave foam for the corner behind your desk, where it does a genuinely useful job. And if you want a quiet flat more than a quiet room, be honest: the honest answer may be a professionally built partition, or a different flat.

Photo: John Taran / Pexels