Insulating the wall later – 8 effective tips

Unfortunately, it is often only after you have moved into your new home that you notice how thin the walls are. Whether noises from the kitchen or the loud neighbors next door – if the walls are very sound-permeable, it can be really annoying.

But there are some things you can do to make a wall much more soundproof afterwards. You can find out exactly what here.

To add soundproofing to a wall, you can place heavy furniture in front of the wall (bookcase, wardrobe, etc.) or attach acoustic foam, insulating wallpaper or soundproof curtains to it. The most effective way of soundproofing is with an additional facing shell made of heavy gypsum boards and insulating materials.

Basic Principles

Before you start soundproofing the wall, let’s first understand what the basic principles for effective soundproofing are. With this understanding, you can then specifically select the method that is most effective for your wall.

sound absorption

Some materials can absorb sound by absorbing the sound waves and converting them into kinetic energy. This reduces the noise. A good example of such a material is acoustic foams.

Soundproofing through absorption is particularly effective at higher frequencies. Unfortunately, it is less effective on low, bassy frequencies, as these sound waves have more energy and are therefore more difficult to convert. Significantly thicker material is needed to reduce deep bass through absorption. This takes up a lot of space and can quickly become impractical.

Mass

Sound waves are transmitted through vibrations. In order for a solid object (e.g. a wall) to transmit sound, the object itself must be made to vibrate.

The more mass the object has, the harder it is to make it vibrate. In order for sounds to get through, they must have more energy (higher volume and/or lower frequency).

Mass is the ultimate when it comes to soundproofing. So a heavy wall is usually better than a thick (but lighter) wall.

Eight effective tips

So let’s move on to the steps you can take to make your wall more soundproof.

1. Put the bookshelf or wardrobe against the wall

A bookshelf can effectively improve the noise protection of the wall. Due to their high mass, the books can keep out the sound well and sometimes also absorb it. The fuller the shelf is packed, the better. Because where there are gaps in the shelf, the noise can still get through unhindered from the wall to your ears.

A wardrobe on the wall can also be very effective. The bigger and fuller the closet, the better. But that shouldn’t tempt anyone to excessive clothing shopping!?

2. Attach soundproof curtains

Soundproof curtains are characterized by the fact that they are particularly heavy and thick. This allows them to keep out and absorb some of the noise. They are usually used to reduce noise coming through the window. However, they can also be easily attached to the wall, where they are just as effective.

They reach their limits with particularly loud noise or deep bass. But they offer the additional advantage that they significantly reduce the reverberation in the room. The result is quieter and more pleasant room acoustics. Find out more about how effective soundproof curtains really are here.

3. Attach acoustic foam sound absorbers

Acoustic foam is very often used to improve room acoustics and reduce sound transmission inwards and outwards. So-called sound absorbers or sound insulation mats consist of such foams and can be easily glued or screwed to the wall.

Sound absorbers can be quite effective at dampening light to medium noise. They also significantly reduce the reverberation in the room, which means that noises are perceived much less intensively.

It should be noted, however, that such sound absorbers can only be really effective if they cover most of the wall. So a square meter or two of sound absorbers on a 10 square meter wall is unlikely to make a significant improvement.

In addition, the same applies here: the thicker the material, the better it can absorb the sound.

4. Install mass loaded vinyl mats

Unlike acoustic foams, mass-loaded vinyl’s high density allows it to stop rather than absorb sound. It is often more effective when it comes to blocking out loud noises and bass.

Mass-loaded vinyl mats can be attached directly to the wall with no gaps. This makes the whole wall more solid and soundproof.

All the above methods can be combined very well! For even more effective soundproofing, you can first attach acoustic foam or vinyl mats, then hang soundproof curtains over them and finally put a bookshelf in front of the wall.

5. Check door

If the wall you’re trying to insulate has a door, it’s important to first check that the door isn’t the real problem. Noise can usually get through the door much more easily than through the wall. Also check out this article to learn how to soundproof your door.

6. Attach insulating wallpaper

Special wallpapers made of cork and other heavy material are also used to make walls soundproof. The wallpaper can be painted over or papered over again so that it can no longer be seen at all.

7. Acoustic images? – Better not.

Sometimes you can find very positive reviews on the Internet about acoustic images and the supposedly high effectiveness for sound insulation. Unfortunately, one has to say that the positive opinions are probably more due to better room acoustics than to real sound insulation.

In principle, acoustic pictures are the same as the sound insulation mats mentioned above, because they are made of acoustic foam. So they can absorb sound. But here’s the problem: In order for this to be really soundproofing, the majority of the wall would have to be covered with acoustic pictures!

As a rule, however, there are probably a maximum of two to three medium-sized pictures on the wall. They certainly reduce the reverberation in the room and thus improve the room acoustics. Unfortunately, when it comes to blocking noise inwards or outwards, they tend to be less effective.

8. The professional tip: build a facing shell

If you are really serious and spare no expense or effort, you should build a facing wall on the wall – this is definitely the most effective method.

In principle, a facing shell is an additional wall that is attached to the existing wall. This second wall usually consists of sheetrock on the outside and insulating material on the inside. Mineral wool is usually the best insulation material. As a result, the wall already absorbs significantly more sound.

However, to make the facing shell particularly soundproof, it can be lined on the inside with mats made of mass-loaded vinyl. In addition, instead of ordinary plasterboard, you can use special soundproof plasterboard. This gives the wall significantly more mass and better blocks sound waves.

You can find a somewhat detailed explanation of how to build a facing shell in this article from Baustoffwissen.de. This YouTube video might also be very helpful.

CONCLUSION

There are some easy ways you can make a wall significantly more soundproof. In particular, heavy furniture on the wall (bookshelf or wardrobe) as well as acoustic foams, insulating wallpaper and soundproof curtains can be very helpful – especially if you combine them with each other. However, if you are looking for maximum sound insulation, you should consider adding a facing shell with heavy plasterboard and sound-absorbing insulating materials to the wall.