Best DIY material to make a sound-proof bedroom door

I have an autistic son & very often there's crying / tantruming from
him with adults shouting at him.

My mid teen daughter is often affected by this noise, be it she is
at rest or studying though she coops herself up in her bedroom
almost all the time.

I've stayed in her bedroom before & was certain all those noises
came through the wooden door of the bedroom: no noise via
the walls & windows.

I've pasted rubber matts on the wooden door but the noises are
still coming thru the door: I tried rubber matts as I've laid rubber
matts in our living room where our neighbours downstairs often
complain of noises whenever my son jumps on the floor & this
has drastically reduced the noises (& complaints) from the
neighbours downstairs.

Besides getting professional contractor that will cost me quite a
bit, is there any other material that I can 'paste' over the wooden
door to cut down on the noises?  What do people normally pad
their drumming & guitar rooms (so that the noises don't bother
the neighbours) ?

I've read a Net posting that pasting carpets on the walls & doors
help with such drumming/cymbal & guitar rooms.  Any truth in
this (before I invest in carpets) ?

I did buy a headphone & ear stubs but my daughter doesn't
often put them on as she doesn't find them very comfortable
& sometimes not in time to put them on : can't predict when
my son / adults' noises will surface :

I don't plan to invest in professional sound-proofing that costs a
lot as we won't be staying at this place for very long.
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sunhuxAuthor Commented:
I did not go further to get the 3M earmuffs as the 'Howard Leighs'
model did not meet my daughter's expectation: when she sleeps
with it, can feel something & may drop off when she rolls a lot:

So what the most sound-proof materials that  are easily-available out
Use polystyrene sheets:

bubble wrap:

Or even cardboard boxes unfolded and layered on walls will help.

All of these are cheap and good D.I.Y. methods.
sunhuxAuthor Commented:
Thanks Michael, will try polystyrene out first.

In the event it does not work, will a sound-proofing
curtain or an anti-acoustic foam be more effective?
I'm exploring :

Just surprised that the 3cm thick wooden door allows so much
noise to go through it
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sunhuxAuthor Commented:
one more query:
would a 1cm polystyrene help as good as a 2cm polystyrene?
Ie the thicker the polystyrene, the better it blocks the sounds / noise ?
I listed from most effective to cheapest.

"would a 1cm polystyrene help as good as a 2cm polystyrene?"

Although the thickness will help but a more effective way is to use layers with an air space between them.

Recommend: 1 polystyrene layer + bubble wrap layer + another polystyrene layer for greatest sound proofing at the least cost.

Some say that foam is better?, but it absorbs moisture, dust, smells & other unwanted stuff.
So stay with non absorbing materials "polystyrene + bubble wrap)

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I'd suggest using wavy foam, like in the Link below:

But it shouldn't be too thin (the example in the link looks a bit thin), I'd go for something 5 cm thick or so. The wavy structure should absorb the noise better.  Make sure that if the noise comes from the outside of the door, to also put those foams on the outside, and the wavy structure should point away from the door (the flat part of the foam is where you paste it to the door).

Also put some foam between the door and the wall, so there isn't any gap.
( I worked as a teacher for autistic children )

The use of wavy foam will surely be a bad visual affect for all involved.

Autistic children are very sensitive about their surroundings, so change as little as possible.
Polystyrene if installed carefully can appear as normal walls / doors.
If your son likes to draw or use crayons then let him decorate his room on paper pasted over the Polystyrene.
From my understanding, the door in Question is to the daughter's room, who isn't autistic, to protect her from the outside noise caused by her autistic brother, so I don't think the visual appearance would matter too much. Besides that, I think the wavy foam would actually look better, as it gives the door a Hi-tech-type "Audio Studio" look.
You son will see any insulation used?  ... yes?
To be effective it will need to be on either or both your sons inner door side and your daughters outer door side.
Wavy foam is most effective on the noise emitting side of walls / doors.
Wavy foam surroundings can be perceived as being scary to children, particularly to families with autistic children.

This is my advice as a long term autistic children care provider.
Sound radiates through the air, including halls, open doors, and gaps around doors.  It conducts through solid material like floors, ceilings, and walls.

As Michael-Best as suggested, it would be best to block the noise at the source and destination.

Something quick you might try is to tack a poly-fil quilted bedspreads to the inside of the relevant doors (away from the frame) so that they cover the doors and all the gaps when the door is closed.  Thick carpets in the source area would also help.

Another thing you might consider is using a white-noise generator (they are really just fans) like the kind used in psychiatrist waiting rooms.  They are less than $50.
sunhuxAuthor Commented:
If pasted in the interior of the bedroom door, my son won't be able to
see it.  If pasted on the outside, he may tend to peel it but don't think
he will get 'annoyed' by it, just that he will destroy it in no time.

He likes to peel & scratch.  He's seen wavy foams in exposed mattresses
before, not scared of it, just that he likes to peel

This white very lightweight material that breaks into tiny bits:
is that styrofoam & does it help insulate the noise?  I will try this
as I could get it at the wet market.

One local supplier I just called today told me his polystyrene sheets
are good to be placed on floors & will considerably reduce noises
when kids jump on the floor but not on the door.  Just curious.
This supplier's link is  & in particular it's the
Damtec & Euroflex acoustic sheets that he's referring to:
very economical for 3 feet x 6 feet of 2cm thick, it's only US$18
You can also paste it on the door's interior, it just won't be as effective that way.

Maybe you could buy some excessive foam for him to play around with so he doesn't peel it off the door.
sunhuxAuthor Commented:
> ... the door in Question is to the daughter's room ...
     Yes, the above is correct

> ... who isn't autistic, to protect her from the outside noise caused by
>     her autistic brother ...
     Yes, the above is correct

I live in high-rise apartment (more than 98% of the population here live
in high-rise buildings), thus the frequent complaints from the neighbours
downstairs when my autist son jumps on the floor: managed to pad some
parts of it with rubber mats & that helps.

I'll be moving to another high-rise apartment in future so I guess I may
as well start planning now how to reduce noises from the wailings,
cryings, shoutings & jumping from affecting the neighbours : I certainly
can get a sound-proofing contractor to do this but some contractors
are not that reliable: after they have installed & there's still noise going
through, it's hard to get them to improve it further.

As I'm getting quite a few responses here, thought if anyone would
care to assess if the following contractor's method is good:

Ideally if the contractor has a showroom & let me do some shouting
at the other side of the door/windows, that will be surefire way of
testing it out
Please rule out that he may not eat or inhale the scratched insulation?

If you cannot, then insulation outside his reach or non toxic or a hard surface interior insulation will be required.

Probably smooth surfaces do not get scratched?   If this is correct, then polystyrene sheets covered with colorful paper may solve both the noise and the peeling & scratching?

Hope this helps.

I was typing this during your last post, so if you give me some time I shall update my advice.
Your updated feedback indicates that further advice & feedback is needed.

sunhuxAuthor Commented:

Just checked out the above device & it says
"Voltage - 120V - for use in North America only".

My place is using 220-240V, so guess it won't work here
Just a quick look at the website suggests that the contractor is competent (and probably expensive).
The windows won't help your situation much, but a pair of double-glazed, tightly gasketed doors is probably the best you can do.  I would be interested in what you get for prices.

And you can only get sound reduction, not elimination.
That company (Marpac) is just the first example I found.  

They have voltage converter transformers:

and European models:
sunhuxAuthor Commented:
The foam may peel from time to time & I plan to seal it (if I'm using a styrofoam)
in a plastic layer so that it doesn't fly all over the places.

There's a chance he may sniff or put it into his mouth
sunhuxAuthor Commented:
Thanks for the voltage converter.

The glass panels are filled with 'heavy gases' : wonder if they will leak
over time & needs to be topped up.

The windows is for the future apartment : reduce son's (& adults') voices
from affecting neighbours.

If only the contractor will indicate by how many decibels the noise
will be reduced, just like the Howard Leigh earmuff:
sunhuxAuthor Commented:
I've just got a few pieces of this white styrofoam of about 2cm thickness
& paste them to the interior surface of my daughter's bedroom door:
only have enough to paste two thirds of the door : so far, the noise
reduction only reduced a bit : would say about 75% of the noises'
volumes can still be heard: will seal the remaining one third of the
door & see how it goes.

I did not leave any gap between the styrofoam sheets & the wooden
door (with no bubble wraps in between the styro sheets & the door's
interior surface)
It seems that comments and your feedback are off track to your questions opening & closing objectives:
"Best DIY material to make a sound-proof bedroom door"
"I don't plan to invest in professional sound-proofing that costs a
lot as we won't be staying at this place for very long."

Please consider only the D.I.Y. suggestions as the correct solution for this.
Open a new question if you are wanting / asking for professional service.

D.I.Y solutions that do not cause damage to your rooms should be a cost consideration.

With no glue, staples, pins, etc. a layer of bubble sheet hanging over the top of the door (doors) that fully covers both sides is cheap, practical, effective, and D.I.Y.
You can then attach further suggested sound proofing on either or both sides of the bubble sheet with staples, glue, etc. to increase the effect.

To stop him scratching at it use an outside layer of cardboard or a stronger material.
sunhuxAuthor Commented:
As requested, the price of the soundproof door from contractor below:

It's US$440/door (if we make 3 doors) to US$490 (if we make only 1 door).
Contractor says it will block 85% of the noise (so not 100%) & it's hinge
type (can't do sliding as noise can go thru the sliding gaps; I prefer
sliding as it save space).  The gas doesn't need to be topped up
My last comment was in the process of typing, thus I did not to see your latest feedback:  
"sunhux2014-10-23 at 01:48:29ID: 40397447"

Noise can also enter from the air spaces around the doors edges.
Although it is usually used as heat insulation this product, if used around the  doors edges will be an effective noise insulator:

Self-Adhesive Foam Weatherstrip Seal
I'm curious to know what the internal walls in your high-rise apartment are made from.

There will always be load-bearing walls that need to be built from something solid like a single layer of bricks, but other internal walls are commonly made from sheets of Gyproc or Drywall (plasterboard - names differ by country) nailed or screwed on either side of a wooden frame constructed from 2 or 3 inch wood, and are really nothing more than partitions through which all the electrical cables pass.

In cold climates the gap between these plasterboards is usually packed with fireproof thermal insulation material like glass fibre matting or Rockwool which helps to reduce sound between rooms, but in warmer climates it is probable that there is just an air gap through which sound passes easily.  You still get sound conducted through the hard joints where the board is fixed to the wooden studs on either side though.

If your walls are of such construction, and if they aren't packed with some form of padding in between the boards, then I'm pretty sure that most of the sound from the adjacent room is passing through the wall.

You may have seen little transducers or speakers that plug into something like an MP3 player and have a sucker on the transducer end so you can stick them temporarily to a large flat surface like a window, door, wall, table, etc.  The large flat object it is stuck to becomes a vibrating speaker that amplifies the original sound source to give you a very large sound.  You can even get these devices fitted behind rigid waterproof panels used in showers, and they come with a plug in connector for connecting your portable player.

If you have seen this in action you will realise how sound can easily be conducted through large flat walls.

Unfortunately it would mean tearing off the plasterboard on one side of the wall, inserting wadding, and then nailing on new plasterboard sheets again.  The joints  and nail dents then have to be plastered over and the new wall painted.  This would all be out of the question in a rented home, and would be a large and expensive job where the benefits would not be known until finished.

A solid wooden door probably conducts as much sound as a hollow door that contains a honeycomb of rigid cardboard between outside layers of thin plywood, so in my opinion there isn't much sense in replacing bedroom doors with more solid ones.  The double-glazed uPVC doors you linked to earlier are what we have as a standard in the UK for conservatories and porches.  I think all the nonsense about the gap between the glass being filled with inert gas is just hocus pocus.  They normally come as a manufactured single unit comprising two sheets of glass bonded together around the outside edges at a set thickness.  They normally have a partial vacuum between the sheets of glass that helps to prevent sound passing through.  I see no benefit of having inert gas other than to prevent aerobic bacteria or algae from growing between the panes in the event that the sealed edges develop a tiny air leak.  uPVC is softer than wood and tends not to transmit sounds (conducted vibrations) as readily as wooden frames.

Personally I would buy a nicely patterned large rug or carpet the size of the bedroom wall and screw it onto the wall with ornamental screws.  I'm sure it would help a little bit.

Your problem is that people need air to breathe and sound travels through air.  You cannot create a completely airtight bedroom.

Here's an angle that you might like to try and follow up:
sunhuxAuthor Commented:
Thank you sunhux
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