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Soundproofing Forum Topics => Soundproofing Windows and Doors => Topic started by: goblinsly on March 12, 2012, 02:15:37 AM

Title: Simple door insulation
Post by: goblinsly on March 12, 2012, 02:15:37 AM
Hey everyone,

This is my first post on this wonderfull board soo first of all, nice to meet you all. :)

Soo here is my question. There is a door in my apartment that used to be badly atached soo it had a big gap. This meant heat was leaving the place and noise was coming in. I reattached them and also used some insulating tape soo its great now. The only noise i want to block is noise from chating and occasionaly jelling, maybe a dog bark here and there ( its not much of a problem really ). Soo i ordered tervol dp-8, its basicly rock wool and i think its one of the best if not best price/performance material i can get in my country. Its dp-8 meaning its very dense. Since i dont know whether i will be staying in this place 1 month, 1 year or 5 years and when i leave i cant pick up the door and take them with me, i will try to make this simple.

The plan is to cut wool into correct size and shape and glue it together soo it will be the same dimension as the door. Then i will wrap polyvinyl around it ( make it air tight ) to prevent wool partacles to fly around my apartment. Then i will simply use something like 2 sized sellotape to "glue" it to the doors.

You probably think that this is a very bad idea and i agree with you but since i am on a tight budget and i have all the things at home exept for rock wool which wont cost much, i think its the best idea. I dont need a perfect solution since i am not building a studio or trying to prevent drum noise to come in or go out, i am just trying to get a little improvement and since my door is very thin, i think it should help at least a little.

I will be happy for some feedback on my idea. Buying new door or something like that is out of the question sadly.
Title: Re: Simple door insulation
Post by: whatismisophonia on March 12, 2012, 03:05:10 AM
Insulation material is marketed as a soundproofer because companies can sell more of it that way.  Im sure it will help a little, but I think what might be better is 2 pieces of any cheap, somewhat thick, solid material glued together with sound damping glue and attached to the door.  I didn't recommend a MLV door cover because it seems to be out of your price range.
Title: Re: Simple door insulation
Post by: Randy S on March 13, 2012, 04:37:14 PM
You want cheap, attach some cement board to the door, hardie might be able to find that in your area.
And make sure you seal the door completely!

You need MASS not absorption.....
Title: Re: Simple door insulation
Post by: goblinsly on March 15, 2012, 05:39:28 PM
Well since i already ordered rock wool, how about that. A thin layer of rockwool and then something massive over it to cover it. Cement board ? That isnt gypsum board is it ? Its prolly something very heavy. Have to be carefull about the weight thought, soo i dont pull out the doors.
Title: Re: Simple door insulation
Post by: Randy S on March 15, 2012, 05:49:38 PM
make sure door has 3 hinges... put Mass on before Rockwool....yes cement board is slightly heavier than drywall. It is used under tile sometimes.
Title: Re: Simple door insulation
Post by: whatismisophonia on March 15, 2012, 06:47:22 PM
I have 1/2 inch hardibacker attached to my bedroom door; originally, my door was really cheap and thin.  The hardibacker needs to be cut with a smooth diamond cutting blade, and will make alot of dust.  The 1/4 inch hardibacker can supposedly be scoored with a utility blade, and snapped; upward, toward the score, not down away from it like concrete durock sheets, which are solid concrete wrapped in fiberglass mesh.  The hardibacker has wood fibers mixed in with it, so that it becomes a composite material.  With durock, you simply cut through the fiber mesh and snap it like sheetrock, then cut through the mesh on the other side (this can create a farely uneven break though, diamond saw is more exact).  One final note is that both types may be too small for your door, as they come in 3x5 foot sheets.  This was the case for my door, and I used the left overs from another sheet that I had gotten to use for a window plug to finish the door. 
Title: Re: Simple door insulation
Post by: goblinsly on March 26, 2012, 12:23:26 PM
Tnx for all the replies. Like i said, since i already got rockwool, i will use it + use some other material aswell. But i need to verify something first. Rockwool comes cut in pieces ( i think like 1000 x 600 centimeters ). Its supposed to be very dense, which means its structure is kindof like gypsium board ( its quite hard, can stand on its own, etc. ). But a problem is you cant just put it on wall and leave it like this. You have to put something over it otherwise you will have home full of wool dust.

Since i am looking for a cheap solution and also solution that will allow me to move rock wool to another place when i move, i came up with a simple solution like i mentioned:

I plan to put wool pieces together until i get the shape and dimensions of the door. Then i will use something like selotape to tape the boards together and then wrap polyvinyl tightly around it ( make it air tight ) to make 1 big plate ( door dimension ). This thing can then easily be attached to doors and also be removed. Polyvinyl should prevent dust from escaping. It will look ugly but i can always tape something over it wallpaper or something. I hope that condensation wont be a problem since polyvinyl will be airtight.
Title: Re: Simple door insulation
Post by: whatismisophonia on March 26, 2012, 11:30:40 PM
you got a website or something where we can see what product youre talking about?  I've seen rockwool as a thin stiff acoustic panel, but from your description, your products seems more like a type of soundboard.  If that's the case, I'm sure it will be more effective than an acoustic panel at actually blocking the sound.  Try it, sure; if it doesn't work as well as you'd like, layer it with something stiffer and denser.
Title: Re: Simple door insulation
Post by: goblinsly on March 27, 2012, 02:25:54 PM
Its actualy called stone wool, i dont know why i thought its called rock wool. Anyway i found this catalogue:

If you go to page 9 you will find it. If i go to their page and click my country it actualy says that this material is used for thermal and audio insulation of walls. But on the link i gave you its actualy under door insulation which is kind of funny since i am doing door insulation and i was kind of worried if this material will be ok for doors. Well, it seems it is best used for doors hehe.

You have some characteristics about it on the link. I used the same material for insulating before but it was a lot less dense. This boards i got are very dense ( tervol DP-8 ). The material i used before wasnt. It could be squized like 1000% or more. This boards cant be. Soo i think it should be better then nothing. And it was really cheap. But for other purpuses i would be glad if i could find a material that is about 2 cm thick, cheap and offers some insulation ( since my walls dont need much insulation ). And more importaintly, i want them to be ready to put on the wall right out of the box. Cause this stone wool, i will have to put polyvinyl over it ( otherwise i will have wool parts all over my place ). And its extra work for me.
Title: Re: Simple door insulation
Post by: Randy S on March 27, 2012, 03:35:44 PM
Your in fine shape, just remember mass on the door first than this product as the absorption.
Title: Re: Simple door insulation
Post by: goblinsly on March 27, 2012, 07:06:00 PM
I might have to put mass on the other side of the door. Its the same though, doesnt matter whether wooden door - mass - absorption or mass - wooden door - absorption. Its the same, right ?

Anyway i just finished puting the wool on. It was a mess. A few times i almoast lost my nerves and threw it all out the window. Like always, i didnt measure enough. Since im studying compter science i seriously have to learn to measure, be precice and be patient. Anyway i put the wool into polyvinyl and taped it to the door. When i say it i make it sound soo easy, but infact i dont remember ever doing something as absurd and annoying. I did it this way to save time but infact i would have done it 3 times faster if i used the method i describe in a few lines. Since i wasnt precise i left gaps on basicly all sides. But its already much better, the material isnt half bad for the price.

But here comes what i will do next:

I will get me some wood and attach it to the sides, top and bottom of the door. Like this:

Basicly i will make a simple frame, put it on the door and squize wool in. Then i will put a layer of wood over it to seal it. This way i can make sure its closed as it should be, with no gaps ( and if there is a minimum gap i can always use insulation tape, as long as its 2 mm and not 10 mm like now ). But for now, i am happy and i am still left with like 8 m^2 of material. Oh, i apologise for my bad english and amateur questions, it must sound stupid to those of you who are pros at sound insulation. But when your knowledge about it is limited and your wallet half empty, this is the best way to go. Thanks for all the help soo far and keep those advices coming. :)
Title: Re: Simple door insulation
Post by: goblinsly on March 30, 2012, 06:43:34 PM
A little update. Today while studying relational algebra, indexing and other, quite boring computer science stuff, i got 2 ideas which bothered me soo much i had to lay the book aside to write here !

First thing that got my attention is a memory. A memory of when i put my bed mattress into polyvinyl bag ( do not ask why ), but a tiny hole in it, stuck a vacuum cleaner to it and pressed on. What happened was that bed matress quickly shrinked to about 1/10 of its size, and the matress itself was quite hard at the time, with hands it was impossible to shrink it even to 1/2 of its size. Soo lets say that 1 happy guy, lets call him me, would do the same thing with stone wool. One would acomplish many things doing this. First, it would become more dense. Second it would be thinner, therefor either a) take less space -> be usefull for places where u have very little place for insulation or b) u can put more of it there, for instance 3 layers would take as much space as 1 layer before. Soo 3x better insulation with no extra space. Might be usefull for some of my computer modding projects aswell, i am sure it would be much better at insulating computer fan&disk noice then foam and stuff like that.

And second. I remember many of you guys said that beside stone wool ( which absorbs ), i need masive material aswell. Soo i was thinking. Since most of my classes at my college are basicly pure math, i use a lot of paper. And i mean, a lot. Not enough to make any money by selling it but enough to make some objects out of it. Since i remember that paper is quite heavy, strangely heavier then any other piece of wood of the same size i ever seen, would there be any use for paper as mass material ? For instance tightly glued together with maybe some foam between it ? Sadly paper is tight already soo i wouldnt get any extra space by using the vacuum on it but still, for once, as much as i hate this eco-fanatism, i could say i am actualy environment friendly and recycling ?

Just a thought, probably quite stupid but still, just a thought. :)
Title: Re: Simple door insulation
Post by: Randy S on March 30, 2012, 06:55:20 PM
Paper will not have to at least double the weight of the door to achieve a 6 db drop....
Mass Law....

vacuum idea is basically increasing the density value which in turn absorbs at lower frequencies.
Title: Re: Simple door insulation
Post by: goblinsly on March 30, 2012, 11:16:05 PM
Absorbs at lower that good or bad ?
Title: Re: Simple door insulation
Post by: Randy S on March 31, 2012, 02:53:30 PM
its a good thing...just remember your greatest reductions come from mass...
Title: Re: Simple door insulation
Post by: whatismisophonia on April 01, 2012, 04:11:48 AM
Interesting thing about a vacuum is that no sound can travel through a complete vacuum; however you'd need much more of a vacuum than you could place on a plastic bag for any effect I'm thinking.  But anyway, by shrinking down your material, all you are doing is compressing it to make it more like a solid material, which will allow it to BLOCK more than ABSORB.  But then, that's what you want with solid materials anyway.  To absorb better at low frequencies, you typically need thicker foam to absorb more of the long low frequency wavelength, as per my understanding.  Again, if blocking is what you want, just forget about the wool and do sheetrock or something (if you get a pin prick in your plastic, your vacuum is screwed).
Title: Re: Simple door insulation
Post by: goblinsly on April 01, 2012, 04:55:37 PM
But what is mass really ? I have 2 walls near my bed that are from brick. Single brick wall but still, its mass. And it is worth sh*t, it makes me soo mad. It just isnt normal to be able to hear neighbours talking, pluging things into electric dose, opening drawers, etc. Not to mention hoses and things, its even worse. Sometimes i can even hear what kind of job ppl did at their bathroom ( whether it was pee or.... ), and i am talking about next door neighbours, not neighbours on top or below me. I just dont know how ppl building houses can be soo insensitive about this, and this part of house is 12 years old, soo its pretty new.

As for the wool, the idea wasnt to create vacuum permanently, the idea was just to suck all the air out to shrink the wool to about 1/3 of space, which i think could be done and then i would use strong duck tape to shrink it permanently ( even if the vacuum would get screwed, the duck tape would hold the wool together. Or maybe i can get some steel tiny plates to hold it together ). Therefor i could put 3x the amount of wool and it would take as much space as single layer. The idea wasnt to make it more dense to be mass instead of absorbant.

Btw this walls i was telling u about, already containing mass. Adding wool to it would be good, right ? But the problem is, i could only afford wool that is max 1 cm thick ( 0.4 inches ) or at some parts 2 cm ( 0.78 inches ), otherwise i lose too much space which i need at that part. Is it going to make any difference at all ?
Title: Re: Simple door insulation
Post by: goblinsly on July 11, 2012, 12:49:31 AM
Just a bit of an update.
My doors are insulated with rock wool which is encased in polyvinyl to prevent any trouble with breathing, and all of that is also covered with wood and tightly shut. If there is an interest i can post a picture or two. Doors are quite heavy soo i have seen some bending but i fix it regulary. There is still a slight problem with gaps but now that i finaly got some time i am trying to fix all of them. But the difference between this and previous situation is huge. You basicly cant hear tv and music anymore, sadly human voice is still heard and i have to be honest, i simply hate human voice, it is driving me nuts that when i am studying for my computer college exams that i hear other ppl, it makes my skin crawl. But i think there is something in the voice that makes it impossible to complete shut off. I even hear talking from my neighbours and there is a brick wall between wonder i can hear speech through wooden doors with rock wool and walls made of 2 pieces of gypsum board and some thin and extremely non dense glass wool ( for comparison, my DP8 rockwool is soo dense that you can walk on it and it wont change its shape, this glasswool is such that you can squize it from 5 cm to 1 mm with no efford ).

Title: Re: Simple door insulation
Post by: goblinsly on July 23, 2012, 05:20:54 PM
I replaced the glass wool inside my walls with rock wool. I think as far as absorbtion goes this is all i can do for now. I have about 2 cm of space i could use for mass. Do you think it would make a difference ? I am looking for something cheap and effective to act as a mass, maybe some cement boards ? It wont cost much since i only need to insulate about 5 square meters, soo what do you suggest ?
Also i was wondering....tiles, ceramic tiles we see in kitchen, bathroom....they certanly weight a lot. Is this effective as a mass material ? They dont cost much and i am pretty sure i could get as much as i need for free. I am just thinking out loud here, as a student every cent saved is welcome, and if tiles can do the trick....great !
Title: Re: Simple door insulation
Post by: Randy S on July 24, 2012, 03:46:30 PM
Use the cement board, it has a good mass value and is cheap.

Title: Re: Simple door insulation
Post by: goblinsly on July 24, 2012, 07:56:54 PM
Thank you soo much for your answer !

Just to verify that we are talking about the same thing:

It says it has good sound proff quality. But when i see what it is made of...63% chipboard, 25% cement, 10% water...did i find the right thing ? Because if chipboard is supposed to give good insulation...i have chipboard in cellar and i could use them....but i dont think they are the best thing to use, maybe that 25% cement makes all the difference ?

Also i was thinking, since now i have gypsium board. Maybe i should put 1mm foam over it and put cement board over it ? Maybe this foam would prevent or remove some of the vibrations ? or maybe Green glue ? This way i would have mass, absorbtion and damping. looking at this guide:
Title: Re: Simple door insulation
Post by: Randy S on July 24, 2012, 09:19:47 PM
your looking for cheap and heavy...density is mass... so yes cement is good.

what your missing is there attempt of decoupling by the use of staggered studs...

I use the cement board/ green glue / drywall system in a lot of my projects. It works well especially when it is decoupled from the structure...
Title: Re: Simple door insulation
Post by: goblinsly on July 24, 2012, 10:42:05 PM
I know cement is good but in those cement boards there is only 25% cement....i guess board from 100% cement would be better. But would probably cost a lot more...soo this will be fine, some wood, some cement...

I am quite limited in what i can do here since i dont own the place. The wall is like i said. A frame from aluminium or steel, a drywall on each side and rockwool in between. Now i have about 2 cm for cement board. Soo the best i could do is make a tiny space between cement board and drywall. Since i have only 2 cm of space....i guess if i buy 1 cm cement board and leave 1 cm of space between drywool and cement board and basicly use something like foam part every meter or soo to keep that 1 cm distance. That way i can prevent vibrations moving from drywool to cement board. I will do this on 1 side and i might, i stress i might be able to do the same on the other side....that way its mass followed by absorbtion no matter where the noice is coming from.
Title: Re: Simple door insulation
Post by: Randy S on July 24, 2012, 11:11:14 PM
There is no doubt that treating both sides will be a great improvement...based on the frequency your trying to reduce...human speech..perfect...but for low bass and structural impact your not going to get a decent reduction with out braking the direct path..

Im not saying your not going to get any reduction just not as good as we are used to experiencing.
Title: Re: Simple door insulation
Post by: goblinsly on July 25, 2012, 01:00:51 AM
Like i said, human speech is all i care about right now. Soo since i am limited in space....what do you suggest ? Put cement board directly on drywall or put green glue between, or maybe some spacers soo there would be a gap between drywall and cement board ( those spacers would be from material that doesnt allow much vibrations ).
Title: Re: Simple door insulation
Post by: Randy S on July 25, 2012, 03:00:21 PM
cement board then green glue then drywall.. make the gaps..

If you create a gap it must be filled with an can not be left empty....
Title: Re: Simple door insulation
Post by: goblinsly on July 25, 2012, 08:24:13 PM
And making another gap wouldnt make sense since there is already wall ( 2 pieces of drywall and stonewall between them ). Btw i read some tests of different setups and this greenglue seems to make a big difference. Considering how little space it takes, almoast nothing....difference is huge. But basicly it works the same way as if i put some foam between ? I will use greenglue offcourse because it is better but basicly the idea is the same, damping of vibrations ? Greenglue converts mechanical energy to heat, not sure if foam will do that though.

If possibly i will also put cement board on other side. Soo it will be like this: Cement board, greenglue, drywall, rockwool, drywall, greenglue and cement board. I hope that will remove as much speech as possible. Btw i am wondering...why do this cement boards have only 25% cement ? Why not like 80% cement ? Because of the cost or ? Soo even if its 63% wood and 20% cement, this cement board will be OK ? Or should i go for more costly, osb ?
Title: Re: Simple door insulation
Post by: goblinsly on August 24, 2012, 08:48:13 PM
Just a little update.

I figured out that basicly all the noise is coming through the gap between the doors, the walls are insulating pretty darn well i must say ! Since i made this door and insulation for them, its impossible to get a tight gap near the door handle when you close them ( theywont close because of the thickness of insulation ). Soo what i will do is extend some cement board or gypsium board soo that when the doors close, this board will cover the hole. It should work well.
Title: Re: Simple door insulation
Post by: Randy S on August 24, 2012, 08:55:54 PM
great job, when you do the overlap make sure you use some closed cell foam or something to make a good seal when in the closed position.

Title: Re: Simple door insulation
Post by: goblinsly on August 27, 2012, 12:34:45 AM
I will, i just have to go to some shops and find something good ( they usualy sell things for thermal not audio insulation ). Right now i am using some styrodur + foam from an old chair since that is the only thing i had handy and i couldnt leave such a huge gap. If i exchange that with gypsium board and some good foam ( foam actualy made for sound insulation not sitting on ), it should be much better, at least i think.

If i am honest i like gypsium board more then cement board. Cement board has greater mass but gypsium board is soo easy to work with....its like cuting styrodur or even better.....and since fixing those holes and gaps around doors will demand lots and lots of small pieces, gypsium is just great for this. Cement can only be cut by jigsaw i guess, unlike gypsium that can be cut by stanley knife. The only thing that bothers me is the price. 1 cm of gypsium board costs as much as 5cm of pretty dense rock wool.

Btw since i am here...i insulated basicly all of the wall. But there was about 50x50cm ( about 20x20 inches ) part of wall with wires and such, therefor i was unable to replace the existing fiberglass wool ( very thin and not dense ). I was thinking, since i already did this before and its quite simple... i can drill a  hole or two and pour polyuretan foam inside to fill it since the space is more or less empty, with just those wires and fiberglass wool that is like 2cm. Would that be ok ? Polyuretan is not as good as rockwool of DP8 density but still it is better then 8cm of empty space?
Title: Re: Simple door insulation
Post by: goblinsly on August 29, 2012, 12:03:18 AM
Oh and an extra question...if i decide to add a layer of gypsum board to the door ( once i finish strengthening them ) there a big difference whether i screw them directly to the door or if i use the same number of screws but leave some really minimum gap between gypsium board and doors ? Would that gap be enough to reduce the sound further since there would be no direct contact and sound would have to change the frequency it travels through ( wood - air - gypsium is harder to travel then wood and gypsium ). Or maybe greenglue would be even better ? I am not even sure, does greenglue work as a normal glue soo you dont have to use screws, or is it just like silicone you use in the kitchen ? Not even sure i can buy greenglue in my country, but it sure would be nice, its very cheap and if the reviews are to be belived, it is a mirracle !
Title: Re: Simple door insulation
Post by: whatismisophonia on August 31, 2012, 02:57:36 AM

I originally posted this pdf here:,3463.0.html

p.s.  I recommend that you get a 15 buck box fan and turn it up to 'high'; your cheapest noise solution.  Also, if you attach with greenglue, you gotta screw it.  You might also look into 'quietglue pro'.  Most people use Greenglue anyway because it's been out longer and isn't so questionable as to whether it gives good results, though GG does requre a longer drying period. Wherever it is that you live, you should be able to get one of those two at least.
Title: Re: Simple door insulation
Post by: goblinsly on September 15, 2012, 11:30:43 PM
Thx for your reply,

I dont need a fan on high speed....i already have a fridge 3 meters away from my bed and in the next days i will insulate it to make it quiet cause it bothers me a lot when i try to sleep or study ( using some neat things like 4 120mm fans ) and also make it more efficient, should be fun.

The doors are doing a great job considering the cost, i just need to fill those gaps because it is known that no mater how well you insulate, if you need gaps like wont work. I have all the material soo in the next days i will do the job and let you know how it went ! I also bought a little wheel to attack to the door since they are very heavy now and constantly bend a little and then drag on the floor. I cant be bothered with an extra or stronger hinge right now soo this should be OK heh.