Internal door construction and soundproofing?
Discussion
I've been looking at various door brochures and came across something intriguing. I wanted to reduce the sound transmitted through the door and I automatically assumed that a fire door would provide sound proofing due to the increased mass over other types. Apparently it's not so clear cut.
I was looking through the Howdens door brochure and noticed that some fire doors were rated as 'sound reducing' whereas some weren't. No other manufacturers or brochures mentioned anything about sound proofing or reduction. Howdens' own website doesn't even mention it.
On specifically looking up the specs of doors that are claimed to be sound reducing, it tells you that it has a decibel reduction of 29. The core material of said doors is flax board. Other fire doors that aren't marked as sound reducing don't have a sound reduction rating, they also have a particle board core.
It's odd that out of all the mainstream manufacturers, only Howdens supplies or differentiates between regular and sound reducing doors. Again, none of this would be evident if I hadn't looked at the brochure first.
Looking further into this, I discovered that flax board has a lower density than particle board but is better at sound reduction. I am however finding conflicting info saying that flax board is denser than particle board.
So... is a flax board core better at sound reduction than a particle board core?
I was looking through the Howdens door brochure and noticed that some fire doors were rated as 'sound reducing' whereas some weren't. No other manufacturers or brochures mentioned anything about sound proofing or reduction. Howdens' own website doesn't even mention it.
On specifically looking up the specs of doors that are claimed to be sound reducing, it tells you that it has a decibel reduction of 29. The core material of said doors is flax board. Other fire doors that aren't marked as sound reducing don't have a sound reduction rating, they also have a particle board core.
It's odd that out of all the mainstream manufacturers, only Howdens supplies or differentiates between regular and sound reducing doors. Again, none of this would be evident if I hadn't looked at the brochure first.
Looking further into this, I discovered that flax board has a lower density than particle board but is better at sound reduction. I am however finding conflicting info saying that flax board is denser than particle board.
So... is a flax board core better at sound reduction than a particle board core?
rinseout said:
I wanted to reduce the sound transmitted through the door and I automatically assumed that a fire door would provide sound proofing due to the increased mass over other types. Apparently it's not so clear cut.
Being pedantic, is that what you really want? I’ve been looking at reducing sound transmission between rooms and it seems like proper sealing/fitting is at least as important as the door slab. Some of the EU based manufacturers make a very big thing of it being a complete system. LooneyTunes said:
Being pedantic, is that what you really want? I’ve been looking at reducing sound transmission between rooms and it seems like proper sealing/fitting is at least as important as the door slab. Some of the EU based manufacturers make a very big thing of it being a complete system.
I've currently got hollow doors. I'm quite certain that swapping these for doors with solid cores will make a drastic improvement.I agree that a system should be fitted, which i'm looking into, but I don't want to make it look like an HMO.
I'm curious as to why a door with a one type of solid core is deemed an acoustic product, and a different type of solid core is not. There may be no difference, but one has a dB rating whereas the other has no rating.
rinseout said:
LooneyTunes said:
Being pedantic, is that what you really want? I’ve been looking at reducing sound transmission between rooms and it seems like proper sealing/fitting is at least as important as the door slab. Some of the EU based manufacturers make a very big thing of it being a complete system.
I've currently got hollow doors. I'm quite certain that swapping these for doors with solid cores will make a drastic improvement.I agree that a system should be fitted, which i'm looking into, but I don't want to make it look like an HMO.
I'm curious as to why a door with a one type of solid core is deemed an acoustic product, and a different type of solid core is not. There may be no difference, but one has a dB rating whereas the other has no rating.
It’s more about the seals
But also - companies such as howdens can’t advertise a door as acoustic rated unless it’s got acoustic certification by the door core manufacturer
It doesn’t mean that door is any more acoustically sound than the one next to it without acoustic certification
Generally the certification will state that the 29db acoustic rating applies when using specific seals - bat wings along the edges and top and ideally a drop seal to the base
If you go to a website called Norseal you can fine out what seals are required for certain dB ratings against different core materials
But also - companies such as howdens can’t advertise a door as acoustic rated unless it’s got acoustic certification by the door core manufacturer
It doesn’t mean that door is any more acoustically sound than the one next to it without acoustic certification
Generally the certification will state that the 29db acoustic rating applies when using specific seals - bat wings along the edges and top and ideally a drop seal to the base
If you go to a website called Norseal you can fine out what seals are required for certain dB ratings against different core materials
Yes, as I mentioned on your other thread a fire door is overkill. You will have to ring the manufacturer if you want all the technical details of different construction methods and materials. As others have mentioned, and even though you don’t want to listen, gaps around the sides and more so at the bottom will always allow noise through. It’s hard enough to soundproof a wall, never mind an internal door.
If you want a soundproof door buy a soundproof door set, the core is part of it but so are all the seals and the way the door fits in the frame and the frame itself and how that's sealed and mounted. And given the way the seals usually work especially at the bottom you want that supplied instead of trying to fit them later.
On a basic level a solid higher mass door like a fire door offers better sound deadening than a simple hollow one, but a solid wood core isn't necessarily the best option. You want to deflect, diffuse and absorb the energy which is why rubber and bitumen and mass loaded vinyl and melamine foams and all those other materials are used in sound reduction. So something like a flax core, being a bit flexible and more porous might work slightly better than wood.
On a basic level a solid higher mass door like a fire door offers better sound deadening than a simple hollow one, but a solid wood core isn't necessarily the best option. You want to deflect, diffuse and absorb the energy which is why rubber and bitumen and mass loaded vinyl and melamine foams and all those other materials are used in sound reduction. So something like a flax core, being a bit flexible and more porous might work slightly better than wood.
Actual said:
We have 18 internal doors and I know because I'm just pricing up to replace them all.
Almost a waste of time because apart from the airing cupboard and a few cupboards we hardly ever close our internal doors.
We close doors when we don't want to listen to the same stuff.Almost a waste of time because apart from the airing cupboard and a few cupboards we hardly ever close our internal doors.
By closing two firedoors, we can achieve plenty of attenuation.
One can be listening to classical music or rock, while the other is watching TV with dialogue you have to listen to.
One door closed is enough to seriously reduce the sound of the extractor fan in the kitchen, or to have a phone call while other things are going on.
Our walls are maybe more acoustically isolating than some, the internal block walls are dry-lined.
This house is noticeably more soundproof than the one I grew up in, with flat ply doors.
It's not something that worries me much, just something I've noticed.
A draught seal probably damps the motion of the door panel more significantly than it stops sound waves going through the gap?
A plywood door is like a big diaphragm or speaker cone?
Sound is like water, you can have the thickest door (or a door made from rubber) but if the surrounding areas aren't sealed tight you'd be as well as not bothering.
You'll be better with a thin less dense door and very good seals around it and the frame, than you will with a 54mm thick dense door and nothing done around it.
You'll be better with a thin less dense door and very good seals around it and the frame, than you will with a 54mm thick dense door and nothing done around it.
Little Lofty said:
As others have mentioned, and even though you don’t want to listen, gaps around the sides and more so at the bottom will always allow noise through.
Where are you getting this from? Can you quote the text where I have refuted this?People seem to be able to extrapolate a lot of information from seemingly nothing. How? I asked about the difference between two cores, yet some are intent on giving advice about filling in the mariana trench.
FWIW, our doors, with hard floors and gaps under doors, still attenuate sound a great deal.
If you want the nth degree of soundproofing, you will need to consider sound transmission via floors and other structure of the house.
It helps to be clear what you're aiming for.
Personally I think fairly loud TV and music in one room not being annoying in the next room is a reasonable aim.
That may be more or less dB for different people.
It's also good not to be woken by the washing machine when it comes on at 5AM, closing the utility room door does that.
If you want the nth degree of soundproofing, you will need to consider sound transmission via floors and other structure of the house.
It helps to be clear what you're aiming for.
Personally I think fairly loud TV and music in one room not being annoying in the next room is a reasonable aim.
That may be more or less dB for different people.
It's also good not to be woken by the washing machine when it comes on at 5AM, closing the utility room door does that.
rinseout said:
Little Lofty said:
As others have mentioned, and even though you don’t want to listen, gaps around the sides and more so at the bottom will always allow noise through.
Where are you getting this from? Can you quote the text where I have refuted this?People seem to be able to extrapolate a lot of information from seemingly nothing. How? I asked about the difference between two cores, yet some are intent on giving advice about filling in the mariana trench.
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