I thought I'd float this one for others to think about.
A brilliant building material, way better than any traditional stuff. Not that new actually as it was invented by a Swedish architect (huge surprise that for me as a builder) in 1924.
This product is made by an extrusion process and I always wondered why manufacturers did'nt experiment more with different profiles.
What is it - a lightweight cellular material, each block having millions of air cavities, hence it's light weight, superb insulation and for us acoustic properties.
The best of the bunch is made by a German company, check out - Xella - Baustoffe, Trockenbau-Systeme und Kalk - Xella International GmbH. They have sites in many different languages so that is no problem.
It is easy to work and shape if you want and is bonded by a super strength white adhesive type of mortar, something like a lime mortar. This is known as the 'thin joint method', anyone can use these with only half a brain.
I have been putting off for many reasons building O/B speakers using my s/hand Grand Heil AMTs with 15" woofers, maybe 2 per side.
I've looked at all the info on baffle material and can see no reason why I should'nt use this cellular material - it has no hard reflective surfaces, is easy to shape and bond, lightweight and now I see that Xella is producing curved blocks., these are of special interest to me.
Indeed you can buy large panels of this material from 5-10cm, so using a single piece for a baffle.
Come to that, it would be very easy to build complete enclosures with curved back sections.
The possibilities are endless and although relatively expensive versus other materials to construct a home with, huge savings on labour costs, to construct speaker baffles/cabinets et al really cheap, no special tools nec.
Check out your particular countries Xella site online and you will see who the retailers are and go take a look - you maybe surprised. No expensive layout on materials if you decide to experiment, since you would'nt need that much material to construct your O/Bs or cabinets.
I shall be building my house of this material including my music room, to include walls and ceiling, floors to be insulated concrete overlayed with battened t&g pine flooring - vamos a ver.
A brilliant building material, way better than any traditional stuff. Not that new actually as it was invented by a Swedish architect (huge surprise that for me as a builder) in 1924.
This product is made by an extrusion process and I always wondered why manufacturers did'nt experiment more with different profiles.
What is it - a lightweight cellular material, each block having millions of air cavities, hence it's light weight, superb insulation and for us acoustic properties.
The best of the bunch is made by a German company, check out - Xella - Baustoffe, Trockenbau-Systeme und Kalk - Xella International GmbH. They have sites in many different languages so that is no problem.
It is easy to work and shape if you want and is bonded by a super strength white adhesive type of mortar, something like a lime mortar. This is known as the 'thin joint method', anyone can use these with only half a brain.
I have been putting off for many reasons building O/B speakers using my s/hand Grand Heil AMTs with 15" woofers, maybe 2 per side.
I've looked at all the info on baffle material and can see no reason why I should'nt use this cellular material - it has no hard reflective surfaces, is easy to shape and bond, lightweight and now I see that Xella is producing curved blocks., these are of special interest to me.
Indeed you can buy large panels of this material from 5-10cm, so using a single piece for a baffle.
Come to that, it would be very easy to build complete enclosures with curved back sections.
The possibilities are endless and although relatively expensive versus other materials to construct a home with, huge savings on labour costs, to construct speaker baffles/cabinets et al really cheap, no special tools nec.
Check out your particular countries Xella site online and you will see who the retailers are and go take a look - you maybe surprised. No expensive layout on materials if you decide to experiment, since you would'nt need that much material to construct your O/Bs or cabinets.
I shall be building my house of this material including my music room, to include walls and ceiling, floors to be insulated concrete overlayed with battened t&g pine flooring - vamos a ver.
Hi,
You are talking about aerated concrete panels like Poroton and Multipor?
You can buy those quite cheap in nearly every DIY market in Germany.
You can shape that stuff easily with a saw, a rasp or a drill.
It´s a lot lighter than cast concrete but also less strong and stiff.
Thinner boards break easily.
You may need a supporting structure.
You prababely also need to seal the surfaces as small parts come off (grain of sand and alike)
jauu
Calvin
You are talking about aerated concrete panels like Poroton and Multipor?
You can buy those quite cheap in nearly every DIY market in Germany.
You can shape that stuff easily with a saw, a rasp or a drill.
It´s a lot lighter than cast concrete but also less strong and stiff.
Thinner boards break easily.
You may need a supporting structure.
You prababely also need to seal the surfaces as small parts come off (grain of sand and alike)
jauu
Calvin
No,
I'm talking about Thermoblock 8 in Germany/Austria & Switzerland and Thermopierre in France, same product, different name. Internal walls are made of 7cm panels and they don't crumble and fall down. BTW you can build earthquake proof houses from this material. I shall be using aercrete roofing panels for my house - over 5 metres in length, which have only 6mm re-inforcing steel.
Also it's just as rigid as dense concrete or you could'nt build houses from it could you? and yes it is 3 times lighter than dense concrete.
You can buy inferior copies of it nearly everywhere - Celcon in Denmark/UK and they do crumble quite easily. You can even buy some Xella products in DIY stores like Brico Depot or Leroy Martin in France but nothing like the full range.
You need to visit an official supplier and get hold of a catalogue to see the full range.
When finishing whatever shape you want to acheive, the surface can be 'fixed' with a 5 - 1 Unibond wash or painted, indeed any kind of finish you want.
If I were you I would concentrate on understanding the properties of this material which are pertinent to speaker building.
To be able to easily remove sharp external corners on baffles, to use curved inner surfaces, on all sides if you want and of course no hard reflexive surfaces.
I'm talking about Thermoblock 8 in Germany/Austria & Switzerland and Thermopierre in France, same product, different name. Internal walls are made of 7cm panels and they don't crumble and fall down. BTW you can build earthquake proof houses from this material. I shall be using aercrete roofing panels for my house - over 5 metres in length, which have only 6mm re-inforcing steel.
Also it's just as rigid as dense concrete or you could'nt build houses from it could you? and yes it is 3 times lighter than dense concrete.
You can buy inferior copies of it nearly everywhere - Celcon in Denmark/UK and they do crumble quite easily. You can even buy some Xella products in DIY stores like Brico Depot or Leroy Martin in France but nothing like the full range.
You need to visit an official supplier and get hold of a catalogue to see the full range.
When finishing whatever shape you want to acheive, the surface can be 'fixed' with a 5 - 1 Unibond wash or painted, indeed any kind of finish you want.
If I were you I would concentrate on understanding the properties of this material which are pertinent to speaker building.
To be able to easily remove sharp external corners on baffles, to use curved inner surfaces, on all sides if you want and of course no hard reflexive surfaces.
Hi,
do YOu have a link or a DS?
On Xellas website the search doesn´t get a result for Thermoblock or Thermopierre.
Google search results in links to Ytong, Poroton, Multipor etc. those aerated cretes that are not practical to use for Audio.
jauu
Calvin
do YOu have a link or a DS?
On Xellas website the search doesn´t get a result for Thermoblock or Thermopierre.
Google search results in links to Ytong, Poroton, Multipor etc. those aerated cretes that are not practical to use for Audio.
jauu
Calvin
Calvin,
I don't know where your looking but I found no problem at all in finding the Swiss
Xella site at all and it definately shows the Thermablock 8 type.
If you have no experience with this material how do you know it is not suitable for the purposes I have outlined?
You need to have a look at the online catalogue to see the specs and you actually have to find a retailer where you can actually handle the material itself.
otherwise tour opinion is worthless.
I don't know where your looking but I found no problem at all in finding the Swiss
Xella site at all and it definately shows the Thermablock 8 type.
If you have no experience with this material how do you know it is not suitable for the purposes I have outlined?
You need to have a look at the online catalogue to see the specs and you actually have to find a retailer where you can actually handle the material itself.
otherwise tour opinion is worthless.
Hi,
the link from #1 leads to Xella.com, where there is search mask.
Neither Thermoblock nor Thermopierre returns a hit.
Under Xella.ch and Xella.fr there's even no search mask.
The only pic looking like a block is the Ytong block.
So, again no hit.
There is also no download section at all on all three sites, .com .ch or .fr.
Could You supply for a direct link?
jauu
Calvin
ps. eventually found it on the Ytong website under Thermobloc 08 (without k)
the link from #1 leads to Xella.com, where there is search mask.
Neither Thermoblock nor Thermopierre returns a hit.
Under Xella.ch and Xella.fr there's even no search mask.
The only pic looking like a block is the Ytong block.
So, again no hit.
There is also no download section at all on all three sites, .com .ch or .fr.
Could You supply for a direct link?
jauu
Calvin
ps. eventually found it on the Ytong website under Thermobloc 08 (without k)
No.
The stiffness is roughly proportional to the density.
The Civils lab were testing various porous and other lightweight concretes while I was at University 1970, or 1971. They clearly showed both strength and stiffness dropped like as stone as density reduced.
Thermalite was one tradename used in the UK.
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Calvin,
just google ytong and choose the preisliste one. This will take you to the full product range with all their respective specs usefully in German for you.
All aercrete blocks are used to build houses Andrew - what makes you think that you can't build OB baffles or enclosures with them and you hav'nt touched on their acoustic properties.
Your looking at them from a construction point of view, you appear to be a civil engineer, now you need to use that knowledge to look at them from a speaker or even an equipment angle.
Have you ever been inside a house constructed from aercrete blocks. If you did the first thing that would strike you is the lack of ringing or reverberation. I live in France and they use 7/8 cm cavity clay blocks for most if not all internal walls and the houses ring like a bell. Or to comply with the latest regs using metal studding filled with rock wool and finished with only one skin of plasterboard sucks the life out of music.
This material is now being used to construct sound studios and I am not surprised.
Calvin said that they are cheap - not relative to other wall building materials but yes they are way cheaper than using marine ply which then has to be veneered.
Some choose to use solid wood cabinets, not clever that unless you want to destroy any neutrality because real woods are great for making acoustic instruments that deliberately introduce colour into the sound, think Strad.
If you use the recommended mortar which is really an adhesive and made up like a lime mortar which is called Preocol, when it sets if you hit the construction with a sledgehammer it is the block which will break not the bond. I see on the German site that they also make an adhesive, I can't comment on that as I have never used it.
The curved panels 30-60 degrees available (I would imagine to special order) carry the name Caropro in France. Caropro is also available as large panels 240 - 300 x 60 x 10cm, these panels would be ideal to make OBs from. Supporting side panels could be made from the same - to any shape you like.
Supporting big heavy woofers would of course need to be clamped via the back naturally, I personally would think about using bitumen felt as gaskets, pretty not but very effective.
It is the availability of curved panels that I find very interesting, either used as sound re-inforcement behind OBs or similar and as back walls for enclosures. How would that effect filling for enclosures - lots of experiments there, remeber no hard reflective surfaces.
I would think that an effective base of any construction would be pieces of marine ply or MDF of a good thickness to enable castors to be fitted so precise placement would be easy for best sound. It may not be nec. to retrofit spikes like my favourite Norwegian Soundcare spikes.
Ytong/Xella now provide many different finishes for this material, you can in fact paper direct onto to this.
MDF is not ideal for speaker enclosures and was only adopted because HDF - high density chipboard blunted cutting equipment quickly ie. it hurt profits. Both MDF and Marine ply are heavy materials, does this benefit sound reproduction?
This material is worthy of investigation for not so much money, it has excellent acoustic properties, can be shaped into virtually any shape you like and the curved panels really do warrant empirical research.
However if you take entrenched attitudes with you then maybe better not to bother.
just google ytong and choose the preisliste one. This will take you to the full product range with all their respective specs usefully in German for you.
All aercrete blocks are used to build houses Andrew - what makes you think that you can't build OB baffles or enclosures with them and you hav'nt touched on their acoustic properties.
Your looking at them from a construction point of view, you appear to be a civil engineer, now you need to use that knowledge to look at them from a speaker or even an equipment angle.
Have you ever been inside a house constructed from aercrete blocks. If you did the first thing that would strike you is the lack of ringing or reverberation. I live in France and they use 7/8 cm cavity clay blocks for most if not all internal walls and the houses ring like a bell. Or to comply with the latest regs using metal studding filled with rock wool and finished with only one skin of plasterboard sucks the life out of music.
This material is now being used to construct sound studios and I am not surprised.
Calvin said that they are cheap - not relative to other wall building materials but yes they are way cheaper than using marine ply which then has to be veneered.
Some choose to use solid wood cabinets, not clever that unless you want to destroy any neutrality because real woods are great for making acoustic instruments that deliberately introduce colour into the sound, think Strad.
If you use the recommended mortar which is really an adhesive and made up like a lime mortar which is called Preocol, when it sets if you hit the construction with a sledgehammer it is the block which will break not the bond. I see on the German site that they also make an adhesive, I can't comment on that as I have never used it.
The curved panels 30-60 degrees available (I would imagine to special order) carry the name Caropro in France. Caropro is also available as large panels 240 - 300 x 60 x 10cm, these panels would be ideal to make OBs from. Supporting side panels could be made from the same - to any shape you like.
Supporting big heavy woofers would of course need to be clamped via the back naturally, I personally would think about using bitumen felt as gaskets, pretty not but very effective.
It is the availability of curved panels that I find very interesting, either used as sound re-inforcement behind OBs or similar and as back walls for enclosures. How would that effect filling for enclosures - lots of experiments there, remeber no hard reflective surfaces.
I would think that an effective base of any construction would be pieces of marine ply or MDF of a good thickness to enable castors to be fitted so precise placement would be easy for best sound. It may not be nec. to retrofit spikes like my favourite Norwegian Soundcare spikes.
Ytong/Xella now provide many different finishes for this material, you can in fact paper direct onto to this.
MDF is not ideal for speaker enclosures and was only adopted because HDF - high density chipboard blunted cutting equipment quickly ie. it hurt profits. Both MDF and Marine ply are heavy materials, does this benefit sound reproduction?
This material is worthy of investigation for not so much money, it has excellent acoustic properties, can be shaped into virtually any shape you like and the curved panels really do warrant empirical research.
However if you take entrenched attitudes with you then maybe better not to bother.
Black Stuart said:
I commented on your erroneous statement on stiffness.
I never made any comment on suitability to build enclosures, whether house sized or other.
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It is aerated concrete (or cellular concrete), see wikipedo.
It has nothing to do with airkrete which is a completely different material.
As a construction material, it has various nice properties. It is light (compared to non-aerated materials), easy to work with, and available in many sizes.
Thermally, it is not very good (λ = 0.09 W/m.K with modern insulation materials around 0.04) until you also factor in the fact that it is also a construction material, so if you make walls with 20cm thick blocks, it will have roughly the same insulation as a concrete wall with about 10cm fiberglass, while using about the same total thickness and less labour. Also there are no thermal bridges which is nice. And both sides are ready to finish and look nice. It compares favorably to cinderblocks and the like, since once you've built your wall, you're done, no more work needed for insulation.
Mechanically it is rather soft. You can crush a small piece of it between your fingers. This is a useful property since it makes it easy to work with. The thin blocks are very easy to break. However when the panels are glued together using the specified cement-based mortar, they become much stronger. You can bash a wall made of this material with a mace, it will penetrate a bit and make a hole, but if you want to break the wall itself, it is not that easy.
For example I had to install a window in an opening that was in the shape of a half-circle. I used a standard rectangular window, and cellular concrete to fill the rest of the opening. Cutting it in an arc shape is not difficult, I simply used a saw. It is waterproof and insulating.
In my house, I poured a concrete slab on ground floor. Before that, I placed blocks of cellular concrete horizontally in the openings where I would later install doors leading to the outside. This prevents the usual flaw of the concrete slab making a thermal bridge below the door, and losing heat. My infrared thermometer says it really works.
It has a low compression strength (compared to concrete) but if the load is spread, it is sufficient to build a house. Concrete actually has way too much strength than what is needed to build a house wall.
This material is also very bad at transmitting structure borne noise (unlike concrete which is very good at this). This is a very useful property... this comes from the fact that it is not very stiff, and yields just a bit under compression, with some damping.
I would not use it for open baffle loudspeaker enclosures because it is brittle, it will definitely break if you use a single block. If you make a box out of it, then it should be OK if the speaker holes are small. For open-baffle, you'd need to make a U-frame to strenghten it.
I mean if you take a standard 625mm x 500mm x 50mm block and make a speaker hole in the middle for a 30cm driver, you'll be lucky if the block does not break while you're working.
On the other hand, if you glue some blocks and make a 1m x 1m sheet, add some reinforcement on the edges, then make the speaker hole, it should be rather solid.
Note that if you do the knuckle rap test on a 5cm thick block, you will notice it has some resonances in the midrange. Much less than a concrete block of the same size, but not dead.
> I live in France and they use 7/8 cm cavity clay blocks for most if not all internal walls
For houses built before 1950, yeah.
>Or to comply with the latest regs using metal studding filled with rock wool and finished with only one skin of plasterboard
That isn't to comply with regulations, it's because it's cheaper. You can get nice acoustic properties with plasterboard but it is a bit more expensive, like using double thickness skin and one set of metal studs for each side.
> This material is now being used to construct sound studios and I am not surprised.
That's because it is bad at conducting sounds from the outside, which is nice.
Inside the room it will have the same reverberation as any solid surface, ie, quite high.
It has nothing to do with airkrete which is a completely different material.
As a construction material, it has various nice properties. It is light (compared to non-aerated materials), easy to work with, and available in many sizes.
Thermally, it is not very good (λ = 0.09 W/m.K with modern insulation materials around 0.04) until you also factor in the fact that it is also a construction material, so if you make walls with 20cm thick blocks, it will have roughly the same insulation as a concrete wall with about 10cm fiberglass, while using about the same total thickness and less labour. Also there are no thermal bridges which is nice. And both sides are ready to finish and look nice. It compares favorably to cinderblocks and the like, since once you've built your wall, you're done, no more work needed for insulation.
Mechanically it is rather soft. You can crush a small piece of it between your fingers. This is a useful property since it makes it easy to work with. The thin blocks are very easy to break. However when the panels are glued together using the specified cement-based mortar, they become much stronger. You can bash a wall made of this material with a mace, it will penetrate a bit and make a hole, but if you want to break the wall itself, it is not that easy.
For example I had to install a window in an opening that was in the shape of a half-circle. I used a standard rectangular window, and cellular concrete to fill the rest of the opening. Cutting it in an arc shape is not difficult, I simply used a saw. It is waterproof and insulating.
In my house, I poured a concrete slab on ground floor. Before that, I placed blocks of cellular concrete horizontally in the openings where I would later install doors leading to the outside. This prevents the usual flaw of the concrete slab making a thermal bridge below the door, and losing heat. My infrared thermometer says it really works.
It has a low compression strength (compared to concrete) but if the load is spread, it is sufficient to build a house. Concrete actually has way too much strength than what is needed to build a house wall.
This material is also very bad at transmitting structure borne noise (unlike concrete which is very good at this). This is a very useful property... this comes from the fact that it is not very stiff, and yields just a bit under compression, with some damping.
I would not use it for open baffle loudspeaker enclosures because it is brittle, it will definitely break if you use a single block. If you make a box out of it, then it should be OK if the speaker holes are small. For open-baffle, you'd need to make a U-frame to strenghten it.
I mean if you take a standard 625mm x 500mm x 50mm block and make a speaker hole in the middle for a 30cm driver, you'll be lucky if the block does not break while you're working.
On the other hand, if you glue some blocks and make a 1m x 1m sheet, add some reinforcement on the edges, then make the speaker hole, it should be rather solid.
Note that if you do the knuckle rap test on a 5cm thick block, you will notice it has some resonances in the midrange. Much less than a concrete block of the same size, but not dead.
> I live in France and they use 7/8 cm cavity clay blocks for most if not all internal walls
For houses built before 1950, yeah.
>Or to comply with the latest regs using metal studding filled with rock wool and finished with only one skin of plasterboard
That isn't to comply with regulations, it's because it's cheaper. You can get nice acoustic properties with plasterboard but it is a bit more expensive, like using double thickness skin and one set of metal studs for each side.
> This material is now being used to construct sound studios and I am not surprised.
That's because it is bad at conducting sounds from the outside, which is nice.
Inside the room it will have the same reverberation as any solid surface, ie, quite high.
peufeu,
I can't agree with most of what you have written. not sure where to start.
Please state precisely what modern insulation materials have a U value of 0.04. and are suitable both financially and practically for construction?
30cm Thermopierre blocks (the French name) with a crepi finish meet and exceed the regs.
Why would anyone want to use 'dense concrete' blocks - they absorb water like a sponge, have a very low insulation value and most importantly they are a 'heat sump', I'm sure AndrewT can explain what a 'heat sump' is.Also it needs stronger foundations due to their weight.
If you used a dense concrete slab I hope you used insulation material above it or you most certainly will have cold striking up from below. If you had used foundation aercrete blocks this would have helped at the perimeter. Presumably you also used ceramic tiles on top of the concrete - very cold and contributes a lot to the awful ringing in French homes. Presumably you also used dense concrete lintels - a classic cold bridge, which does'nt happen with aercrete lintels.
You've completely misunderstood the properties of aercrete material. It's acoustic and thermal properties are down to the millions of air bubbles.
It is not brittle unless you hit it with something , now who is going to do that?
No one is suggesting using 5cm thick blocks but also you completely misunderstand how strong it actually is eg. there is no need to use special fixings. If it was really that weak, nothing would hold fast would it?
Have you ever actually built a house using this material? You see I first worked with this material in 1979 and have since built houses and apartment blocks using it, so I am talking from experience and not theory.
You mention those awful cavity clay blocks - zero thermal and acoustic insulation - that's why French homes are so noisy, I mean really noisy compared to construction in the UK/Scandinavia/Germany etc. I guess most French people have grown up with this as standard so don't notice it.
I cannot believe what you are saying about plasterboard - it destroys the bass of a sound system and in the UK best practice is double skin, single skin is just a cowboy approach.
Yes I know what French builders use to meet the Regs. Awful multicell cavity clay blocks where the best bricklayer in the universe cannot help but create cold bridges along the entire length of the first course (1st layer) - take a look at any wall built using this method and you will see the damp stain anywhere from 5-15cm (depending on how much mortar dropped there). Then galvanised steel stud work (what happens when it begins to rust?). Rockwool insulation also has a very limited life. Including a crepi finish on the exterior that's 5 operations but only 2 using 30cm aercrete and a crepi finish.
This is most definately not the cheapest way to meet the Regs but is how the French builder can screw more money from a client.
Again you are quite right about external acoustic insulation but quite wrong about internal acoustics - think, if this material is very good acoustically from the outside and is the same material on it's inner face - how can it's properties be different.
You most definately are not a constructor otherwise you would have written a totally different post.
I live in the Aveyron - when I have built my house using only aercrete for the walls and aercrete roofing beams as well - expensive maybe but way better than traditional methods which surprise, surprise work out more expensive. I will have a home that is fireproof, insect proof, will not absorb water, will require far less heating and will be blessedly quieter than any French built home.
Take a look on RT1 after the news and look for the Leroy Merlin slot - the noise from these designs has to be heard to be believed.Then I will pm you and you can visit and see for yourself.
Andrew T - this thread is about experimenting with using this material for use with speakers. I only replied to peufeu because others might be misled by his post. Do remember that this material has been around since 1924, if it was crap it would have faded away long before now. Incidently have you ever worked with this material?
I can't agree with most of what you have written. not sure where to start.
Please state precisely what modern insulation materials have a U value of 0.04. and are suitable both financially and practically for construction?
30cm Thermopierre blocks (the French name) with a crepi finish meet and exceed the regs.
Why would anyone want to use 'dense concrete' blocks - they absorb water like a sponge, have a very low insulation value and most importantly they are a 'heat sump', I'm sure AndrewT can explain what a 'heat sump' is.Also it needs stronger foundations due to their weight.
If you used a dense concrete slab I hope you used insulation material above it or you most certainly will have cold striking up from below. If you had used foundation aercrete blocks this would have helped at the perimeter. Presumably you also used ceramic tiles on top of the concrete - very cold and contributes a lot to the awful ringing in French homes. Presumably you also used dense concrete lintels - a classic cold bridge, which does'nt happen with aercrete lintels.
You've completely misunderstood the properties of aercrete material. It's acoustic and thermal properties are down to the millions of air bubbles.
It is not brittle unless you hit it with something , now who is going to do that?
No one is suggesting using 5cm thick blocks but also you completely misunderstand how strong it actually is eg. there is no need to use special fixings. If it was really that weak, nothing would hold fast would it?
Have you ever actually built a house using this material? You see I first worked with this material in 1979 and have since built houses and apartment blocks using it, so I am talking from experience and not theory.
You mention those awful cavity clay blocks - zero thermal and acoustic insulation - that's why French homes are so noisy, I mean really noisy compared to construction in the UK/Scandinavia/Germany etc. I guess most French people have grown up with this as standard so don't notice it.
I cannot believe what you are saying about plasterboard - it destroys the bass of a sound system and in the UK best practice is double skin, single skin is just a cowboy approach.
Yes I know what French builders use to meet the Regs. Awful multicell cavity clay blocks where the best bricklayer in the universe cannot help but create cold bridges along the entire length of the first course (1st layer) - take a look at any wall built using this method and you will see the damp stain anywhere from 5-15cm (depending on how much mortar dropped there). Then galvanised steel stud work (what happens when it begins to rust?). Rockwool insulation also has a very limited life. Including a crepi finish on the exterior that's 5 operations but only 2 using 30cm aercrete and a crepi finish.
This is most definately not the cheapest way to meet the Regs but is how the French builder can screw more money from a client.
Again you are quite right about external acoustic insulation but quite wrong about internal acoustics - think, if this material is very good acoustically from the outside and is the same material on it's inner face - how can it's properties be different.
You most definately are not a constructor otherwise you would have written a totally different post.
I live in the Aveyron - when I have built my house using only aercrete for the walls and aercrete roofing beams as well - expensive maybe but way better than traditional methods which surprise, surprise work out more expensive. I will have a home that is fireproof, insect proof, will not absorb water, will require far less heating and will be blessedly quieter than any French built home.
Take a look on RT1 after the news and look for the Leroy Merlin slot - the noise from these designs has to be heard to be believed.Then I will pm you and you can visit and see for yourself.
Andrew T - this thread is about experimenting with using this material for use with speakers. I only replied to peufeu because others might be misled by his post. Do remember that this material has been around since 1924, if it was crap it would have faded away long before now. Incidently have you ever worked with this material?
This is nonsense.
A material is either brittle or not.
It does not need one to "hit it" to become brittle.
Toffee is brittle when cold.
Steel is brittle when cold.
Glass is brittle when cold.
You do not need to hit them..
If you want to find out how brittle, or malleable, then you test them. One test would be to hit them. But hitting them does not make them brittle. It makes them break.
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Are you describing aerated concrete as "crap".
I didn't.
Did you read my profile?
I am a retired professional who works/worked with many construction materials.
Of course I have much experience with aerated concrete and non aerated concrete. I would not be a Civil Engineer if it had no experience with concrete.
To become qualified one needs to prove one's abilities in a wide range of materials and disciplines.
It is so common in Europe and in many very different grades that it must be available (under different trade names) in the USA and Canada.
Hi,
FWIW allthough an interesting material I can't any great
applicability to loudspeaker enclosures, though of course
you could use it, but I can't see why you should.
I find it quite amusing "real" concrete soaks up water,
are you saying that this stuff doesn't ? Highly unlikely.
I find its alleged acoustic properties to be conjecture.
rgds, sreten.
FWIW allthough an interesting material I can't any great
applicability to loudspeaker enclosures, though of course
you could use it, but I can't see why you should.
I find it quite amusing "real" concrete soaks up water,
are you saying that this stuff doesn't ? Highly unlikely.
I find its alleged acoustic properties to be conjecture.
rgds, sreten.
Mostly poly (styrene, urethane), you can get 0.04 or below, but these are strictly insulators, not load-bearing construction materials.
> 30cm Thermopierre blocks (the French name) with a
> crepi finish meet and exceed the regs.
Yes that's what I said above, if you compare the same thickness as a standard "modern" construction (20cm cinderblock/parpaing creux, 10cm gyproc/placo+wool) you get better insulation with cellular concrete, plus a lot of desirable properties like no thermal bridges, can drill a hole anywhere to fasten something, etc.
> Why would anyone want to use 'dense concrete' blocks
Cause it's cheap, industrialized, and everybody does it. The resulting houses are crap.
Our standard system of construction is quite atrocious I think. Parpaings Creux have zero thermal insulation and their only advantage is price. Adding insulation from the inside creates homes that are very hot in summer especially the upstairs bedrooms. And after 20 years the wool tends to fall down a little... it is very sad to see all these new houses being built with a system that has been obsolete for decades.
Plus most of them are turned the wrong way around because politicians decided land had to be unaffordable.
I live in an old stone house that I renovated. It has the right side facing south. It is much more comfortable. It would be easy to have the same level of comfort with modern construction though, just by picking the right materials (ie, put lots of thermal inertia in the floor/internal walls, use cellular concrete for external walls, well insulated double skin roof, sunshade on windows facing south, etc) but ... almost noone does it.
> If you used a dense concrete slab I hope you used insulation material above
Polyurethane foam is between the slab that was originally in the house and the one I poured.
> Presumably you also used ceramic tiles on top of the concrete
Yes. Ceramic tiles are the best for underfloor heating.
> You've completely misunderstood the properties of aercrete material.
Nope, re-read my post above, I'm saying the same as you...
> Have you ever actually built a house using this material?
Nope, used it in various renovation projects, it is very useful.
> You see I first worked with this material in 1979 and have since
> built houses and apartment blocks using it, so I am talking from
> experience and not theory.
Well, congrats for raising the level on the (abysmally low) construction standards here.
> You mention those awful cavity clay blocks - zero thermal and acoustic insulation
The old ones are like parpaing but red.
The new ones (monomur) are not bad thermally, but difficult to cut, so the masons usually screw it up. They built a house with these a block from my place, every time I went by I watched the guys work... so far so good... then they did screw it up, put a nicely broken block in and filled the hole with mortar... voilà... I've never seen a monomur house without those kind of screwups...
> that's why French homes are so noisy
Yep, hate that too, just clap your hands and it sounds like a bathroom.
This has nothing to do with wall material though, since the acoustic reflection of a wall above a few hundred Hz is entirely dependent on its surface properties only.
> I cannot believe what you are saying about plasterboard - it destroys
> the bass of a sound system and in the UK best practice is double skin,
> single skin is just a cowboy approach.
Single skin is cheap and the client will not notice it, so that is what gets used. I agree that it is crap, you can hear someone blink in the next room. With the standard 48mm single studs it also makes a nice bass trap. You can do nice things with plasterboard but it needs thinking and a bit extra money. I have only one wall made of those, so I used double 70mm studs and double skin, didn't cost me a lot more., and it was fun to assemble.
I have a friend who builds houses and various types of buildings. Last year we visited a huge house he just bought, with the aim to cut it into apartments and sell it. Old stone house, thick walls, etc. So I was trying to convince him to put the insulation on the outside so all the buyers don't need to install air conditioning. He says "CIty planning wants the outside aspect of the building unchanged so we can't touch the outside, so it will be Placo, laine de verre, and that's it'. Note this is in a place in the countryside that no-one ever comes to or looks at.
> Again you are quite right about external acoustic insulation but quite wrong
> about internal acoustics - think, if this material is very good acoustically
> from the outside and is the same material on it's inner face - how can
> it's properties be different.
Completely different, acoustic transmission inside a material depends on the wave propagation medium, ie rigidity and damping, these are bulk material properties, and interaction between layers if the wall has several layers.
For example cellular concrete has high internal damping and much lower rigidity than concrete or metal, so it is bad at transmitting sound waves, therefore nice for walls.
Old fashioned Concrete has little damping and is extremely rigid, so waves propagate very well in it. It is very heavy, so airborne noise has trouble penetrating it, but contact noise, like the neighbor upstairs walking, is transmitted extremely well.
Parpaing Creux combines the worst of both : it is light, so airborne noise from outside makes it move ; it is rigid and undamped, so the vibration propagates very well to the other side.
Acoustics inside a room depends on surface reflections, again above a few hundred Hz, this is entirely determined by the surface properties of the material, not the bulk. Any wall, no matter the material, which has a reasonably hard surface, will have the same acoustic reflection properties.
Unless you use a porous paint/enduit on your walls, then it could make an absorber ?...
My ceiling (made of placo btw) is not horizontal... I put a slight angle in it. It is not flat either, it is a bit curved. It is very hard to see. Also in an old house, there are no parallel walls. I added some curtains, sofas etc. My living room does not sound like a bathroom.
A friend has a peculiar apartment, below the roof. The roof of that building is like a cylinder, so the ceiling is like the inside of a cylinder. Although the construction is 100% crap (plasterboard with half the studs "optimized out") it sounds OK and not screaming reverberant, probably because of the shape.
Other rooms which are basically cubes sound like I need to put a cushion on my ears.
> Incidently have you ever worked with this material?
Yes. It is a very useful material.
I'd like info on these arecrete roofing beams. I'm curious how they work.
> It is not brittle unless you hit it with something
It is brittle and soft. That doesn't change the fact that it is an excellent material for construction. But for building a speaker enclosure, you'd need a lot of care.
> Anyone know if this stuff or the equivalent is made/sold in the USA?
YTONG
Sounds chinese, but it isn't.
My employer had them in a block of single storey offices built in the early '60s
I had to install a stronger roof over the new computer room to hold the computer cooling equipment.
The aerated concrete panels were reinforced on the bottom side with an asymmetrical mesh. The panels are quite flexible compared to the same thickness of non-aerated concrete with the same reinforcement. Walking across the roof I could feel the roof bounce and I was not heavy, 67kg at that time.
AndrewT,
I realised you were a C/E but your input had nothing to do with what the thread was about. Bouncing around on a roof - so what - did it collapse? You will ofcourse know that aercrete roofing beams are made using 6mm re-inforcing steel. The huge advantage this has over traditional methods is simple - the roof is fireproof. The French unlike the English and Scots never cut all their forests down and France is blessed with woods and huge forests over much of France ergo it pays to have a fireproof roof system.
By all means input with relevance to the thread but it just comes across as threadcrapping.
peufue, had you included in your first post your obvious knowledge of what most French building methods are it would have saved me posting a long and unneccessary and adversarial post in reply please accept my apologies.
I am renting an old house in the Aveyron and I cannot wait to build a home that is comfortable to live in because this old house certainly is'nt.
You have well illustrated the reasons why builders don't use these kinds of material - more time, more profit - sad to say that this applies in all countries, there are exceptions and I like to think that I am one, I got all my work by recommendation.
Do visit a Gedimat or Leroy Merlin and pick up a Ytong brochure. If I was going to renovate an old house I would definately use their large panels which use stand-off brackets and require an airgap, without a doubt the best and most cost effective way to insulate stone walls. You raised a very good point about the cellular cavity clay blocks - just how the hell do you cut them to obtain a half block to maintain bond - quien saves?
Your point about rooms with all right angles is spot on. In the UK nearly all rooms are constructed using coving (used at the interface between walls and ceilings) goes a some way to ameliorate the right angles.
Interesting your point about a slight angle for the ceiling. I intend to build the roof with a shallow angle and the personal/music rooms (sanity zones) and the salon will have ceilings created by the roof angle. I intend to use crepi (not the internal vinyl kind) as a finish - no hard reflective surfaces.
You will know that these aercrete blocks have an excellent acoustic finish and I most certainly will not be using finish plaster just organic (expensive) paint. Vinyl paint is extremely toxic and I wll not have it anywhere in my home. The Danes recognise this as many of their decorators have developed severe health problems which they define as 'painters dementia' - this is serious stuff.
Renovation is way more expensive than building from new - all those Regs. that you have to comply with. BTW I was working out how much it would cost to comply with the new Regs and was surprised at the low figure for the walls both external and internal. Should you ever go for a new build I have worked an ingenious way to comply with the Regs. and save 30% on external walls and about 50% on internal walls - PM me for details.
The roofing panels strengtht comes from using 6mm re-inforcing steel. When I consider the traditional alternatives - 1st stage roof strusses, including toxic insectacide, 2nd stage fibre board decking, 3rd stage waterproof membrane, fourth stage battens, 5 stage expensive slates or heavy cement or clay tiles, 6th stage (interior) rockwool insulation,7th stage plasterboard.
If I can get it past planning I want to use white heat reflective metal panels, easy to handle, much cheaper and will not be smashed to pieces by the golf ball sized hail we get nowadays. Between the beans and the panels use blown polyurethane foam. bewteen the foam and the felt it should neagte any noise from heavy rain and hail.
sreten, your commenting without any knowledge of the materials concerned - FYI aercrete blocks absorb a maximum of 3% water. When you have done some research you will understand why dense concrete absorbs water easily and why it is a heat sump.
Why would anyone want to experiment with this material ? - simple really - non reflective, no smooth finish and with these new curved 10cm pieces no internal angular surfaces, easy to shape the edges of baffles, light weight compared to MDF or ply - why not engage in some empirical research, theory from practice?
bear, yes it is and if I lived anywhere in the southern States there is no way I would build using timber which termites just love, also a big problem in humid parts of France. This would also apply if I lived in the twister belt - I doubt if you'd lose your roof.
Americans mostly are more open to new ideas than Europeans - Joni's words ring so true "old and cold and settled in their ways" - right on the money , of course there are exceptions like peufeu and myself.
I don't know if the curved aercrete is available in the US but just 'normal enclosures would be worth experimenting with - don't forget that whatever you build would have to be set on a piece of thick MDF or preferably ply. Easy to find a bonding agent for this. Since this material does'nt absorb vibrations easily, could be worth thinking about using castors rather spikes - think how easy it would be to move them and find the sweet spot.
I'm going to buy some of the curved blocks and some 10cm panels to play around with. It will be easy to create attractive supporting side panels. For the exterior I will use a 5-1 Unibond wash to stabilise the exterior but I would'nt use it on the interior, I think it would negate a lot of the benefits of the material.
I shan't return to this thread until I have done some practical work which will either support my assertions or demolish them - vamos a ver.
I realised you were a C/E but your input had nothing to do with what the thread was about. Bouncing around on a roof - so what - did it collapse? You will ofcourse know that aercrete roofing beams are made using 6mm re-inforcing steel. The huge advantage this has over traditional methods is simple - the roof is fireproof. The French unlike the English and Scots never cut all their forests down and France is blessed with woods and huge forests over much of France ergo it pays to have a fireproof roof system.
By all means input with relevance to the thread but it just comes across as threadcrapping.
peufue, had you included in your first post your obvious knowledge of what most French building methods are it would have saved me posting a long and unneccessary and adversarial post in reply please accept my apologies.
I am renting an old house in the Aveyron and I cannot wait to build a home that is comfortable to live in because this old house certainly is'nt.
You have well illustrated the reasons why builders don't use these kinds of material - more time, more profit - sad to say that this applies in all countries, there are exceptions and I like to think that I am one, I got all my work by recommendation.
Do visit a Gedimat or Leroy Merlin and pick up a Ytong brochure. If I was going to renovate an old house I would definately use their large panels which use stand-off brackets and require an airgap, without a doubt the best and most cost effective way to insulate stone walls. You raised a very good point about the cellular cavity clay blocks - just how the hell do you cut them to obtain a half block to maintain bond - quien saves?
Your point about rooms with all right angles is spot on. In the UK nearly all rooms are constructed using coving (used at the interface between walls and ceilings) goes a some way to ameliorate the right angles.
Interesting your point about a slight angle for the ceiling. I intend to build the roof with a shallow angle and the personal/music rooms (sanity zones) and the salon will have ceilings created by the roof angle. I intend to use crepi (not the internal vinyl kind) as a finish - no hard reflective surfaces.
You will know that these aercrete blocks have an excellent acoustic finish and I most certainly will not be using finish plaster just organic (expensive) paint. Vinyl paint is extremely toxic and I wll not have it anywhere in my home. The Danes recognise this as many of their decorators have developed severe health problems which they define as 'painters dementia' - this is serious stuff.
Renovation is way more expensive than building from new - all those Regs. that you have to comply with. BTW I was working out how much it would cost to comply with the new Regs and was surprised at the low figure for the walls both external and internal. Should you ever go for a new build I have worked an ingenious way to comply with the Regs. and save 30% on external walls and about 50% on internal walls - PM me for details.
The roofing panels strengtht comes from using 6mm re-inforcing steel. When I consider the traditional alternatives - 1st stage roof strusses, including toxic insectacide, 2nd stage fibre board decking, 3rd stage waterproof membrane, fourth stage battens, 5 stage expensive slates or heavy cement or clay tiles, 6th stage (interior) rockwool insulation,7th stage plasterboard.
If I can get it past planning I want to use white heat reflective metal panels, easy to handle, much cheaper and will not be smashed to pieces by the golf ball sized hail we get nowadays. Between the beans and the panels use blown polyurethane foam. bewteen the foam and the felt it should neagte any noise from heavy rain and hail.
sreten, your commenting without any knowledge of the materials concerned - FYI aercrete blocks absorb a maximum of 3% water. When you have done some research you will understand why dense concrete absorbs water easily and why it is a heat sump.
Why would anyone want to experiment with this material ? - simple really - non reflective, no smooth finish and with these new curved 10cm pieces no internal angular surfaces, easy to shape the edges of baffles, light weight compared to MDF or ply - why not engage in some empirical research, theory from practice?
bear, yes it is and if I lived anywhere in the southern States there is no way I would build using timber which termites just love, also a big problem in humid parts of France. This would also apply if I lived in the twister belt - I doubt if you'd lose your roof.
Americans mostly are more open to new ideas than Europeans - Joni's words ring so true "old and cold and settled in their ways" - right on the money , of course there are exceptions like peufeu and myself.
I don't know if the curved aercrete is available in the US but just 'normal enclosures would be worth experimenting with - don't forget that whatever you build would have to be set on a piece of thick MDF or preferably ply. Easy to find a bonding agent for this. Since this material does'nt absorb vibrations easily, could be worth thinking about using castors rather spikes - think how easy it would be to move them and find the sweet spot.
I'm going to buy some of the curved blocks and some 10cm panels to play around with. It will be easy to create attractive supporting side panels. For the exterior I will use a 5-1 Unibond wash to stabilise the exterior but I would'nt use it on the interior, I think it would negate a lot of the benefits of the material.
I shan't return to this thread until I have done some practical work which will either support my assertions or demolish them - vamos a ver.
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