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    •  
      CommentAuthordjh
    • CommentTimeDec 4th 2017
     
    I think Nick was asking about the specific project you posted photos of.
  1.  
    @djh, yes, thanks, I was.

    @Bauwer, ''Sure if you improve U value of your 100 years old home at least by two or three times it helps a lot, as the rate of heat bleeding would be reduced by 2 to 3 times correspondingly''. Yes it does, but if you can improve it by even more it helps even more.
    •  
      CommentAuthorBauwer
    • CommentTimeDec 4th 2017
     
    Posted By: Nick Parsons@djh, yes, thanks, I was.

    @Bauwer, ''Sure if you improve U value of your 100 years old home at least by two or three times it helps a lot, as the rate of heat bleeding would be reduced by 2 to 3 times correspondingly''. Yes it does, but if you can improve it by even more it helps even more.


    Not necessary Nick, especially if you improve traditionally built home with petroleum based non breathable insulation. The key requirement for old stone or brick walls without cavity is breathability in my view.

    Just think about that - the target for 40 years old cavity wall insulation is 0.55 (building reg L1B) clearly you can not (and should not) request a more chalanging target for 100 years old wall design.

    It is like asking a 100 years old car to drive with the speed of a modern car....it just does not make sense.
  2.  
    ''Just think about that - the target for 40 years old cavity wall insulation is 0.55 (building reg L1B) clearly you can not (and should not) request a more chalanging target for 100 years old wall design.

    It is like asking a 100 years old car to drive with the speed of a modern car....it just does not make sense.''

    Hmmm...

    The target for a cavity-walled house is 0.55 because the house has a 50mm cavity which, when filled with 'fluff', gives a U value of .... wait for it ... 0.55W/m2K. The reason, I think, is to avoid a revolt in Middle England.

    With solid-walled houses the starting-point is worse, and the potential result better.

    I do not disagree with you re breathability. I was involved with the EWI of a solid-walled house using 180mm of wood-fibre and lime render. Breathability and a massive reduction in U value (less than 0.22). The '100-year-old car' is doing very well.
    • CommentAuthorgravelld
    • CommentTimeDec 5th 2017
     
    Sorry if I missed this, but what's the lambda (of the Light product)?

    How does it compare in installation costs to stick block (EPS) and render?

    I'm thinking maximum possible thickness (150mm on your calculator).
    • CommentAuthorMarkyP
    • CommentTimeDec 5th 2017 edited
     
    can this render really compete with EPS or wood fibre where there is more than 50mm of additional build up available? How thick can it be built up per coat? 30 or 40mm of insulated render perhaps a good option where you are constrained on external build up thickness for some reason. But as soon as you can get a 40 or 50mm EPS board on the wall the render only option is going to be trumped. Much is made of breathability, indeed Bauwer's webiste says the render is both breathable and dehumidifying! If you really need a very vapour open wall then as mentioned wood fibre/lime will do nicely, but lots of period property out there with a coat of EPS and they seem to be doing just fine. I'd consider a product like this if I had less than 50mm to play with, otherwise I'd be willing to bet EPS or woodfibre will be faster, cheaper to install and achieve a far superior u-value.
    •  
      CommentAuthorBauwer
    • CommentTimeDec 12th 2017 edited
     
    Hello Nick,
    Sorry for my slow reply, we are extremely busy with the number of orders at that cold time.

    My comments:
    "I was involved with the EWI of a solid-walled house using 180mm of wood-fibre and lime render. Breathability and a massive reduction in U value (less than 0.22). The '100-year-old car' is doing very well"

    a) 0.22 is declared performance while actual performance could be significantly worse due to links between boards being potential "cold bridges" while Bauwer delivers seamless insulation without a need to link boards.

    b) stone homes have rough walls which must be leveled first before boards application, Bauwer does not require any leveling. Actually Bauwer likes rough wall as it is an additional key. Also Bauwer is the most cost efficient way to level the stone walls as it is light-weight and strong highly breathable material.

    c) if wooden fibre board used internally it could lead to condensation issues.

    d) Bauwer is inorganic and nutrural based on vulcanic sand Perlite while wood is organic material could be impacted by water, etc

    e) Please advise what was the cost per sqm both material and labour. Bauwer material is times more cost competitive:
    https://www.homebuilding.co.uk/how-to-insulate-solid-stone-wall-homes/

    f) the main benefit of lower U value is saving on your energy bill and related carbon emissions. Sure the cost of the project should be balanced with the energy savings and improvement of U value by 3 to 4 times are generally sufficient for vast majority of stone wall customers assuming budget cost of Bauwer insulation.

    I could continue with my bullet points:
    http://bauwer.co.uk/templates/Default/images/Leaflet.pdf

    Please do not hesitate to contact me should you require any further information at 0151 558 0890

    Regards, Alexander
    info@bauwer.co.uk
    •  
      CommentAuthorBauwer
    • CommentTimeDec 12th 2017
     
    <blockquote><cite>Posted By: gravelld</cite>Sorry if I missed this, but what's the lambda (of the Light product)?

    How does it compare in installation costs to stick block (EPS) and render?

    I'm thinking maximum possible thickness (150mm on your calculator).</blockquote>

    Honestly speaking EPS should not be used for stone walls traditionally build homes insulation:
    https://www.homebuilding.co.uk/how-to-insulate-solid-stone-wall-homes/

    Bauwer insulation is one of the most cost competitive way to insulate solid stone walls on the market.

    Based on the Building regulations L1B, part 5.12 U value of 0.7 or lower need to be achieved by solid stone or brick walls.
    •  
      CommentAuthorBauwer
    • CommentTimeDec 12th 2017 edited
     
    <blockquote><cite>Posted By: MarkyP</cite>can this render really compete with EPS or wood fibre where there is more than 50mm of additional build up available? How thick can it be built up per coat? 30 or 40mm of insulated render perhaps a good option where you are constrained on external build up thickness for some reason. But as soon as you can get a 40 or 50mm EPS board on the wall the render only option is going to be trumped. Much is made of breathability, indeed Bauwer's webiste says the render is both breathable and dehumidifying! If you really need a very vapour open wall then as mentioned wood fibre/lime will do nicely, but lots of period property out there with a coat of EPS and they seem to be doing just fine. I'd consider a product like this if I had less than 50mm to play with, otherwise I'd be willing to bet EPS or woodfibre will be faster, cheaper to install and achieve a far superior u-value.</blockquote>

    Hi MarkyP,
    as I mentioned earlier, not a very good idea using petroleum based EPS insulation for solid stone walls insulation. The reasons are well explained here:
    http://greenbuilding.co.uk/insulating-masonry-walls-of-old-stone-cottages-and-listed-buildings/

    The issues of trapped moisture in traditionally built homes are massive thanks to "experts" or not qualified architects who apply modern impermeable solutions in older buildings.

    Could you please read my post above on wooden fibre boards insulation option.

    We also offer modern insulation systems based on graphite EPS, XPS or stone wool with wide range of robust and flexible fibre reinforced finishes under Vimark brand:
    https://www.vimark.co.uk/linee-prodotti/external-insulation-systems/

    Please do not hesitate to contact me should you require any further information.

    Best regards,
    Alexander
    0151 558 0890
    •  
      CommentAuthorBauwer
    • CommentTimeDec 12th 2017 edited
     
    More projects being completed delivering cost efficient solutions.
      Dean Miller.JPG
  3.  
    *My (Nick Parsons') responses to Alexander at Bauwer are prefaced by an asterisk:

    Alexander at Bauwer wrote:

    Hello Nick,
    Sorry for my slow reply, we are extremely busy with the number of orders at that cold time.

    My comments:
    "I was involved with the EWI of a solid-walled house using 180mm of wood-fibre and lime render. Breathability and a massive reduction in U value (less than 0.22). The '100-year-old car' is doing very well"

    a) 0.22 is declared performance while actual performance could be significantly worse due to links between boards being potential "cold bridges" while Bauwer delivers seamless insulation without a need to link boards.

    *Nick P response: Yes, I agree with you that all systems must be installed well. It is a particular concern of mine that some EWI firms leave gaps between insulation boards, or allow thermal by-pass, and cover it all up with the 'icing (render) on the cake'. While a good render finish is important to me, the extremely tight fit of all boards is of fundamental importance.

    b) stone homes have rough walls which must be leveled first before boards application, Bauwer does not require any leveling. Actually Bauwer likes rough wall as it is an additional key.
    *NP response: I agree with you that uneven walls are an issue. Each case needs to be weighed up. In the case I refer to we used a wood-fibre material with a rigid face but with flexible fibre behind, allowing the board to be 'pulled in' over the irregularities we encountered in this specific case.

    Also Bauwer is the most cost efficient way to level the stone walls as it is light-weight and strong highly breathable material.



    c) if wooden fibre board used internally it could lead to condensation issues.

    *NP: My reply referred to EWI - External insulation of External walls. Any improvement to insulation of any wall could potentially lead, through poor detailing or installation or poor understanding of building physics, to condensation issues. In my view that's what fine attention to detail and dynamic condensation risk assessment tools such as WUFI are for.

    d) Bauwer is inorganic and nutrural based on vulcanic sand Perlite while wood is organic material could be impacted by water, etc

    *NP: You are quite right - wood-based insulation can be affected by moisture, and attention to detail, to avoid moisture ingress, is essential. I believe it is essential, though, for pretty well all insulants, even if the material of the insulant itself is not physically affected by water.

    e) Please advise what was the cost per sqm both material and labour.

    *NP: I do not know. I was engaged as a sub-contractor.

    Bauwer material is times more cost competitive:
    https://www.homebuilding.co.uk/how-to-insulate-solid-stone-wall-homes/

    f) the main benefit of lower U value is saving on your energy bill and related carbon emissions. Sure the cost of the project should be balanced with the energy savings and improvement of U value by 3 to 4 times are generally sufficient for vast majority of stone wall customers assuming budget cost of Bauwer insulation.

    *NP: And for those who wish to achieve lower U values other options exist.
    • CommentAuthordelprado
    • CommentTimeDec 13th 2017
     
    anyone interested in wet insulating render should also investigate baumits eps based solution which is breathable and half the price
  4.  
    Hi Delprado, is that loose beads in render, or render on EPS boards?

    Edit: Forget that Q - a quick Google says it's the former.
    • CommentAuthorgravelld
    • CommentTimeDec 13th 2017 edited
     
    Posted By: Bauwer
    Posted By: gravelldSorry if I missed this, but what's the lambda (of the Light product)?

    How does it compare in installation costs to stick block (EPS) and render?

    I'm thinking maximum possible thickness (150mm on your calculator).


    Honestly speaking EPS should not be used for stone walls traditionally build homes insulation:
    https://www.homebuilding.co.uk/how-to-insulate-solid-stone-wall-homes/" rel="nofollow" >https://www.homebuilding.co.uk/how-to-insulate-solid-stone-wall-homes/

    Bauwer insulation is one of the most cost competitive way to insulate solid stone walls on the market.

    Based on the Building regulations L1B, part 5.12 U value of 0.7 or lower need to be achieved by solid stone or brick walls.

    1) I'm not interested in stone walls and I didn't ask anything about them.

    2) The questions I did ask you didn't answer.
  5.  
    **Nick Parsons' comments denoted by double asterisks**

    Posted By: gravelld
    Sorry if I missed this, but what's the lambda (of the Light product)?

    **Stated as 0.068W/mK - see link provided above:

    http://bauwer.co.uk/templates/Default/images/Leaflet.pdf**

    How does it compare in installation costs to stick block (EPS) and render?

    I'm thinking maximum possible thickness (150mm on your calculator).

    **If we assume a 225mm solid brick wall, with a ,base case U value of 2.1W/m2K,and a lambda value for Bauwer Light of 0.068 as stated in Bauwer's leaflet, then the calc is as follows:

    0.15(m)/0.068 = R1 = 2.2058

    'Base Case R' of wall = 1/2.1 = R2 = 0.476

    R1+R2 = 2.6818

    1/R = 0.3728 = U value of 150 Bauwer Light on 225mm solid brick wall.**


    Honestly speaking EPS should not be used for stone walls traditionally build homes insulation:
    https://www.homebuilding.co.uk/how-to-insulate-solid-stone-wall-homes/" rel="nofollow" >https://www.homebuilding.co.uk/how-to-insulate-solid-stone-wall-homes/

    Bauwer insulation is one of the most cost competitive way to insulate solid stone walls on the market.

    Based on the Building regulations L1B, part 5.12 U value of 0.7 or lower need to be achieved by solid stone or brick walls.

    **I have no connection with Bauwer and have never used the product. I am just trying to present the figures in a post (rather than in a link) to answer some of gravelld's questions.


    I believe another of the links provides estimates of materials and application costs at 50 and 70mm.**

    **Edit: Yes, this is the link with the cost estimates: https://www.homebuilding.co.uk/how-to-insulate-solid-stone-wall-homes/ **
    • CommentAuthorgravelld
    • CommentTimeDec 15th 2017
     
    Thanks Nick.
    • CommentAuthorKenny_M
    • CommentTimeDec 15th 2017
     
    This has been interesting reading and just though I might throw my thoughts/experience of breathability into the mix.

    I have lived in houses over 100 years old, built from sandstone, for the last 10 years. I've read a lot about breath-ability from research done by historic Scotland and other sources and I agree that the expert opinion in this area is that it is absolutely the wrong thing to do to put non breathable insulation, or render on a house built with breathable materials.

    The house I have been living in for the last year is at least 150 years old, exposed Ashlar Sandstone blocks on the front, but the side and rear walls have been covered in a cement render for the last 30 years. My initial thought was that I need to get that ripped off and replaced with a breathable render, and that this was probably the cause of the dampness in the house.

    However, I pulled off a small section from a side wall and there is no dampness at all underneath the cement render. Having first used a dehumidifier to dry the inside of the house out, and then improved the ventilation it seems that the dampness has been due to condensation caused by water vapour produced inside the house and it is now under control.

    It strikes me that as long as the outside wall was dry when the render was applied it shouldn't matter that it can't breathe out, because there is no water going in to be breathed out. As long as the inside walls of the house remain breathable, and the inside is at a low relative humidity then, any water entering the stonework from the ground should be able to breath to the inside of the house.

    Not suggesting its good practice to cover a sandstone house with cement or EPS, but in theory a wall only needs to breathe water vapour out, if there is any going in.
    •  
      CommentAuthorBauwer
    • CommentTimeDec 20th 2017 edited
     
    Bauwer breathability demonstration video:
    https://youtu.be/-AbGjlX_c3A

    Bauwer is highly breathable Insulation for traditionally built homes with solid stone or brick walls without a cavity. Bauwer Light vapour permeability coefficient µ is only 4 which is a benchmark level among other breathable Insulation materials. In this demonstration we placed a sample of Bauwer Light in an aquarium pressurised with a basic aquarium compressor and poured some water on the top. As you could see the vapour is easily passing through Bauwer sample creating lots of bubbles. Being inorganic based on volcanic sand Perlite, Bauwer can not rot or get damaged with water vapour ingress which differentiate Bauwer from organic cork or wood fibre. Being inorganic Bauwer can not burn and can withstands temperatures of up to 900 degrees centigrade. Bauwer hardened density is only 280 kg per cubic meter which is one of the most light insulating render plaster in the group of similar materials.
    •  
      CommentAuthorBauwer
    • CommentTimeDec 20th 2017
     
    Another Bauwer internal insulation project on the go
      Bauwer material.JPG
    •  
      CommentAuthorBauwer
    • CommentTimeDec 20th 2017 edited
     
    <<<<<<<<<<< Beginning quote

    This has been interesting reading and just though I might throw my thoughts/experience of breathability into the mix.

    I have lived in houses over 100 years old, built from sandstone, for the last 10 years. I've read a lot about breath-ability from research done by historic Scotland and other sources and I agree that the expert opinion in this area is that it is absolutely the wrong thing to do to put non breathable insulation, or render on a house built with breathable materials.

    The house I have been living in for the last year is at least 150 years old, exposed Ashlar Sandstone blocks on the front, but the side and rear walls have been covered in a cement render for the last 30 years. My initial thought was that I need to get that ripped off and replaced with a breathable render, and that this was probably the cause of the dampness in the house.

    However, I pulled off a small section from a side wall and there is no dampness at all underneath the cement render. Having first used a dehumidifier to dry the inside of the house out, and then improved the ventilation it seems that the dampness has been due to condensation caused by water vapour produced inside the house and it is now under control.

    It strikes me that as long as the outside wall was dry when the render was applied it shouldn't matter that it can't breathe out, because there is no water going in to be breathed out. As long as the inside walls of the house remain breathable, and the inside is at a low relative humidity then, any water entering the stonework from the ground should be able to breath to the inside of the house.

    Not suggesting its good practice to cover a sandstone house with cement or EPS, but in theory a wall only needs to breathe water vapour out, if there is any going in.<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<End quote




    As temperature and therefore pressure is generally higher inside of the home vs outside, water vapour is pushed outside of the home. When drying to outside is blocked with impermeable material, drying to inside could lead to poor comfort, old smell in the house as well as trapped moisture.
      Old vs new.jpg
    •  
      CommentAuthorBauwer
    • CommentTimeDec 20th 2017
     
    Hi @Nick Parsons,
    Thanks for detailed answer to @gravelld, all sounds correct, thanks for that.

    Also you could also our simple U value calculator in order to calculate estimated as build U value and improved U value with Bauwer permeable insulation:
    http://bauwer.co.uk/Calculator.html?#CALCULATOR

    It is consistent with your calculation.

    Regards, Alexander
    07553353931
    •  
      CommentAuthorBauwer
    • CommentTimeDec 20th 2017
     
    <<<<<<<<<<<<Delprado quote

    anyone interested in wet insulating render should also investigate baumits eps based solution which is breathable and half the price<<<<<<<<<<<<<End quote

    Petrolium based EPS is not as vapour permeable (breathable) as natural expanded inorganic volcanic sand perlite.

    As a result, Bauwer Light is much more breathable vs EPS based Baumit with water vapour diffusion resistance µ-value for Bauwer Light is at benchmark level of 4, while DP85 is two times less breathable at 8

    Bauwer Light breathability demonstration with an aquarium:
    https://youtu.be/-AbGjlX_c3A
    • CommentAuthorKenny_M
    • CommentTimeDec 20th 2017
     
    Hi Bauwer,
    I get the theory, but my point is that if the humidity inside the house is controlled then its not likely to be a major issue. If the RH inside is low enough inside and the house is well ventilated, and to be honest a 200 year old house is usually unintentionally fairly well ventilated from leaky windows to fireplaces etc.

    If I was putting render on then I would use a breathable render, but I just saying I am no longer to take the cement render off now because in practice its not causing a problem.

    Kenny
    •  
      CommentAuthorBauwer
    • CommentTimeDec 21st 2017
     
    <<<<<<<<<<<<<< Quote Kenny_M

    Hi Bauwer,
    I get the theory, but my point is that if the humidity inside the house is controlled then its not likely to be a major issue. If the RH inside is low enough inside and the house is well ventilated, and to be honest a 200 year old house is usually unintentionally fairly well ventilated from leaky windows to fireplaces etc.

    If I was putting render on then I would use a breathable render, but I just saying I am no longer to take the cement render off now because in practice its not causing a problem.

    Kenny<<<<<<<<<<<<<<<<<End quote


    Hello Kenny,
    I agree that it is reasonable position keeping impermeable render if is it is not causing short term issues.

    Saying that there are many cases when non breathable materials applied externally or internally are damaging the traditionally built homes and therefore need to be removed in order to allow those properties to dry out to outside as designed.

    That's an interesting video on the same topic:
    https://youtu.be/GJjDRHLo2cs


    Regards, Alexander
    • CommentAuthordelprado
    • CommentTimeJan 2nd 2018
     
    Ive found another one to consider, which performs twice as well from an insulation perspective. Bauwer do you have any comments on this product?

    DIATHONITE EVOLUTION

    https://www.diasen.com/sp/en/p/diathonite-evolution.3sp

    Thanks
    • CommentAuthorKenny_M
    • CommentTimeJan 7th 2018
     
    I am interested in this too. The diathonite has better thermal conductivity and the same vapour permeability.

    The stone walls of my old house are currently rendered with cement the render is failing so it will need redone at some point. As an uneven stone surface a breathable render would seem just the ticket but I haven't come across any independent sources with any experience of this.
    • CommentAuthordelprado
    • CommentTimeJan 8th 2018
     
    the downside is that its really expensive, 35 quid a bag, so I guess its only really plausible to justify the cost if you live in an old stone house or similar
    • CommentAuthorKenny_M
    • CommentTimeJan 11th 2018
     
    Right. So the Bauwer is ~£10 a bag, but the coverage seems to be less. My quick calc says that for the equivalent thickness of 25mm the Bauwer would be £10 per metre squared versus ~18 for the Diathonite, but the Diathonite would produce a better U value for that same thickness.

    My render is boss so I need to do it anyway at some point, I must sit down and work out the relative cost for each of these, against breathable insulation + render, for a set U value and post it up.
  6.  
    £10+ VAT+ carriage. Yes, that £/R comparison would be very useful. Thanks.
    • CommentAuthorKenny_M
    • CommentTimeJan 11th 2018
     
    Here goes. Hopefully I haven't made a complete mess of this, maths not being my strong suit! Please correct me if anyone sees any calculation errors.

    Diathonite published thermal resistance is 0.222 at 10mm
    Yield of 3.70 kg/m² for 10mm thickness.
    18kg bag
    So 18/3.7 = 4.8649m per bag?
    Bag is apparently around £35
    35/(18/3.7)=£7.1944 for thermal resistance of 0.222 at 10mm

    Bauwer don't publish thermal resistance but if I am calculating correctly their published thermal conductivity at 0.68. would work out at 0.0147 at 10mm thickness
    For Bauwer to achieve a thermal resistance of 0.222 the thickness would need to be 15.1mm
    Bauwer is around £10 per 7kg bag
    1bag will cover 1m2 at 25 mm thickness
    7kg x 15.1/25 = 4.228kg
    £10 x 15.1/25 = £6.04 for thermal resistance of 0.222 at 10mm

    So, Bauwer is about 15% cheaper if the prices above are accurate, but needs to be 50% thicker for the same thermal resistance which will presumably affect labour cost, and requires around 15% more weight for shipping.

    A very quick look at external woodfibre insulation and pavatex external woodfibre insulation with a very similar thermal conductivity to the Diathonite is around £10 per sq metre for 40mm thickness so around £2.50 to for the same thermal resistance as above (0.222).

    If this is all correct then the wood fibre board is significantly cheaper, but not sure about labour costs/fixings etc, and I am not sure if a board could be applied to an uneven wall like mine.
   
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