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    • CommentAuthorchriskemp
    • CommentTimeFeb 25th 2012
     
    May I address a few things mentioned above (in no particular order).
    (I do not work for Mantle Panel)

    The Mantle Building System (MBS) has gone through rigorous testing as you would imagine.

    MBS has LABC fast track approval as a system for three and a half storeys.
    It has in excess of 1hour fire rating from chiltern.
    It is fully recyclable, back into its own process.
    It has BRE durability sign off covering min 60 years (against delamination for example).
    You get 0.1 Uvalue as standard - for walls and the roof (assuming you are having room in roof, or it will be a waste of money as per the above comment). - out of interest what Uvalue are you getting from your timber frame?
    Airtightness achievable is 1m3/hr/m2 or better. - again what is the timber frame above able to achieve?
    MBS Is frameless as the entire wall is load bearing (so the weight of the stories above is no issue) - so pretty much zero thermal bridging, other than window boards really.
    Heating load of a house become below 1kwh peak! due to a true fabric first approach. - what is your peak heat demand using timber frame?
    You need to batten out on the inside to run services as there are no service voids and you cant chase the walls.
    The insulation is a hybrid (high carbon content) EPS, NOT PU. The EPS is fire retardant and even edible (why anyone would want to eat it i dont know!).
    The EPS is extruded/expanded into moulds rather than one large chunk, and then sliced.
    If you design around 8X4 lego blocks you would have almost zero waste from MBS for true lean construction.
    Due to cement particle board being the outer skin; it is weathered straight away and can remain exposed without any wharping or water issues - unlike other systems.
    An elastomeric render is all that is required - or of course you can hang brick slips etc straight onto the skin to finish.
    MBS poses no risk of fire during construction or after construction.
    MBS is completely inert unlike other systems using other insulation materials.
    MBS can be used for basements
    MBS can be used to build atop existing buildings due to its lightweight/no frame properties.
    MBS has min 62dB noise reduction - how does that compare to timberframe as Im not sure.
    Due to no frame you can easily add to an MBS buildings and install additional windows without fear of altering structural integrity etc.

    I hope that helps clarify a few things.

    warmest regards

    chris kemp
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 25th 2012
     
    Posted By: chriskemp(I do not work for Mantle Panel)

    Who do you work for Chris?
    • CommentAuthorborpin
    • CommentTimeFeb 25th 2012 edited
     
    • CommentAuthorEd Davies
    • CommentTimeFeb 25th 2012
     
    Posted By: chriskempHeating load of a house become below 1kwh peak!


    1 kWh over what period of time?
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 25th 2012
     
    Our favourite, (or is that in effect/affect hour) :wink:
    • CommentAuthorchriskemp
    • CommentTimeFeb 25th 2012
     
    You would have to ask a SAP assessor for a proper explanation- but my understanding of X killowatt peak - is from a standing start (empty building) to a comfortable temp' ?

    So in effect you dont need a traditional wet heating system at all - as there is sufficient heat gain from TV's, occupants activities etc. Coupled with 90% MVHR to help "spread" the heat around the building.

    But should you go on hols for a week - you would only need a 1kw heater kept in cupboard under the stairs for such situations.

    (and to answer the question re: my current employement status - I have recently been made redundant - although I am not sure of the relevance?).
    •  
      CommentAuthorJSHarris
    • CommentTimeFeb 25th 2012 edited
     
    <blockquote><cite>Posted By: chriskemp</cite>You would have to ask a SAP assessor for a proper explanation- but my understanding of X killowatt peak - is from a standing start (empty building) to a comfortable temp' ?

    So in effect you dont need a traditional wet heating system at all - as there is sufficient heat gain from TV's, occupants activities etc. Coupled with 90% MVHR to help "spread" the heat around the building.</blockquote>

    I think this may have been a typo, then:

    <blockquote><cite>Posted By: chriskemp</cite>
    Heating load of a house become below 1kwh peak! </blockquote>
    as it was the unusual use of units that caused the comment from Ed and ST above, I believe, specifically the use of energy instead of power.

    What you've described, in your defence of this somewhat expensive building system, is not untypical for many houses that forum members here are interested in, although probably not quite to Passivhaus or AECB Gold standard in terms of energy efficiency. A fairly standard SIPs build will get similar performance, as would a well-sealed timber frame build or a well insulated conventional build.

    As someone who's currently looking at various build options for a new build I did spend a few hours looking at the Mantle system, but the relatively high cost/performance ratio is the primary thing that put me off.
    • CommentAuthorchriskemp
    • CommentTimeFeb 25th 2012 edited
     
    I'm trying to remember back to a project I was working on - which had the "peak heat demand" shown on the SAP calcs? Which achieved 2010 code 4 without the need for any renewables..

    Unfortunatley the client pulled the plug on the project due to finance constraints, so it didnt get built...
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 25th 2012
     
    Renewable energy technologies won't change the amount of energy needed, just where it comes from and the CO2e intensity.

    Does anyone check the long term performance of these Mantle systems houses?
    •  
      CommentAuthorJSHarris
    • CommentTimeFeb 26th 2012
     
    <blockquote><cite>Posted By: SteamyTea</cite>
    Does anyone check the long term performance of these Mantle systems houses?</blockquote>

    My only slight worry about this system, and the other foam sandwich structural systems, is the longevity of the PU/PIR foam, as it's a structural component in these panels (it forms the shear web that allows the load-bearing skins to work). The history of PU/PIR in structural composites is a bit chequered, to the point that the stuff is only now used in non-critical structures (for example, people like Lloyds won't now allow it in most structural core boat components).

    I've had personal experience of PU foam crumbling inside a composite sandwich construction component and I'm personally veering away from the idea of using SIPs now, partly for that reason (PU shares much the same properties as PIR, with regard to crumbling and shear failure in composites). Having looked at the Mantle system it seems to be structural identical to SIPs, but using cementitious board instead of OSB. They've clearly designed the system well, with modular panels that keep the need for custom fabrication down to a minimum (as long as you design to a 300 mm grid), but other than that I can't really see any advantage over SIPs.
    • CommentAuthorCav8andrew
    • CommentTimeFeb 26th 2012 edited
     
    JHS, What form of construction are you now favoring or is it still to be assessed ?
    Additional question, how long have SIPs been in existence ?
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 26th 2012 edited
     
    Same concerns as myself there.
    The large pre-fab manufacturer down near me (not mentioning any names but you know who they are) uses mineral wool as the insulation, machined timber as the structural elements and OSB to keep the weather out. Simple, cheap and effective. Good basic engineering practices, you just can't beat them.:wink:
    •  
      CommentAuthorJSHarris
    • CommentTimeFeb 26th 2012
     
    <blockquote><cite>Posted By: Cav8andrew</cite>JHS, What form of construction are you now favoring or is it still to be assessed ?</blockquote>

    I'm veering back towards timber frame, although there is a bit of a domestic going on with regard to having a "traditional" oak frame.............

    The two things I need to get reassurance on are the ability to get enough room in the roof space with conventional timber frame (we're ridge height limited and the bedrooms are in the roof space) and adequate airtightness. My experience with local builders I've spoken with hasn't filled me with confidence so far, though.
    • CommentAuthorJonti
    • CommentTimeFeb 26th 2012
     
    JSH,

    why not internal timber frame EWI and cladding. It should be possible to get as much roof space as with any other type of construction for a house (or am I missing something.:confused:).

    Jonti
    • CommentAuthorCav8andrew
    • CommentTimeFeb 26th 2012 edited
     
    What would be your concerns regarding roof space ? We have a similar situation re. limited head/build height. In fact I have just had my 3rd visit from planning compliance officers following a further complaint re. height of building (once again totally spurious, I know the finished height of the build to the nearest cm). Anyway to the point we have a ridge to eaves span of 7.2 m which was achieved using 300 mm deep I beams. There will be intermediate support close to the eaves but this will be in the form of a dwarf wall which would have been built anyway. This was calculated on a traditional slate roof on OSB but we are now probably using the Nulok system which lightens the loading. Would I beams of that kind of depth be viable on your project ?
    •  
      CommentAuthorJSHarris
    • CommentTimeFeb 26th 2012
     
    <blockquote><cite>Posted By: Jonti</cite>JSH,

    why not internal timber frame EWI and cladding. It should be possible to get as much roof space as with any other type of construction for a house (or am I missing something.<img title=":confused:" alt=":confused:" src="/forum114/extensions/Vanillacons/smilies/standard/confused.gif"></img>).

    Jonti</blockquote>

    The snag is height. If I have internal timbers in the roof, they will take up maybe 200 mm to 250 mm to cover the span needed, then I'd need another 200 mm of insulation, then battens, slates etc, pushing the total roof thickness up to around 450 mm or so I think. With SIPs I could get away with a 175 mm SIPs panel plus 60 mm of internal PIR, plus internal skinning and the roof battens, slates etc for a total roof panel thickness of around 300 mm.

    150 mm more takes a fair bit of space out of the bedrooms and bathrooms, plus it cuts down on the height of thermal store I can fit in the utility space up there, which is partly under the eaves.

    The major advantage of SIPs (and the Mantle system) to me is the clear roof span you can get. A thick SIPs panel can span enough distance to only need support from purlins along the top of the inner roof space walls, set at the BR roof window lower edge escape height of 1100 mm, plus a deep glulam ridge beam.
    • CommentAuthorJonti
    • CommentTimeFeb 26th 2012
     
    JSH,

    I have not the time to reread the entire thread at the mo. but if the 450mm is above (external) then there would not be any reduction in ceiling height. Alternatively can you not do just the roof in SIP? or is this already the plan :neutral:

    Jonti
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 26th 2012 edited
     
    •  
      CommentAuthorJSHarris
    • CommentTimeFeb 26th 2012
     
    <blockquote><cite>Posted By: Cav8andrew</cite>What would be your concerns regarding roof space ? We have a similar situation re. limited head/build height. In fact I have just had my 3rd visit from planning compliance officers following a further complaint re. height of building (once again totally spurious, I know the finished height of the build to the nearest cm). Anyway to the point we have a ridge to eaves span of 7.2 m which was achieved using 300 mm deep I beams. There will be intermediate support close to the eaves but this will be in the form of a dwarf wall which would have been built anyway. This was calculated on a traditional slate roof on OSB but we are now probably using the Nulok system which lightens the loading. Would I beams of that kind of depth be viable on your project ?</blockquote>

    Yes, this is about the depth of beam needed. If I add EWI, though, as per Jonti's suggestion, it lifts the ridge above the allowed height. I could accept the thermal bridging through the beams and just use between-the-rafters insulation, but I would rather not do this unless I have to.

    In my case I also have a finished floor height restriction imposed by the planners on behalf of the Environment Agency, so I only have 6.5 m between finished internal floor height and maximum allowable external ridge height. I also have a restriction on roof pitch, of not shallower than 40 deg, so can't just reduce the pitch to get back some more room upstairs.

    I may end up using a thick SIPs roof, unless I can find something else that would allow me to span about 3 m between a ridge beam and the top of the internal 1100 mm walls and keep to about 300 mm finished roof thickness.
    • CommentAuthorborpin
    • CommentTimeFeb 26th 2012 edited
     
    Posted By: JSHarrisMy only slight worry about this system, and the other foam sandwich structural systems, is the longevity of the PU/PIR foam,
    It is a form of EPS.
    • CommentAuthorCav8andrew
    • CommentTimeFeb 26th 2012 edited
     
    Jonti, the impact is possibly at the ridge height if there are planning restrictions and the inability to raise the roof to accommodate the additional insulation.
    JHS, Is the concern with joist the cold bridging ? if so I beams do moderate this effect, I am then able to achieve 300 mm depth of insulation (which may not be enough for your requirements) What is your max. span on roof joists ? Ridge to eaves/dwarf/intermediate support ?

    Sorry in the time taken to compose this post JHS has detailed situation
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 26th 2012
     
    Does anyone make a 'hi tech' composite beam?, they can be exceptionally rigid, very light, but may be expensive.
    •  
      CommentAuthorJSHarris
    • CommentTimeFeb 26th 2012 edited
     
    <blockquote><cite>Posted By: borpin</cite>It is a form of EPS.</blockquote>

    Sorry, I missed that when looking at the Mantle site.
    • CommentAuthorJonti
    • CommentTimeFeb 26th 2012
     
    JSH,

    so its a planning issue not a structual. I did not realise there would be a measurement from internal finished floor to external ridge height why is this rule in place?

    Jonti
    • CommentAuthorborpin
    • CommentTimeFeb 26th 2012
     
    Posted By: JSHarrisThe snag is height. If I have internal timbers in the roof, they will take up maybe 200 mm to 250 mm to cover the span needed, then I'd need another 200 mm of insulation, then battens, slates etc, pushing the total roof thickness up to around 450 mm or so I think. With SIPs I could get away with a 175 mm SIPs panel plus 60 mm of internal PIR, plus internal skinning and the roof battens, slates etc for a total roof panel thickness of around 300 mm.
    Same here in many respects. I am currently looking at using a 100mm Timber frame filled with Icynene, OSB as the air tight layer on the outside (no VCL), then 120 or 130 PIR on the outside with a Thermoblock outer skin. This gives U of 0.13/0.12 respectively and after running it through BuildDesk U there is no risk of condensation.

    The roof will be similar but the Attic trusses will only be filled to 150mm with Icynene (forms a service void), the other rafters (hipped roof) will probably be about 150 so full filled and levelled off. OSB then 100mm PIR on top for a U value of 0.12 and nil condensation risk.

    I have a joiner who can build the frame on site, I'll glue and nail the panels together to improve airtightness and glue & nail the panels to each other.

    However, the back park of the house (a T shape) is a simple 2 bay Oak Frame but I am not sure how to finish it. I have been offered SIPs but may use the same form of construction as the front part.

    The question will be why not EPS; simple depth required; I don't like the idea of such deep insulation. I am not convinced of EWI from a point of view of durability (impact resistance for the walls) or the roof with such deep insulation. Also the PIR is water impermeable making the outer layer to the OSB virtually waterproof.

    I am wondering about sticking the PIR down with something (bitumen paint?) as well as normal fixings to reduce the risk of water penetration (and air movement) even further.
    • CommentAuthorborpin
    • CommentTimeFeb 26th 2012
     
    Posted By: JSHarris
    Posted By: borpinIt is a form of EPS.
    Sorry, I missed that when looking at the Mantle site.
    It is not there but I asked. Chris Kemp also mentioned it and he seems to have some knowledge of the process to build the panels.
    • CommentAuthorCav8andrew
    • CommentTimeFeb 26th 2012
     
    Jonti, if as my situation it is not an internal measurement issue. It is an agreed overall height of building (taken from some datum point) and established at planning approval stage. Once this is fixed everything works back from it.
    • CommentAuthorJonti
    • CommentTimeFeb 26th 2012
     
    Posted By: Cav8andrewJonti, if as my situation it is not an internal measurement issue. It is an agreed overall height of building (taken from some datum point) and established at planning approval stage. Once this is fixed everything works back from it.


    Yes, but JSH specificaly states finished internal floor height.
    • CommentAuthorCav8andrew
    • CommentTimeFeb 26th 2012
     
    Jonti, sorry missed that supplementary requirement
    •  
      CommentAuthorJSHarris
    • CommentTimeFeb 26th 2012
     
    <blockquote><cite>Posted By: Jonti</cite><blockquote><cite>Posted By: Cav8andrew</cite>Jonti, if as my situation it is not an internal measurement issue. It is an agreed overall height of building (taken from some datum point) and established at planning approval stage. Once this is fixed everything works back from it.</blockquote>

    Yes, but JSH specificaly states finished internal floor height.</blockquote>

    I have two restrictions (well, three if you include the roof pitch limit of not shallower than 40 deg). The first is for flood risk alleviation, recommended by the EA and applied by the planners as a condition, that sets the finished internal floor height, relative to Ordnance Datum. The second is a ridge height restriction, set by the planners on a recommendation from the AONB people, to maintain the relatively low profile of houses in the area, also relative to Ordnance Datum. Combined these two planning conditions give me 6.5 m between internal finished floor height and external roof ridge height.
   
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