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Floor Insulation/Slab Options

  • 04-05-2015 11:33am
    #1
    jiggins
    Registered Users, Registered Users 2 Posts: 33 ✭


    Hi all,

    I have 275mm left for insulation and finished floor slab in a new build. The house will have underfloor heating with a provisional BER of A2.
    To comply with BER I need 150mm PIR (U-value 1.1) with 125mm concrete slab. I would like to increase this if it would be worthwhile.

    The alternatives are:
    175mm PIR with 100mm Concrete slab (U-value 1.0) @ approx €1500 extra or
    200mm PIR with 75mm Concrete slab (U-value 0.9) @ probably double the extra cost.

    For comparison the walls will be 150mm Walltite (U-value 1.7 ish) and flat ceilings with approx 350mm mineral wool laid in two layers at right angles (will increase this most likely if budget allows.)

    So, thoughts and suggestions greatly appreciated,

    Jiggins.


Comments

  • #2
    BarneyMc
    Registered Users, Registered Users 2 Posts: 1,504 ✭✭✭BarneyMc


    If I were you I'd go with 200mm EPS and 75mm sand/cement slab. I think this would come in at around 0.11 U value. The insulation would be cheaper than PIR and 75mm sand/cement a good balance between heat retention and quick response.

    Don't forget to leave room for tiles/wooden floor, adhesive, etc. as well as space below external doors so they can open.

    I'm not in the business but that's my 2 cents worth.


  • #3
    ht9zni1gs28crp
    Closed Accounts Posts: 1,011 ✭✭✭ht9zni1gs28crp


    Im in agreement with what Barney says, the 200mm insulation is you safer bet, the two layers of 100mm are cross joint layed giving a lot more chance of a true U-Value reading across the whole floor.

    I have just recently done mine, although a 300mm build up to FFL. 200mm Insulation with 88mm screed onto which a 12mm tile sits.


  • #4
    Superdaddy
    Registered Users, Registered Users 2 Posts: 234 ✭✭Superdaddy


    I'd go along with what's been said already. But maybe consider 100mm PIR and 100mm eps to get a better u value.
    I looked at walltite for my house but it worked out twice the cost of cavity therm and the cavity therm has a much better u value of .12. Only downside is getting block layers to install it properly.
    Have you considered insulating the pitch of the roof instead?


  • #5
    galwaytt
    Registered Users, Registered Users 2 Posts: 12,823 ✭✭✭✭galwaytt


    ...2 x 100mm EPS or XPS would be my choice for floors. As a material it's more robust and impervious to damp or moisture.

    Ode To The Motorist

    “And my existence, while grotesque and incomprehensible to you, generates funds to the exchequer. You don't want to acknowledge that as truth because, deep down in places you don't talk about at the Green Party, you want me on that road, you need me on that road. We use words like freedom, enjoyment, sport and community. We use these words as the backbone of a life spent instilling those values in our families and loved ones. You use them as a punch line. I have neither the time nor the inclination to explain myself to a man who rises and sleeps under the tax revenue and the very freedom to spend it that I provide, and then questions the manner in which I provide it. I would rather you just said "thank you" and went on your way. Otherwise I suggest you pick up a bus pass and get the ********* ********* off the road” 



  • #6
    Hughbud
    Registered Users, Registered Users 2 Posts: 8 ✭Hughbud


    What do people think of the kore passive slab?


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  • #7
    Hughbud
    Registered Users, Registered Users 2 Posts: 8 ✭Hughbud


    Can normal insulation remove cold bridging? Rather than the expensive of the passive system I mentioned above?


  • #8
    Superdaddy
    Registered Users, Registered Users 2 Posts: 234 ✭✭Superdaddy


    Hughbud wrote: »
    What do people think of the kore passive slab?

    Used it on my house. Good job. Kingspan do the supergrund too.


  • #9
    Superdaddy
    Registered Users, Registered Users 2 Posts: 234 ✭✭Superdaddy


    Hughbud wrote: »
    Can normal insulation remove cold bridging? Rather than the expensive of the passive system I mentioned above?

    What is normal? Polystyrene or EPS is pretty standard. It's the design that is critical for removing cold bridging.


  • #10
    Hughbud
    Registered Users, Registered Users 2 Posts: 8 ✭Hughbud


    Seems to cost twice that of standard insulation?


  • #11
    ht9zni1gs28crp
    Closed Accounts Posts: 1,011 ✭✭✭ht9zni1gs28crp


    What is the Kore Passive Slab offering that cant be achieved with standard materials?

    You will still need to detail out all the cold bridges for both products.....


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  • #12
    sydthebeat
    Subscribers Posts: 42,172 ✭✭✭✭sydthebeat


    miller_63 wrote: »
    What is the Kore Passive Slab offering that cant be achieved with standard materials?

    You will still need to detail out all the cold bridges for both products.....

    have you seen the system?
    the foundation cold bridge is "detailed out" in its design

    'standard' materials usually incur a thermal bridge, even AAC blocks dont significantly reduce the flow.
    you could use something like a foamglas block, but then, these wouldnt be 'standard' materials


  • #13
    hexosan
    Registered Users, Registered Users 2 Posts: 1,740 ✭✭✭hexosan


    Plus Foamglas blocks are about €22 each


  • #14
    galwaytt
    Registered Users, Registered Users 2 Posts: 12,823 ✭✭✭✭galwaytt


    Hughbud wrote: »
    Can normal insulation remove cold bridging? Rather than the expensive of the passive system I mentioned above?
    Hughbud wrote: »
    Seems to cost twice that of standard insulation?

    What are you calling 'normal' ?

    EPS and XPS are entirely 'normal' for such applications.

    Ode To The Motorist

    “And my existence, while grotesque and incomprehensible to you, generates funds to the exchequer. You don't want to acknowledge that as truth because, deep down in places you don't talk about at the Green Party, you want me on that road, you need me on that road. We use words like freedom, enjoyment, sport and community. We use these words as the backbone of a life spent instilling those values in our families and loved ones. You use them as a punch line. I have neither the time nor the inclination to explain myself to a man who rises and sleeps under the tax revenue and the very freedom to spend it that I provide, and then questions the manner in which I provide it. I would rather you just said "thank you" and went on your way. Otherwise I suggest you pick up a bus pass and get the ********* ********* off the road” 



  • #15
    ht9zni1gs28crp
    Closed Accounts Posts: 1,011 ✭✭✭ht9zni1gs28crp


    sydthebeat wrote: »
    have you seen the system?
    the foundation cold bridge is "detailed out" in its design

    'standard' materials usually incur a thermal bridge, even AAC blocks dont significantly reduce the flow.
    you could use something like a foamglas block, but then, these wouldnt be 'standard' materials

    It begs the question then why is the OP asking the question he is if he is going the Passive Route? Surely this would all have been design and set out.

    If not then why is it being considered? Probably explains my questioning/reasoning a bit better. smile.png


  • #16
    sydthebeat
    Subscribers Posts: 42,172 ✭✭✭✭sydthebeat


    miller_63 wrote: »
    It begs the question then why is the OP asking the question he is if he is going the Passive Route? Surely this would all have been design and set out.

    If not then why is it being considered? Probably explains my questioning/reasoning a bit better. smile.png

    i think hughbud is simply asking can 'standard' materials do the job of a passive foundation system.

    and the answer is....
    if you are going the passive route, ask your passive adviser
    if not... no, standard materials and practises dont so the same job.
    you can limit the bridge as much as your budget will allow... ask your technical advisor because everything has knock on effects.


  • #17
    galwaytt
    Registered Users, Registered Users 2 Posts: 12,823 ✭✭✭✭galwaytt


    miller_63 wrote: »
    What is the Kore Passive Slab offering that cant be achieved with standard materials?

    You will still need to detail out all the cold bridges for both products.....

    Exactly.

    Kore uses standard 300kPa EPS - it's the detailing that makes the difference. This applies to all builds.

    Ode To The Motorist

    “And my existence, while grotesque and incomprehensible to you, generates funds to the exchequer. You don't want to acknowledge that as truth because, deep down in places you don't talk about at the Green Party, you want me on that road, you need me on that road. We use words like freedom, enjoyment, sport and community. We use these words as the backbone of a life spent instilling those values in our families and loved ones. You use them as a punch line. I have neither the time nor the inclination to explain myself to a man who rises and sleeps under the tax revenue and the very freedom to spend it that I provide, and then questions the manner in which I provide it. I would rather you just said "thank you" and went on your way. Otherwise I suggest you pick up a bus pass and get the ********* ********* off the road” 



  • #18
    Hughbud
    Registered Users, Registered Users 2 Posts: 8 ✭Hughbud


    Hi I asked as I want to have passive elements just not the badge and wondered if standard materials used correctly can achieve the same result or v close to it


  • #19
    Superdaddy
    Registered Users, Registered Users 2 Posts: 234 ✭✭Superdaddy


    The L shaped EPS 300 which makes up the cold bridge elimating design and is load bearing, carrying the weight of the house is what makes it expensive. The EPS 100 sheets making up the rest of the raft is relatively inexpensive. This is normal slab insulating material but is not recommend for load bearing. So can you eliminate all cold bridging with just EPS 100? I would say no. I'm not an engineer but I could send you the drawing for my kore raft.


  • #20
    galwaytt
    Registered Users, Registered Users 2 Posts: 12,823 ✭✭✭✭galwaytt


    Superdaddy wrote: »
    The L shaped EPS 300 which makes up the cold bridge elimating design and is load bearing, carrying the weight of the house is what makes it expensive. The EPS 100 sheets making up the rest of the raft is relatively inexpensive. This is normal slab insulating material but is not recommend for load bearing. So can you eliminate all cold bridging with just EPS 100? I would say no. I'm not an engineer but I could send you the drawing for my kore raft.

    Bear in mind as you progress up the densities from EPS100 to EPS300, like all insulations, u-value decreases. There are no omelettes without breaking eggs. Use the density that suffices, no point in any more.

    The road in the Shannon tunnel is laid on XPS300.

    Ode To The Motorist

    “And my existence, while grotesque and incomprehensible to you, generates funds to the exchequer. You don't want to acknowledge that as truth because, deep down in places you don't talk about at the Green Party, you want me on that road, you need me on that road. We use words like freedom, enjoyment, sport and community. We use these words as the backbone of a life spent instilling those values in our families and loved ones. You use them as a punch line. I have neither the time nor the inclination to explain myself to a man who rises and sleeps under the tax revenue and the very freedom to spend it that I provide, and then questions the manner in which I provide it. I would rather you just said "thank you" and went on your way. Otherwise I suggest you pick up a bus pass and get the ********* ********* off the road” 



  • #21
    BryanF
    Moderators, Home & Garden Moderators Posts: 10,146 Mod ✭✭✭✭BryanF


    Hughbud wrote: »
    Hi I asked as I want to have passive elements just not the badge and wondered if standard materials used correctly can achieve the same result or v close to it
    neither close nor the same.

    who will design, calculate, spec, detail all interfaces and model heat gains & losses? Who will ensure all components are installed together correctly? The point of certification is to ensure all intentions get translated to site. without this you're just another 'ah sure maybe it'll be close to'


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  • #22
    galwaytt
    Registered Users, Registered Users 2 Posts: 12,823 ✭✭✭✭galwaytt


    BryanF wrote: »
    neither close nor the same.

    who will design, calculate, spec, detail all interfaces and model heat gains & losses? Who will ensure all components are installed together correctly? The point of certification is to ensure all intentions get translated to site. without this you're just another 'ah sure maybe it'll be close to'

    I think you're being a bit harsh there tbh.....It's quite possible to build to a high standard "without the badge" without over complicating it. There are people out the who would model individual things for you if you are interested.

    Ode To The Motorist

    “And my existence, while grotesque and incomprehensible to you, generates funds to the exchequer. You don't want to acknowledge that as truth because, deep down in places you don't talk about at the Green Party, you want me on that road, you need me on that road. We use words like freedom, enjoyment, sport and community. We use these words as the backbone of a life spent instilling those values in our families and loved ones. You use them as a punch line. I have neither the time nor the inclination to explain myself to a man who rises and sleeps under the tax revenue and the very freedom to spend it that I provide, and then questions the manner in which I provide it. I would rather you just said "thank you" and went on your way. Otherwise I suggest you pick up a bus pass and get the ********* ********* off the road” 



  • #23
    BryanF
    Moderators, Home & Garden Moderators Posts: 10,146 Mod ✭✭✭✭BryanF


    galwaytt wrote: »
    I think you're being a bit harsh there tbh.....It's quite possible to build to a high standard "without the badge" without over complicating it. There are people out the who would model individual things for you if you are interested.
    Perhaps I got side tracked, what I was getting at is the 'used correctly' comment, my point being how do you ensure the materials are used/ integrated correctly?
    I think we can both point to countless threads where details have not been properly considered, air-tightness is an after thought, mould is growing in new houses etc etc.

    Yes you can build to a high standard without the badge, but close to passive, or built with passive components, just aint 'passive' - just my personal opinion.

    There is still massive gap in knowledge of passive: mech systems, Heat gains, thermal continuity & air-tightness, in the contractor/installer sphere.

    Anyway, I'll say no more to drag this of topic any further.


  • #24
    ht9zni1gs28crp
    Closed Accounts Posts: 1,011 ✭✭✭ht9zni1gs28crp


    BryanF wrote: »

    Yes you can build to a high standard without the badge, but close to passive, or built with passive components, just aint 'passive' - just my personal opinion.

    There is still massive gap in knowledge of passive: mech systems, Heat gains, thermal continuity & air-tightness, in the contractor/installer sphere.

    Anyway, I'll say no more to drag this of topic any further.

    This is it in a nutshell, as someone who is building to certification I am getting entirely fed up of the phrase 'near passive' The difference in the whole package performing as one rather than a detail being driven by a product sales guy.

    Its the equivalent of me advertising a Ford Escort for sale and describing it as 'nearly a BMW' just as its got four doors, an engine and four wheels redface.png

    You either build to the standard regs or you build to certification levels. Both are miles apart.


  • #25
    jiggins
    Registered Users, Registered Users 2 Posts: 33 ✭jiggins


    Thanks to all for the replies! I will investigate all the proposed options. Thanks again, jiggins.


  • #26
    Elsie161211
    Registered Users, Registered Users 2 Posts: 19 ✭Elsie161211


    Superdaddy wrote: »
    The L shaped EPS 300 which makes up the cold bridge elimating design and is load bearing, carrying the weight of the house is what makes it expensive. The EPS 100 sheets making up the rest of the raft is relatively inexpensive. This is normal slab insulating material but is not recommend for load bearing. So can you eliminate all cold bridging with just EPS 100? I would say no. I'm not an engineer but I could send you the drawing for my kore raft.

    Hi,

    I am starting to build in the coming months and my engineer has decided that we need a raft foundation. I am not going for a passive house but we were chatting about the Kore Passive slab as an option the other day and I am trying to figure out is it worth the extra expensive considering I am not going for a full passive house. The only reason for installing it would be for the thermal bridge solution and the gain from this. I would really like to see your drawing please


  • #27
    siralan
    Registered Users, Registered Users 2 Posts: 80 ✭✭siralan


    Did you use the Kore system in the end? Just wondering if it worked out to be cost effective? Im looking at it as part of a raft foundation which will then take a precast rapid build concrete structure?


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