Home  5  Books  5  Magazines  5  News  5  GreenPro  5  HelpDesk  5  Your Cart  5  Register  5  Green Living Forum
Not signed in (Sign In)

Categories



 



Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
 Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.




Housing - New Build: EPS grades

Bottom of Page

1 to 15 of 15

  1.  
    • CommentAuthorgrumpy
    • CommentTimeSep 21st 2012 edited
     
    Hello an02ew (or anyone else reading this): have you come across a completely flat reinforced slab on EPS, by experience or hearsay? That is, like the Isoquick prefabricated system, but self-constructed. If so, I'm interested to know the EPS density specified by the engineer.

    I have looked at the relevant BS 13163 for EPS. The grade used for Isoquick (BASF Peripor) is higher than EPS300, and has a design load (2% creep over 50 years) of 100 kN/m² (10 tonnes per m²).

    This seems overspecified for domestic use. I think the BRE reckons a typical house has loadings no higher than 30 kN/m² (3 tonnes per m²), and that’s for up to three-storey masonry town houses. A one- and two-storey timber frame should be a lot less. According to the BS, this is achieved with EPS100; that is, for EPS100, the design load for expected creep deformation of 2% over 50 years is 30 kN/m².

    I came across this thread but it doesn't really answer the question:

    http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8419&page=2

    As someone implies there, the lack of experience of and interest in full-foundation EPS in the UK explains the lack of confidence by engineers and the lack of interest by manufacturers.

    Thanks again.
    • CommentAuthoran02ew
    • CommentTimeSep 21st 2012
     
    Posted By: grumpyHello an02ew


    Hi

    i also looked into Isoquick for my job, however i found them expensive and a bit of a closed shop, so i came up with my own idea, and yes i did post detail in the above link, the EPS shutter only has to support conc until its set, so compressive strength of EPS isn’t really an issue.
    • CommentAuthorgrumpy
    • CommentTimeSep 21st 2012
     
    Hi -Thanks.

    Yes, no problem with the upstand/shutter, which takes little or no load and can be EPS70.

    I'm referring to the grade of the EPS under the slab. In Isoquick, the slab is fully flat, with no edge thickenings, no piles etc. The extra reinforcement zones are designed within the uniform slab thickness. I think all the other proprietary systems have edge beams resting on EPS, e.g. Groundshield, Viking, Insulslab, but for a middling house the load would not be much greater under those beams than under the Isoquick flat slab, so the grade of EPS should be similar. I'm just puzzled as to why such dense EPS is thought to be necessary for these applications.
    • CommentAuthoran02ew
    • CommentTimeSep 21st 2012
     
    82m2 for about £6000 plus engineers cals plus vat, plus all ground works ,re-inforcing and concrete

    we went for a self designed system based on insulated piles supporting a fully insulated re-inforced slab. see

    http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=9308e
  5.  
    Hi Grumpy, have had a look at our "Passive Slab"? http://www.viking-house.co.uk/passive-slab-insulated-foundations.html
  6.  
    I have Isoquick 300mm insulated foundations with a 200mm reinforced concrete slab. Isoquick is well designed and very easy to lay but I think it is feasible to DIY, it would just take a bit more thought and effort with the upstand.
    • CommentAuthorgrumpy
    • CommentTimeSep 22nd 2012 edited
     
    Thanks for your comments.

    an02ew - your foundation build is impressive. It will be a challenge for us if we try it! And we need levels to satisfy a timber frame manufacturer, probably +/- 3 mm.

    Peter - we do like the idea of Isoquick. It looks well engineered and very accurate, and it needs no shuttering. But when we enquired, we found: it's quite expensive, it has to be transported from Germany, and it has to be fitted by a visiting team from the west country, which is far from us (a local groundworks team can do everything else). Is all that correct?

    And Peter - about the thickness of the slab. Did you use a local engineer? And what is your ground like? We have clay starting at 600 mm down. Worse than that: we have massive poplars within range - the nastiest of all trees. So our engineer came down at 350 mm for the slab. This is independent of whatever goes under the slab.

    Further contributions welcome - still including any from anyone who has used EPS to support load, and what grade EPS that was.
    • CommentAuthoran02ew
    • CommentTimeSep 22nd 2012
     
    Posted By: PeterStarckI think it is feasible to DIY,

    i thought the same thing and looked into it in some depth, however the real nifty part of the Isoquick system is the way each block locks together to eliminate all cold bridge impossible to recreate on a DIY level.



    Posted By: grumpyan02ew - your foundation build is impressive. It will be a challenge for us if we try it! And we need levels to satisfy a timber frame manufacturer, probably +/- 3 mm.


    Our slab is with 10-15mm over the 12M length of slab and within 5mm level over 82m2, we also have used timber frame with a EWI system meeting the EPS ground shutter coming up out of the ground our EWI is 200mm thick and EPS ground shutter is 300mm thick, over these thicknesses the 10-15mm deviation should make little difference
  9.  
    Grumpy, we are on light clay with the water table 2.5m down in running sand. Based on the soil tests we were told we needed 250mm compacted type 1 sub base with 50mm compacted granite fines on top. Then there is the 300mm polystyrene and the 200mm reinforced concrete slab. The calculations also took into account the position of the nearest trees which are a willow, lime and two silver birches which are around 15m away.

    When we had ours laid over two years ago, we were the first in the country, there was only one installer in England but I've spoken to the German Isoquick rep at Ecobuild since and was told there are now more installers.

    It is expensive but at the time the only alternative was the Scandinavian Foundations company which after speaking to them we weren't comfortable using.

    An02ew, I would have thought it possible to glue 200mm upstands to the base polystyrene and reinforce the outside of the upstands until the concrete had set.
    • CommentAuthorgrumpy
    • CommentTimeSep 23rd 2012 edited
     
    Peter - what roughly are your raft lengths and overall area?

    Based on his earlier posts, I think an02ew did do as you suggest - he will confirm. It could be done other ways too, e.g.

    (1) Shutter to full height at just the raft dimensions; lay the base EPS inside; pour; glue the upstand EPS to the whole flush side of base EPS and raft (DPM).
    (2) Shutter to full height at outer insulation dimensions; lay both base and upstand EPS inside, interlocked how you like at the edge; pour.
    (3) Lay the base EPS to full insulation dimensions; shutter on top of the base EPS, with shuttering stepped inwards by the perimeter EPS thickness; pour; glue the upstand EPS horizontally to the base projection and vertically to the raft edge.

    If you're working with a third-party groundworker, the choice presumably would also depend on how they think they can get the best result - in terms of raft levels/dimensions as well as thermal barrier quality.

    I would be interested in an02ew's comments on these options.

    Also, for options (1) and (3), how is EPS best glued to the DPM on the side of the raft? Glueing EPS to EPS is fairly well covered elsewhere on GBF.

    On this US link there are a couple of short videos related to this (towards the bottom). I can see ply shuttering with an EPS base inside, and the perimeter application looks like option (1) above.

    http://www.naturalhomeandgarden.com/blogs/blog.aspx?blogid=3180&tag=sonya%20newenhouse
  11.  
    Grumpy, the overall area is 90.5m2 and the shape is roughly an L, 10m x 9.5m, with a couple of rectangular areas added.
    • CommentAuthoran02ew
    • CommentTimeSep 24th 2012
     
    Grumpy. i think your tolerances over that area with what sounds like a very irregular shape are too stringent +-3mm working with concrete a strong and unforgiving substance(a cruel mistress)is unreasonable.

    Posted By: grumpy(1) Shutter to full height at just the raft dimensions; lay the base EPS inside; pour; glue the upstand EPS to the whole flush side of base EPS and raft (DPM).

    i would have thought stopping the concrete running under timber shutter hard work.

    Posted By: grumpyShutter to full height at outer insulation dimensions; lay both base and upstand EPS inside, interlocked how you like at the edge; pour.


    Most timber shutters use stone as strong backs to shutter all you have done is add another element to the side shutter, may be useful to fix 4x2 and support back along ground?

    Posted By: grumpyLay the base EPS to full insulation dimensions; shutter on top of the base EPS, with shuttering stepped inwards by the perimeter EPS thickness; pour; glue the upstand EPS horizontally to the base projection and vertically to the raft edge.


    see response to 1
  13.  
    Hi Grumpy, we work to a 2mm tolerance when we build insulated foundations for our Passive Houses. We use EPS100 and EPS300, EPS300 has a design load of 120kN/m2 and EPS100 has a design load of 40kN/m2. We've built over 200 insulated foundations to date.
      D.Matthews.JPG
  14.  
    Hi Viking House, just as a matter of interest is your system based on or linked in some way to Scandinavian Foundations that used to exist, it looks similar.
    • CommentAuthoran02ew
    • CommentTimeSep 25th 2012
     
    very impressive VH, however i cannot see how or even why you would need to work to that level of accuracy 2mm is little more than a pencil line. Surly a more flexible system could speed up the process. When concrete is poured your shutter must move more than 2mm given the nature of concrete. Having said that I do like to see vast amount of EPS in the ground ready for concrete, it reminds me of an M.C. Escher

1 to 15 of 15

  1.  
Add your comments

    Username Password
  • Format comments as
 
Back to Discussions Top of Page
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press