Home  5  Books  5  GBEzine  5  News  5  HelpDesk  5  Register  5  GreenBuilding.co.uk
Not signed in (Sign In)

Categories



Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.
Buy individually or both books together. Delivery is free!


powered by Surfing Waves




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: Passive beam and block

Bottom of Page

1 to 11 of 11

  1.  
  1.  
    Having the ground investigation report confirm a piled foundation solution will be advisable, I am now forced into providing beam and block suspended floor for my solid wall EWI passive House. I was hoping an insulated slab would work, but led to believe a slab isn't possible inside the ringbeam (unstable ground) So, any guidance on thermally breaking or reducing the losses through a beam and block floor into the foundation beam? Marmox thermablocks, airated blocks below dpc? And how far down below dpc is it best for the ewi to add benefits.
  2.  
    I don't see why you can't treat the beam and block like an insulated slab. OK so the beam and block can sit on / in the ring beam but there would be nothing to stop you insulating under the beam and block as if it were a slab, just you might have to foam between the (EPS?) insulation and the floor to ensure that it is fully effective.
    An alternative solution would be to use a reinforced concrete raft linked into the ring beam and using the insulation as the below shuttering the same as you would for a slab. Its all about choice and costs.
    • CommentAuthorgyrogear
    • CommentTimeNov 15th 2019
     
    Posted By: craigcandrewsled to believe a slab isn't possible inside the ringbeam (unstable ground)


    Well, use micropiles in this area (? cost...) and then slab over pile cappings.

    Or suspended slab like PiH says, but rather than insulate the slab soffit, insulate the periphery walls, and use the ground for AGS thermal energy storage or PAHS etc...

    gg
    •  
      CommentAuthordjh
    • CommentTimeNov 15th 2019
     
    Posted By: Peter_in_HungaryI don't see why you can't treat the beam and block like an insulated slab. OK so the beam and block can sit on / in the ring beam but there would be nothing to stop you insulating under the beam and block as if it were a slab, just you might have to foam between the (EPS?) insulation and the floor to ensure that it is fully effective.

    Because the piles act as big thermal bridges?

    Is the ground just unstable (i.e. made up ground that has very low load-bearing capacity and is liable to drop over time) or is it liable to heave as well?

    Alternatives I can think of:
    (1) put a steel ring on the top of the piles and use them to support a suspended timber floor (I don't know any details, see http://www.passivhaustrust.org.uk/UserFiles/File/Projects/PassivClass%20BV2.pdf for an example)
    (2) if you want to use beam-and-block then you're effectively in insulate-on-top territory, which is AWm05-EFo01 in the Passivhaus Details book, so apart from some thermal break blocks at the base of the walls the main thing it says to worry about would be moisture and condensation paths (see p32 in the book). You should also put some insulation underneath the beam and block AIUI - maybe one of the proprietary insulated beam-and-block systems would be usable.
    (3) you could build a raft on the top of the piles and use that as the oversite to then build a passive slab on top.

    It seems like a time when it would be worth seeking out an architect and engineer both with specific experience of building a passivhaus on unstable ground. Maybe ask RIBA and IStructE?
    • CommentAuthortony
    • CommentTimeNov 15th 2019
     
    I would avoid beam and block and choose concrete planks, failing that in situ poured
    •  
      CommentAuthordjh
    • CommentTimeNov 15th 2019
     
    Posted By: tonyin situ poured

    in situ poured what?
  7.  
    Posted By: djh
    Posted By: Peter_in_HungaryI don't see why you can't treat the beam and block like an insulated slab. OK so the beam and block can sit on / in the ring beam but there would be nothing to stop you insulating under the beam and block as if it were a slab, just you might have to foam between the (EPS?) insulation and the floor to ensure that it is fully effective.

    Because the piles act as big thermal bridges?

    I see the point about the cold bridge of the piles.
    Then put a reinforced slab + integrated ring beam on top of the piles then insulation and screed and build of that in single skin block and EWI with 300 grade EPS under the wall areas and the slab insulation joining up with the EWI (there may be a need for a second ring beam between the slab insulation and the block wall) If the ground is subject to heave then something sacrificial would be needed under the slab area that would deform in the event of heave but would support the pouring of the slab (time to consult a SE) IMO a slab on the ground would be preferable to a suspended floor.

    Posted By: djh
    Posted By: tonyin situ poured

    in situ poured what?

    Concrete. - Ring beam and slab. If a reinforced slab is used then both poured as one. If beam and block is used then the beams ends should be included into the ring beam - at least that is what they do here.
    • CommentAuthortony
    • CommentTimeNov 16th 2019
     
    Insitu poured concrete slab, bearing on inside skin, no air leakage, unlike b&b
    • CommentAuthorPetlyn
    • CommentTimeNov 17th 2019
     
    There seems to be general agreement that you can bring the beam and block floor into the warm space by insulating the void beneath to the underside of the floor.

    Our building control told us that if there was any airspace between the insulation and the suspended floor, ventilation would need to be provided and so it was important to ensure that the void was filled completely and that no settlement could occur.

    In the circumstances we chose expanded glass with high compressive strength and in bead form, of spherical nature, giving a non-combustible, free-flowing, durable insulation that would last the life of the building.
    •  
      CommentAuthordjh
    • CommentTimeNov 18th 2019
     
    In the OPs circumstances, the compressive strength of any insulation under the floor is probably pretty much irrelevant. If the ground is unstable, the most likely future scenario will be that it drops away, and there might be the possibility of heave that would break anything except a raft. So tying the insulation to the underside of the floor and including crushable material if heave is a possibility are the important points, I think.
    • CommentAuthortony
    • CommentTimeNov 18th 2019
     
    Yes, eps beads might be best,

    Care should be taken in the case of ground gasses including radon

1 to 11 of 11

  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