Green Building Forum - Passive beam and block Sun, 08 Mar 2026 18:23:52 +0000 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Passive beam and block https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276838#Comment_276838 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276838#Comment_276838 Fri, 15 Nov 2019 08:17:26 +0000 craigcandrews Passive beam and block https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276844#Comment_276844 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276844#Comment_276844 Fri, 15 Nov 2019 09:53:51 +0000 Peter_in_Hungary 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.]]> Passive beam and block https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276847#Comment_276847 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276847#Comment_276847 Fri, 15 Nov 2019 11:22:44 +0000 gyrogear 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]]> Passive beam and block https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276852#Comment_276852 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276852#Comment_276852 Fri, 15 Nov 2019 15:48:45 +0000 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?

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?]]> Passive beam and block https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276854#Comment_276854 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276854#Comment_276854 Fri, 15 Nov 2019 16:30:09 +0000 tony Passive beam and block https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276866#Comment_276866 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276866#Comment_276866 Fri, 15 Nov 2019 23:56:20 +0000 djh Posted By: tonyin situ poured
in situ poured what?]]> Passive beam and block https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276873#Comment_276873 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276873#Comment_276873 Sat, 16 Nov 2019 07:58:06 +0000 Peter_in_Hungary 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.]]> Passive beam and block https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276881#Comment_276881 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276881#Comment_276881 Sat, 16 Nov 2019 14:19:19 +0000 tony Passive beam and block https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276923#Comment_276923 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276923#Comment_276923 Sun, 17 Nov 2019 21:06:31 +0000 Petlyn
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.]]> Passive beam and block https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276928#Comment_276928 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276928#Comment_276928 Mon, 18 Nov 2019 11:38:20 +0000 djh Passive beam and block https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276929#Comment_276929 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=16331&Focus=276929#Comment_276929 Mon, 18 Nov 2019 14:36:14 +0000 tony
Care should be taken in the case of ground gasses including radon]]>