"floating" wall

[Jim Walsh]

Hello all.
My 1950s brick-built house has a light weight block wall, on the first floor, separating the master bedroom from the bathroom. There is no corresponding wall, on the ground floor, underneath.
A while back, when doing some work in the room below the bedroom and bathroom, I made a hole in the ceiling to see how the wall above was supported. I expected to find an RSJ or beam, but there was nothing. I guessed that someone must have built the block wall directly onto the floor boards; far from ideal, I would imagine, but it's been in place for quite a few years without incident (though it is not original to the house).
Recently, I had reason to remove the skirting board that runs along the wall in question, in the bedroom. With the skirting removed, I can now see the base of the wall and it appears that the blocks are not sitting on the floor boards but are, in fact, fractionally aboove the floor boards. Does anyone have any idea what's going on here? To all intents and purposes, it appears that the wall is floating. The span is about 3m, so I would be surprised if it could all hold in place just from being tied in to brick walls at either end. One notion that occurs to me is whether there could be a supporting steel for the lowermost course and that the blocks are shaped in some way that conceals it. Is this plausible? Are such techniques well-known?
Suggestions appreciated. I'm reluctant to do too much exploratory excavation for fear of disrupting what might be a fragile structure!
Thanks, Jim.

[John Rumm]

On 22/03/2013 21:36, Jim Walsh wrote:

> Hello all. My 1950s brick-built house has a light weight block wall,
> on the first floor, separating the master bedroom from the bathroom.
> There is no corresponding wall, on the ground floor, underneath. A
> while back, when doing some work in the room below the bedroom and
> bathroom, I made a hole in the ceiling to see how the wall above was
> supported. I expected to find an RSJ or beam, but there was nothing.
> I guessed that someone must have built the block wall directly onto
> the floor boards; far from ideal, I would imagine, but it's been in

Its quite common with light weight walls... especially when running
across the joists.

> place for quite a few years without incident (though it is not
> original to the house). Recently, I had reason to remove the skirting
> board that runs along the wall in question, in the bedroom. With the
> skirting removed, I can now see the base of the wall and it appears
> that the blocks are not sitting on the floor boards but are, in fact,
> fractionally aboove the floor boards. Does anyone have any idea
> what's going on here? To all intents and purposes, it appears that
> the wall is floating. The span is about 3m, so I would be surprised
> if it could all hold in place just from being tied in to brick walls
> at either end. One notion that occurs to me is whether there could be
> a supporting steel for the lowermost course and that the blocks are
> shaped in some way that conceals it. Is this plausible? Are such
> techniques well-known? Suggestions appreciated. I'm reluctant to do
> too much exploratory excavation for fear of disrupting what might be
> a fragile structure! Thanks, Jim.

Can you actually see under it, or could it simply be there is a bed of
mortar under it that means the blocks are spaced off the floor level a
little?




--
Cheers,

John.

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[newshound]

On 22/03/2013 21:36, Jim Walsh wrote:

I don't suppose you have actually slid (say) a steel rule under the full
width of the blockwork and all along the length of the wall, to prove
that there are no contacts at all with the floor structure. I'd be
surprised if there was a "hidden" steel beam. You don't need very much
support along the length to keep a light block wall stable.

--
For every complex problem, there is a solution which is simple, neat,
and wrong.
H L Menken

[Ericp]

All the upper walls in my 1979 house are like this, none are over a
lower wall.

They are a very thin thermalite/breeze block on top of a wooden beam
and plastered.

If I put a socket back box in one room, the back is in the other
bedroom, a right pain. :(

[Bill Wright]

Jim Walsh wrote:
> Hello all.

The bedroom walls in the 1948 council house where I grew up are like
that. There is a clear gap under the wall and as a child I used to use
it to run wires about.
In my present 1960s house some upstairs walls are like that.

Bill

[harry]

It was common practice years ago. The blocks will likely be proper
breeze blocks, ie made out of power station fused ash & very light..
The gap under is probably due to the timber warping/shrinking as it
dried out.
So long as there are no cracks/other visible damage, leave alone.

[polygonum]

On 23/03/2013 07:42, harry wrote:
<>
> It was common practice years ago. The blocks will likely be proper
> breeze blocks, ie made out of power station fused ash & very light..
> The gap under is probably due to the timber warping/shrinking as it
> dried out.
> So long as there are no cracks/other visible damage, leave alone.
>

And I thought that lightweight concrete block such as Thermalite were
significantly lighter than breeze? I always think of them as being a bit
lighter than the heavy concrete blocks, but much heavier than
lightweight blocks.

Anyone care to confirm - or otherwise?

--
Rod

[Tim Lamb]

In message <3c43ef83-1c07-4c3c...@googlegroups.com>, Jim
Walsh <jimwal...@gmail.com> writes

You can create a *hidden* beam by using strips of expanded metal in two
or more of the lower courses. Sounds unlikely here from what others have
said.

--
Tim Lamb

[harry]

There are various grades. The better the insulation value the lighter
they are. And weaker.

[george - dicegeorge]

i'd look in the attic to check that its
not holding up any important roof beams!
[g]

[meow...@care2.com]

Unsupported walls work on the same principle as soldier courses. There are lots of them about in odl properties, and they only occasionally slip and break up. Stop worrying.


NT