"floating" wall

[Jim Walsh]

Hello all. My 1950s brick-built house has a light weight block wall, on the first floo r, separating the master bedroom from the bathroom. There is no correspondi ng wall, on the ground floor, underneath. A while back, when doing some work in the room below the bedroom and bathro om, 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 som eone must have built the block wall directly onto the floor boards; far fro m ideal, I would imagine, but it's been in place for quite a few years with out incident (though it is not original to the house). Recently, I had reason to remove the skirting board that runs along the wal l 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 flo or boards but are, in fact, fractionally aboove the floor boards. Does anyo ne have any idea what's going on here? To all intents and purposes, it appe ars that the wall is floating. The span is about 3m, so I would be surprise d if it could all hold in place just from being tied in to brick walls at e ither end. One notion that occurs to me is whether there could be a support ing steel for the lowermost course and that the blocks are shaped in some w ay that conceals it. Is this plausible? Are such techniques well-known? Suggestions appreciated. I'm reluctant to do too much exploratory excavatio n for fear of disrupting what might be a fragile structure! Thanks, Jim.

[John Rumm]

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

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?

[newshound]

separating the master bedroom from the bathroom. There is no corresponding wall, on the ground floor, underneath.

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).

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?

for fear of disrupting what might be a fragile structure!

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.

[Ericp]

separating the master bedroom from the bathroom. There is no corresponding wall, on the ground floor, underneath.

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).

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?

for fear of disrupting what might be a fragile structure!

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]

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]

oor, separating the master bedroom from the bathroom. There is no correspon ding wall, on the ground floor, underneath.

room, 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 s omeone must have built the block wall directly onto the floor boards; far f rom ideal, I would imagine, but it's been in place for quite a few years wi thout incident (though it is not original to the house).

all in question, in the bedroom. With the skirting removed, I can now see t he base of the wall and it appears that the blocks are not sitting on the f loor boards but are, in fact, fractionally aboove the floor boards. Does an yone have any idea what's going on here? To all intents and purposes, it ap pears that the wall is floating. The span is about 3m, so I would be surpri sed 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 suppo rting 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?

ion for fear of disrupting what might be a fragile structure!

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]

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?

[Tim Lamb]

In message , Jim Walsh 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.

[harry]

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

[george - dicegeorge]

separating the master bedroom from the bathroom. There is no corresponding wall, on the ground floor, underneath.

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).

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?

for fear of disrupting what might be a fragile structure!

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

[meow2222]

oor, separating the master bedroom from the bathroom. There is no correspon ding wall, on the ground floor, underneath.

room, 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 s omeone must have built the block wall directly onto the floor boards; far f rom ideal, I would imagine, but it's been in place for quite a few years wi thout incident (though it is not original to the house).

all in question, in the bedroom. With the skirting removed, I can now see t he base of the wall and it appears that the blocks are not sitting on the f loor boards but are, in fact, fractionally aboove the floor boards. Does an yone have any idea what's going on here? To all intents and purposes, it ap pears that the wall is floating. The span is about 3m, so I would be surpri sed 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 suppo rting 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?

ion for fear of disrupting what might be a fragile structure!

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 b reak up. Stop worrying.

NT