10-12 years ago I packed out the gaps which had developed between the
sleeper walls on top of the concrete float and the joists supporting our
timber kitchen floor (1920s semi, North London). The floor had become bouncy
again and with new kitchen units en route and some electrics needing
attention, it was time today to rip it up again. I found some small gaps
from extra settlement over the intervening years, but no more than you'd
expect. But the real problem appears to be around the boiler alcove in the
middle of one wall - presumably once a fireplace. This is an area I didn't
even look at when packing the joists before. There seems to be a brick
sleeper-type wall built out around the former fireplace area. The middle of
it seems to be full of old builders' rubble into which I can poke a stick
for a long way but there is a concrete shelf above - thankfully sound as far
as I can see - supporting the boiler. As you can see from this pic:

http://www.justigator.pwp.blueyonder.../DSC00681a.jpg

three of the joists are supposed to rest on the wall top but the wall has
settled and a gap has opened up (there was also originally a length of joist
timber along the concrete edge at right angles to the joists which was
completely rotten and providing no support). To judge from the amount of
curve in the floorboards, the joists have dropped some 20mm and are now not
properly supported at their ends - although they are at the sleeper wall in
front (packing shown is undisturbed from last time). It may not be clear
from the photo but the top of the problem wall has a pronounced lean towards
the camera - enough to make me unwilling to just put more packing under and
seal up again, for fear of it just collapsing under the extra weight.

The local BCO won't visit to advise and it's next to impossible to get a
builder round here these days for this sort of thing. So I'm planning to
build a new sort of mega-sleeper wall between the one in the foreground and
the problem wall, filling in the whole intervening area to try to both
provide support for the floor and prevent any further sliding out forwards
of the fireplace support wall. I don't forsee any problem with ventilation -
there is plenty down there and I will leave gaps.

Does anyone have any tips or suggestions please? TIA.


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RRH

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