"dennis@home" wrote in message
.uk...

http://www.astd60.dsl.pipex.com/UnderFloor.jpg

Difficult to judge the scale but that looks like a heck of a deep void.
Mine are only 4". I suppose it is dependent on the spans, my max is
~11ft in a 1930's house.

Are you sure its a house and not a bungalow that someone has converted the
attic?
4" is not deep enough for floor joists over 11' imho

Well 70 odd years must say something, that and the other identical 100 odd
houses built the same way.
Obviously building standards have come on some but I'd say it was adequate.
The one real design flaw is the cold bridge concrete sills downstairs.

--
Mike W