How many do you guess have been destroyed due to
defects? 10%? 20%? 50%? This is interesting. I
wonder whether NT will say anything... there
must be some information "out there" somewhere...


Its an interesting question. I doubt there is any source that could
tell us, since such stats are not afaik collected. Insurance companies
will have information about more recent failure rates, which they
likely wont disclose, but a century ago most owners had no insurance
and the housing stock was quite different to todays.

Theres another question too, that of the relationship between design
defects and maintenance. Some houses are deisgned to survive long
periods of neglect (eg concrete block), and some can't survive even
short periods of neglect (eg plastered straw). When failure occurs,
what do you blame it on, lack of maintenance or the design?

I also expect a lot of recorded failures would be down to lack of
maintenance.

Then theres the fact that demolition is probably more often decided on
the basis of multiple factors. Undesirable location, undesirable
housing type, in need of a fair amount of work, none of which in itself
threatens the houses's survival, and economic factors such as
redevelopment prospects.

Personal experience doesnt tell a lot either. I've seen very few houses
in a state of collapse, but then I dont know how many houses I've seen,
nor how many of the ones I've seen have serious defects that werent
noticed in what is often very brief observation. Also whatever defects
I've seen are over much less years than the average life expectancy of
housing.

Another point that I think affects the whole picture is to do with the
state of the Victorian housing market. A sizeable section of Vic
housing is now almost entirely missing. There were whole areas of towns
where housing was shacks, sheds, and other low cost shells. Few of
these remain. Presumably there were also intermediate buildings, eg
brick or wood frame houses as we know them today, but built to very a
basic standard, very small and so on. Most of these are also gone, so
if we assess the housing left today, we miss part of the picture.

There is also the fact that construction standards of the past varied
fairly widely, so to assess the survival of a particular type of
building technique one would need to classify all the house types when
examining any data. For example in a road one may see 2 storey
buildings splitting apart next to others in sound condition. Size of
foundations, wall construction, and other details all make a
difference. We only have limited data for a lot of buildings, it is
common for no-one to know what type or size of foundations a building
has, or even if it has none.

So not only do we lack records, it is also difficult to classify
buildings according to one reason for demise, and difficult to classify
each building acccording to foundation depth and so on.

My daily waffle budget is all used up, so to put it another way, how
could we know.


NT