I'm trying to date some work on a house (c1920), specifically a dividing
wall in the attic space between two semis.
It's been made of quite new-looking aerated blocks - the ones with the
zig-zag scribe marks on the side.
What's the oldest that they could possibly be? To the nearest decade,
I've seen those used in 70s buildings for sure.
Wiki sez this:
The history of foam concrete dates back to the early 1920s and the
production of autoclaved aerated concrete, which was used mainly as
insulation. A detailed study concerning the composition, physical
properties and production of foamed concrete was first carried out in
the 1950s and 60s. Following this research, new admixtures were
developed in the late 1970s and early 80s, which led to the commercial
use of foamed concrete in construction projects. Initially, it was used
in the Netherlands for filling voids and for ground stabilisation.
Further research carried out in the Netherlands helped bring about the
more widespread use of foam concrete as a building material.
So I reckon that what that is is not the 1920s stuff, but the late
70s/80s onwards stuff.
Canada is all right really, though not for the whole weekend.
Aerated concrete and ash blocks have been around since the 1950s, a
house I lived in built in the 50s had them.
There are other types, which may be later/earlier.
Of course, assuming they are the 1950s type, the work could be much later.
I believe, at one time, it wasn't unknown for there to be no dividing
walls in some roof spaces, or for them to be incomplete.
The true "lightweight" blocks are made from PFA. or pulverated fuel ash
as produced by "modern" coal fired stations where coal is "milled" into
a very fine powder in large ball or roller mills before being blown into
the boilers using something not unlike an oil or gas burner. IIRC it was
normally ignited by oil burners. Kingston upon Thames, opened in 1948,
must have been one of the last "chain grate" stations in the UK. As the
name suggests, "bulk" coal is burned on a moving grate.
I think Croyden B, from about the same period, used Pulverised Fuel.
PFA is collected from the electrostatic precipitators and washed into
lagoons where it settles. It would first have been available in large
quantities from the 1950's but I think it started being exploited more
seriously in the 1960's.
Amazingly, according to Wikipedia, the US trialed PF burning in 1918.
The dash for gas, solar and wind is going to muck up the building
industry at some point then.
Maybe the luddite UK building trades will drag themselves kicking
and screaming into the modern era and use SIPP panels with cladding
like they do in many other countries.
Our first house built in the early seventies had breeze blocks for some int
ernal walls however a neighbour got hold of some concrete blocks that appea
red to be constructed with wood chips mixed in which as soon as they got we
t just seem to disintegrate of course the fool built a garden wall then won
dered why it fell down. I have never seen anything like them since.
On Sunday, 9 September 2018 22:15:40 UTC+1, Tricky Dicky wrote:
nternal walls however a neighbour got hold of some concrete blocks that app
eared to be constructed with wood chips mixed in which as soon as they got
wet just seem to disintegrate of course the fool built a garden wall then w
ondered why it fell down. I have never seen anything like them since.
Presumably if the woodchips are soaked before casting the blocks would then
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