Chris Bacon wrote:
Mathew Newton wrote:
My Victorian (1905) terrace has a double skinned (not sure if it's got
a cavity as such, were they built like this?)

Sorry, missed that bit.

If it's 1905, it ain't Victorian, it's Edwardian.

Some of these old buildings did have "cavities", but very, very
few. Some examples date back to the late C.19th., but normally
"cavity walls" were not built at all, any "cavities" being only
by there accident of construction - "rat trap" construction as
used to cheapen construction (bricks laid on edge) is a good
example. If you've walls made of bricks laid with some going
right through the wall, others being laid along it (sorry for
the ultra-simplistic description!) then it is not a cavity wall,
although there may well be hollows in it due to incomplete
filling with mortar. Proper cavity walls only really became
generally used later.

Cavity walls were in the minority in Victorian times, but they were a
standard form of wall construction. They were used primarily in high
wind or wet climates, eg coastal regions. The advantage recognised was
that penetration of water into the outer leaf did not make the inner
leaf wet, and the outer leaf would dry out again before the inner
became damp. Only in the 1930s was the insulation benefit widely
appreciated, and only then did cavities become the norm.

Victorian cavity walls were not the uniform cavity walls we're used to
today. Vic houses typically used a variety of brick bonds. Half inch
cavities were common, often tied, often not. 4" bridged cavity ratbond
walls were also used, though not very common. And of course there is
also the random cavity stone wall, which dates back a very long way.


NT