Rogues Gallery
These
pictures show the tops of some very large chimneystacks. The white
stuff looks a bit like snow but in fact it’s cement rendering.
The installers have been faced with the difficulty — or impossibility
— of putting a chimney lashing kit around a really big stack.
To do this it is necessary to reach to all four corners of the chimney.
If the roof is steep the outer edges of the stack can be well out
of reach. Another problem is that a very long lashing wire has so
much stretch in it that it can never be properly tightened. Chimney
lashing kits are not intended for big stacks with dozens of pots.
None of this provides these installers with an adequate excuse.
Fixing chimney kits to pots is very dangerous. Chimney brackets
are designed to fit securely on a 90° corner. When fixed to
a round chimney pot they are likely to twist sideways, leaving
the mast and aerial at an angle where they can tip up the whole
pot. Tightening a lashing wire around a pot imposes a massive
strain. Chimney pots are heavy and when they break they have sharp
points and jagged edges — not the sort of thing you’d
want to hit you on the head.
So
what should the installers have done? Masonry hiding under rendering
is always suspect, because sometimes a chimney is rendered to
save the expense of repairing it properly. However, if a wall
will withstand the attentions of an energetic pneumatic hammer
action SDS drill without disintegrating it is a safe bet that
it will support a normal domestic TV aerial. Subject to that practical
test, the installers should have fitted pairs of wall brackets
to the side of the stack. With the two brackets a metre apart
the installations would have been perfectly secure.
My thanks to David of London for these two photographs.
|
Previous |
|
Next |
|
|