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What length ladder and best place to buy them?
In message , writes
In uk.d-i-y, David Hearn wrote:
The guttering of our house is about 5.5m above the ground. I want a ladder
which will reach that height safely. I've no plans on doing any serious
work up there
[ ... ]
What is the recommended angle for ladders? If I need to reach 5.5m vertical
and the ladder is at the recommended angle - what length (extended) ladder
do I require? I've been looking at 7m+ ones - though I'm wondering whether
6.5m will be sufficient.
I'm pretty sure the suggested ratio is 1:4; that's what a moment's Google
with the words "ladder angle safe" produces, too. The less helpful sites
say "75 degrees";
Thus, for a vertical reach of 5.5m, at the 1:4 ratio, Mr Pythagoras says
you'll want a hypotenuse of at least sqrt( 5.5^2 + 1.4^2 ) = 5.7m
(minimally longer than the long side, since at these small angles,
sin(x) is only just a little less than x).
However, the ladder specs may be a little optimistic about the full
extension: to stop it bouncing alarmingly when you reach the middle in
your tapdance up the rungs, you may want a bit more overlap than the
2-3 rungs which full extension is quoted at. So a 6.5m ladder would have
just 0.8m of overlap if two-section; you might prefer the greater rigidity
of the 7m flavour, especially if your physique is closer to "cuddly" than
"boney" ;-)
I'd also want to allow for say 1/2 metre above the gutter as something
to hold onto etc. when working.
--
Chris French, Leeds
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