My house has a very large and boarded attic and I want to make access
easier by replacing a flimsy metal loft ladder that someone fitted in
place of an original wooden ladder. The existing trapdoor is quite large
(690x1450) so I'm tempted to make my own replacement ladder to avoid
having to put filler pieces in the ceiling - either a 3-section z-fold
or a 2-section slider. Making the ladder would be straightforward but
it's going to be heavy (especially when connected to the trapdoor, which
is timber framed and solid) and I can't see how to counterbalance it
safely. I could set-up 2 wires to pulleys on a purlin and use weights,
but the load will change as the ladder hinges down. Springs would change
their rate and probably do the job, but I can't see how to design the
mechanism and trial'n'error would be a pain.
I may give-in and buy an off-the-peg loft ladder, but it would be useful
to hear whether anyone else has tackled the same problem.