telescopes on concrete roof

In article , Maurice Gavin
writes
We need some practical advise re mounting telescopes on a large flat
roof [immediately overlooking fields to the E/S/W] to minimises
potential vibration mainly from dozens of observers walking about.

We are aware of the potential thermal problems from the building
- a substantial 1930s three storey brick structure with protective
parapet and rc asphalted roof. There are no pumps/ machinery/ people
within the building and no option for independent piers down to ground
level. The asphalte membrane cannot be disturbed to mount the
telescopes direct onto the concrete structure below.

The scopes range from 10cm - 40cm aperture and weight is not a problem
for roof loading. Non-portable telescopes will be protected with
run-off sheds/ grp domes.

Any thoughts? Should the walk-about area be padded and with what?
Such mats must remain in place and be safe, self-draining and
rotproof. TIA.

Try alternate layers of 3 to 4mm gasket rubber and lead, 4 layers of
each, top off with a small paving slab , used a similar system on a mono
layer forming trough to good effect .... Jon V
--
Jonathan Vogel