"Claude" wrote in message
...
I want to build a pergola to support a grape vine over the deck. I need
to
span 6 metres and am thinking the only practical way to do this is to use
some form of parallel wires (eg tensioned stainless steel like they use on
yachts) set out at say 500mm centres. I'm wondering if anyone would have
an
idea if this would work or whether the weight of a fully grown vine would
eventually lead to sagging wires?



Using tensioned wire may work but a warning, if the structure begins to age
or is hit by a strong wind and starts to distort the tension in the wires
may become destructive where, if you had used timber members instead, they
would provide extra support and stiffness. If you mean span 6 m of wire
only, ie no intermediate support other than the wire, then I would be very
careful indeed.

See "The Australian Decks & Pergolas Manual" by Staines, it's about $30 and
well worth the price for practical, sound advice. He gives details of
overall design, the sizes and spacing of timber, strength of footings, the
lot.


David