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?

Claude wrote:
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?


Depending on thickness of cable, and the tensioning technique it should
hold the weight OK.
Look at other pergolas in your area. You may find, if youre building the
frame out of wood, that you would have to make sure the tension is
retained at both ends...without anything collapsing. So reinforcement to
carry the weight would also be an issue.
A metal frame sounds like it would work...
Sagging wires would be the least of my problem. They would get covered
by the vine anyway...

Jonno wrote:
Claude wrote:
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?
Depending on thickness of cable, and the tensioning technique it
should hold the weight OK.
Look at other pergolas in your area. You may find, if youre building
the frame out of wood, that you would have to make sure the tension is
retained at both ends...without anything collapsing. So reinforcement
to carry the weight would also be an issue.
A metal frame sounds like it would work...
Sagging wires would be the least of my problem. They would get covered
by the vine anyway...

Use heavey fencing wire attached to turn buckles then they can be adjusted
if they do sag - their pretty cheap at bunnings
Lushy

"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

G'day Claude,

What is your priority here, covering the pergola you wish to
build or growing a grape vine? I'm not having a shot here, it's just I'm
more interested in the choice of grape, rather than how it's held upright.
If you are going to use this vine to produce fruit or leaf, you are going to
be cutting back the bulk of each years growth every winter, thus reducing
the stress on any supports. With the years, the 'trunk' of the vine will
become self supporting, grapes live for eons and I'm told that some wine
makers prefer old vines for quality if not quantity.
If you want privacy from this vine then please consider that
it will be bare for five or so months of the year, and the rest of the
year, the birds will be 'you know whating' all over your deck while they
argue about which flock will eat your grapes and leave droppings all over
your car.

Build the pergola you want, then choose your plants, if you
really want grapes, then I advise you not to plant it near your back door.
There are a number of ornamental grapes, chosen for their leaf colour and
they don't fruit, but they are still deciduous.

China
Wingham
NSW