In article ,
janet.bennett wrote:
Yes, I saw the new gardening programme last night, but unfortunately they
don't quote the number of bags and sand and cement you need. Thanks for
advice.

I've posted the same question to the DIY newsgroup, and someone has
suggested 'ready mixed post stuff', but its about £5.00 a bag. Wanted to
know if anyone knew the amount of sand and cement I'd need, so that I can
compare prices. Once again thanks for advice.

See Cormaic's pages. One part of cement to 3-5 of aggregate is fine,
and you can use sharp sand instead of aggregate if you have to.

But my advice is NOT to use concrete at all! If you build a pergola
properly, it will support itself and you will not have trouble with
the concrete when planting or removing it.

A reasonable height is 2.25-2.5 metres - much lower and things growing
over it will strangle people as they walk through. What? You aren't
growing a Climbing Triffid? Don't bet on it ....

For that, you need the posts to go down about 75 cm, though more does
no harm. Concreting in only reduces that to about 60 cm, so you have
gained little. Leverage is proportional to the square of the distance.

I would recommend 3.3 metre posts, though you can easily bind two
2 metre ones together with galvanised wire. Don't rely on screws alone.


Regards,
Nick Maclaren.