"martin" wrote in message
news
On Sun, 30 Nov 2003 09:24:01 +0000 (UTC), "Franz Heymann"
wrote:


"Philip" wrote in message
. ..

"Jane Lumley" wrote in message
...
Thanks so much to all for your help - we've found a house with an
acre
of land.... but I'm not saying any more in case one of you gazumps
me!
.

Thing is, said acre is currently rather exposed to wind and traffic
noise, so dh and I are eager to make a walled garden by building
brick
walls around at least part of it. Are we mad? I've looked at
several
websites and the art of bricklaying seems very jargon laden. Does
anyone know of a site in plain English? And has anyone ever done one
of
those night-school bricklaying courses?
--
Jane Lumley

I am not quite replying to your exact question but hopefully, I will
add
something of use here.

You mentioned that the site was exposed to wind, and you were proposing
to
build a wall. Well its just that walls are not that good a acting as
wind
breaks. The problem is that the wind hits your wall and is diverted up
and
over. The results is lots of eddys and a more buffetting effect on the
leeward side of the wall.

A tall hedge on the other hand filters the wind. The wind hits your
hedge
and is slowed down by the branches twigs and leaves. In these
circumstancs
the leeward side of the hedge would be a more peaceful place than the
leeward side of a wall.

And that is not just a legend. I had a book (where is the damn thing?)
with
test results from research on hedges and walls as windbreaks. A hedge
provides wind shelter for more than twice as far downwind than a wall of
the
same height.

It's a bit like the difference between a solid break water/sea walls
and barriers of large loose rocks, now so popular in North East
England's sea defences.
The first diverts waves and the second absorbs waves.

Yes. Identical principles.
The principle of least efficient fluid flow - to - mechanical energy
conversion.

Franz