"aquachimp" wrote in message
...
On Apr 16, 8:29 pm, "rtreter" wrote:
Hello -

I'm planning to have a retaining wall built to hold back a 1 metre height
difference between two gardens, It will be built from blocks mortared
togther. I guess the concrete footings will extend about 1 metre below the
surface of the "low" garden. There are some trees within 30 cm of the
planned location of the wall, their trunk diameters range between about
5cm
and 20cm. I don't want to kill or substantially harm the trees.

The builder I'm getting a quote from says he will put lintels into the
wall
and footings so that roots larger than about 1cm in diameter don't have to
be cut. Is this a sensible approach, for the trees and/or the wall?

Thanks

If you have roots which vary in diametre from 5cm to 20cm, and the
builder 'accomodates' say, a 8cm root, will the 'accommodation'
suffice when it gets to, oooh, say, 27cm?

So, I'll presume what the builder is hoping to be able to do is to
create pillars of concrete on to which to rest the lintels; After all,
I would think that there would be no point in putting concrete under a
root. So, essentially, the wall would be built on a bridge of lintels?
Sure would benefit drainage and therefore lessen the pressure on the
wall to some extent.

And I'll assume that the idea will be to have, say 4 lintels abreast
and in staggered formation: (like as in laying grass turfs) in order
to limit the potential of the cracks which would most likely occur if
they weren't laid thus.

A lot of trouble, and expense for a 1m high retaining wall. Why not go
for a drystone wall?
And whilst I think of it, I've seen this done (albeit only around 70cm
high) with stkaes driven into the ground, leaning towards the bank of
earth and wooden slates nailed inbetween.

Thanks for the comments.
I think the wall needs to be a fairly substantial one, because there are
buildings about 4 metres away on the high side.
The height difference is currently retained by a wooden fence with 4" posts,
but it is starting to lean over.

Does anyone have any comments on replacing the existing wooden fence with a
fence using 5" concrete posts set in concrete, with concrete gravel boards
to retain the soil. I think this is known as a "Berlin Wall" in the building
trade. Hopefully it would be possible to position the posts so that they
don't interfere with too many roots (there are only 4 trees along the 9
metre fence).

I think I'm going to get an engineer in to advise, but the idea of using
concrete fence posts and gravel boards appeals to me initially.