Building a retaining wall close to trees

 

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

 


Just to clarify, the trees are in the lower garden.

 

wrote:


Sorry, I can make no sense of this at all.

I doubt that 1 metre of footings will be put in below the surface of
the bottom level.

And are you seriously saying that the wall footings will be within 12
inches of an unspecified number of trees and that the builder is going
to accommodate all of the tree roots larger than 1/3 of an inch, not
cut them and allow room for their future growth?

I am boggled.   Are you using a builder or a conjuror?

He is suggesting building a wall within 12 inches of trees, some of
which have trunk diameters of 8 inches, without cutting or disturbing
their roots.

Why bother with such an impractical project.   I would stick in a
graded slope and live with it.






--
(¯`·. ®óñ©  ©  ²°¹° .·´¯)

 

wibbled:


If a wall is required, I would consider a curved wall - that's one that
leans over and into the earth mound - see a few ancient ones round here,
all of one brick thick and they've survived. However, won't work with
modern building methods (ie hard cement). If doing such a wall, I'd lay
the first course onto earth about 1 brick under the surface direct to
dirt and use clay or lime mortar for joining them. They work by the
physics of a graded slope but you can get away with a someone sharper
slope as the bricks reduce the tendency of the earth to wash down with
rain and the weight of the bricks works to balance the pressure of the
earth. Think dry stone wall on a sideways lean.

These sort of walls typically hold back 2-2.5 ft of earth bank quite
happily for decades - dunno if that is sufficient for the OP.

Then accept that as the trees grow, the wall moves and bits of it may
need adjusting and re-bedding.

The modern version of the same line of thought are these:

http://www.dme.co.za/sites/site1/images/Brick_Simulation/RWBD.jpg

Got them at the local kiddy nursery - simple, effective and laid "dry".
Made of concrete and can be planted with ground cover plants like heather
and creepy things to make them look good. In the local case, I think
(without a tape measure to hand) they are holding back a bank about 3-4'
high at an angle of about 15 degrees off vertical. Work by interlocking
and dead weight (once filled with earth). Again, the trees may move them
and it won't matter too much. When/if it matters, disassemble and re bed
the damaged section to accommodate the tree. Building next to trees
requires the "earthquake" mentality - either stupidly strong (hoover dam
strong) otherwise the tree will prevail eventually - or make it flexible
and accept Nature.

Cheers

Tim
--
Tim Watts

Managers, politicians and environmentalists: Nature's carbon buffer.

 

On 16/04/2010 23:27, Tim Watts wrote:

Excellent advice Tim, I was going to suggest a dry stone wall until I
saw your contribution.
Cheers
Don