Victoria Clare wrote:
My driveway & garage is raised: at the front there's a retaining stone
wall, facing a sunken road and at the side there's a cornish bank
(unmortared stone & soil) facing a private lane (about 10-12 feet lower
than the drive).

Around the driveway there's bit of space filled with odds and sods -
shrubs, the gas-tank on a concrete plinth, and a small (oddly-placed &
leaking) pond.

Now, I have a plan to move things about a bit - pave part of the lawn to
allow a bit more parking space, move the gas-tank a bit, convert that space
to parking, etc.

However, I am very aware that I have no idea how much weight the cornish
bank can take, how much space I should leave around the parking bit to be
sure it's not at risk, whether taking some height off the top would make
things more stable (and thus allow an increase in the parking space) and so
on.

I'm not even sure who to ask about this. A builder ? A surveyor? a
landscaper? Someone else?

I'd like to take professional advice. The private lane is the only access
to the outside world for several houses, so I want to be quite sure I'm not
going to risk trapping all of the residents.

Victoria

I sympathise. At the end of my garden is a 6ft drystone retaining wall
that is at leat 100 years old. It's very bulgy and full of roots from
nearby trees.

Your problem is that nobody with any sense will tell you it's OK to park
a car near the top of a structure like this. A structural engineer will
be able to design a wall that will be strong enough BUT it will probably
have to have a base as wide as one third of it's height.

Building such a wall is obviously a non trivial job. If the existing
wall is in good condition I'd be inclined to go ahead with your plans
anyway BUT keep a very careful eye on the wall. If there are any signs
of movement you'll have to take evasive action which could be
expensive/time consuming.

HTH

Nick Brooks