Colette A. O'Brien writes
Hi all

I am moving my greenhouse from the darkiest, shadiest part of the
garden to a sunnier area. I decided on a concrete base as I never grow
anything in the soil of the greenhouse, and I thought it would be more
rat-proof!

What sort of rat problem have you in mind? Rats coming into the
greenhouse, or rats living underneath the base?

We live in a very windy area and so the greenhouse needs to be firmly
secured.

I have a builder friend coming tomorrow to lay a concrete base for me,
but now I am rather belatedly having second thoughts. I am wondering if
a concrete base is a bad idea because of drainage - how to I ensure
that water can drain freely away?

You can tell I'm a bit clueless about all of this, any advice would be
very welcome.

On our first greenhouses, we had a concrete base with a 6inch brick
wall, and the greenhouse firmly bolted on to the brick wall. Therefore
no water could get in.

Our current greenhouse is directly on to the concrete base, and in heavy
rain we have problems with seepage under the edge. We have laid a patch
of slabs in the centre, thus raising the floor in the central area about
an inch, so that any water stays under the staging and eventually drains
back out the way it came in.

I think if it were a smaller greenhouse dampness in the winter would be
a problem, but as it's a reasonable size and with good air circulation,
we don't have any problems either with mould or with cacti rotting.
--
Kay