"Dave Liquorice" wrote in message
ill.network...
On Mon, 27 Jan 2003 19:03:41 -0000, Rod wrote:

On the building side would I need to add plastiser to the mortar
and use a DPC?

Concrete floor is probably a bit OTT. I would just use a separation
membrane with some sort of gravel on top.

The DPC seems a bit OTT as well for a cold frame, unless as has
already been pointed out, the structure would bridge the DPC of
another. Not sure I like the idea of vertical DPC though, I think that
could trap moisture that ran down the wall. Best to leave a gap of at
least a bricks width IMHO.


I agree it would be better to leave a gap, but IMO, if the structure is to
be butted to an existing house wall, with the top of the frame brickwork
above house dpc level, and without incorporation of a horizontal dpc at same
height as the house dpc, a vertical dpc at the junction would help prevent
rising damp bridging the house dpc via the cold frame's brickwork. No dpc is
going to prevent rainwater getting on the external bricks above dpc level.
Treating the exposed bricks with a water sealant (encouraging water to run
off the surface rather than soak into the bricks) might help, if the design
of the 'lid' doesn't protect the adjacent brickwork.