On Tue, 20 Feb 2007 12:43:24 GMT, John Stumbles
wrote:

On Tue, 20 Feb 2007 12:13:09 +0000, Stuart B wrote:


I have recently moved into a house, where there is a large gap around
the combi flue (i.e hole has been made, but never finished off). Can I
used expanding foam to fill this gap, or do I need to use mortar?

Maybe the OP meant on the internal wall.?

On the internal wall I always use one-coat plaster. Foam would look
terrible and risk over-expanding and spilling into the boiler.

Likewise I use mortar (sand & cement mix from the sheds) for outside.

But my reply was in response to

"You can, but I'd use mortar. If you do as you plan you really need to
cover
it with something such as a trim ring. PU Foam is not UV stabilised
and
will deteriorate in the sun. It is also soft and hardly a great
external
finishing material."