On Tue, 22 Jul 2008 17:21:33 +0100, Mary Fisher wrote:

I have read that by the end of the year a wasps nest in the ground or
in a loft etc may be the size of an armchair,

That would be VERY unusual if you're in UK.

and would expect that if this is taking place inside a partition wall,
it would achieve about the same overall bulk but be spread out some
metres between the two walls. As far as I can see there is no way
they can get inside the building from the partition. I have read that
wasps
are quite beneficial to the environment and especially the gardener so
my
inclination is to leave it be, and try to remember not to run towards
the
airbrick shouting and waving my arms and banging things, etc. I think
a
wasps
nest is deserted after one season- I wouldn't be quite so keen if I
thought
this was going to repeat year after year.



All the above is correct - except that the sprad of the nest will not be
more than a metre, I think, depending on the depth of the cavity. Most
wasp nests are perhaps the volume of a large football but not a large
beachball. Their shape is determined by the space they occupy.

I'd go along with the spread a metre or so diameter from the entrance
hole. I had one in the eaves of a loft, that was about 3' long 18" high at
the front and about 9" high at the rear, discovered it at the end of the
season. A little larger than a beach ball...

Thanks for being concerned and intelligent about it!

Agreed if thier flight path or entrance isn't going to bring you and them
into regular close contact leave 'em be. They are good at keeping garden
pests down.

I only have two very slight concerns. One is damp bridging from the outer
to inner skin of the cavity wall via the nest and the other possibilty of
blocked ventilation into the cavity. Wasps using airbricks as access isn't
all that common I wonder if this brick is damaged in some way either
aplastic one with naggered flyscreen or broken brick one making the
ventilation holes just that little bit larger.

When they have died off in the autumn gone it might be worth taking that
brick out and replacing it, at the same time you could clear the cavity of
the nest.

--
Cheers
Dave.