I have lots of wasp activity at my garden "bee-hotel" at the moment. I managed a sequence of photographs of an apparent Pemphredon wasp provisioning with aphids, sealing the nest-hole with resin and then reinforcing it with wood fragments gathered for adjacent holes. Here's a link to the photograph and description on my Flickr account:
Has anyone else observed this? I can't find accounts of this happening with Pemphredon spp. Other holes have Passaloecus wasps returning with aphids. Their holes are sealing with resin, but with no additional reinforcement.