Have I got a bee problem or a wasp one?

[Idaho]

Very possibly a masonry bee:

Masonry Bee
The masonry bee is a type of ground bee that will normally live in the ground, but if type of bee finds soft mortar between the bricks of a wall it is unable to distinguish between the mortar and its natural habitat. If you find bees going into holes in the brickwork of your home, fill the holes with a hard mortar mix to stop the bees digging it out to get back to the nest.

Although these bees have a sting it can not penetrate the skin
It is not considered a public health hazard

From: http://www.aberdeenshire.gov.uk/environmental/pests/bees.asp

 

[selamlar]

I believe mason bees are solitary tho, aren't they?

 

[Space Girl]

That's horrible and is what I suspect may happen. I can block up the hole with cement pretty easily but I'd feel bad killing a whole colony of bees

It'd be better than getting stung though sadly

blocking them in still kills the ones inside, and also they can scratch the cement out before it dries, we tried that too