Paint the surfaces with an oil based paint or
polyurethane coating.

I've noticed they seem to like the underside of the horizontal strips
of wood where I've missed staining. However, there are a few places on
the vertical posts where they've gone through the stain. I've had
minor problems with these pests in previous years (but didn't know
what they were), but never this bad. There all over! Any ideas why so
bad this year?
The Wobulator

Poly the areas again. They left my shed alone once I painted the bare wood. I
then left the dog house untreated (as they don't sting without severe
provocation) so they would have an alternate. As to why it's so "bad", count
your blessings, many areas are in a "bee emergency" without the pollinators
available.

Just my 2 cents.........
Christine