I live in the Uk .Every year I have to deal with wasp nests
At the first sign I spray the nest morning and evening with a foam wasp nest killer and this method has been successful every year
This year I saw wasps flying under the roof tiles to our single single storey extension The only access to the nest would be to remove the tiles and trace the origin
Spraying foam into the area where the wasps entered the roof had some success but did not solve the problem
On Amazon I saw a insect duster puffer and this gave me the inspiration for an alternative solution
I took a piece if narrow metal tube and reduced the diameter by clamping it in a engineering vice so that the tube could be inserted under the tiles
I attached the metal tube to a 1/2 inch diameter piece of old washing machine pipe with duct tape
Next using a funnel I poured the wasp powder into the washing machine pipe
To blow the powder under the tiles I used an electric air pump for inflatables attached to the washing machine pipe
The power of the pump was sufficient that you could see the powder vapor stream out of the surrounding roof tiles
Result no more wasps
https://www.amazon.com/s?k=pool+infl...f=nb_sb_noss_2
Suggestion only use a small amount of powder and repeat the spraying several times
On my first attempt at spraying the end of the metal tube under the tiles must have been in contact with a solid surface and the powder simply blew out where I put the tube in so you will need to experiment