I've got wasps in my outdoor shower. They come and go all day from behind a trim board between a gutter and the shingles, and I sprayed at night 3 times, each time emptying about half a can of bug spray. I've seen a few dead wasps and a couple of chunks of discarded nest, but still there is much activity coming and going all day.

 

And?

You got to get to the nest, might have to take something apart to get to them!

 

Hot shot has a modest residual effect but that may be all you need. I'd keep it up a few more times. See if you can figure out exactly where the nest is and soak it. There are products with longer residual benefit but that's most likely unnecessary. Be patient.

 

Like Tony said, it could still work through attrition. Otherwise, the nest is deeper inside so direct nest treatment can be accomplished. Any chance that this is an unfinished garage and you can attack it from inside on a step ladder to get to the soffit?

Meanwhile, look for aerosol insecticides that may have a tube or hose on them so that more direct injection can be performed. Doesn't have to be a wasp/bee spray per se, but should be a residual. Crawling insect spray would be good.

Here's an example. The aeros with a smaller/stiffer straw/tube would work too, but sometimes they come off of the aerosol when bent.

https://www.homedepot.com/p/BioAdvan...-12140#overlay

 

hey, I talked to a guy that said a powder insecticide is the way to go. he said you need a license to buy the best stuff but I see Sevin Dust and Rentokil online. Thoughts??

 

Sevin dust would be fine; don't know what Rentokill dust is. Lowe's and Home Depot and Tractor Supply carry Sevin, at least here in PA. Wasps, bees, etc. are easy to kill with either liquid, aero, dust insecticide; the hard part is getting the insecticide to the nest. How are you going to apply the dust? Does it come in or with an applicator? The closer to the nest, the better.