My fix was to use screen material formed inti a U-channel, taped in place and the fill the channel with expanding foam. The screen gives the foam something to grip and prevent it from running all over as you spray it. You can paint the tan foam if you like, but nobody is going to see it but you. Once it sets, you can trim any excess with a hacksaw blade or knife. I don't have a generator, so venting it was not a concern.