Spray foam insulation prep question

[bridg73988]

I am going to use spray foam insulation. My question is, the people that have spray foam insulation, did you have to strip the black sticky stuff off the roof and walls that held the original insulation on or did you just spray over it? I'm concerned that the foam won't stick or stay stuck if I don't strip it but that stuff is dang near impossible to get off. I welcome any input and experiences before I move on with this next step in my build.

[TJones]

I stripped off mine and it was miserable but I'm glad I did. I think you could test a spot by spraying some Great Stuff on it and see how well it sticks. I only thought of this after I had mine scraped off.

Ted

[bridg73988]

Good idea! Thanks for the input. I can try that this weekend.