Edpm roof with plywood upstand against pebbledash

[davidc123]

I'm building a lean to shed and planning on installing an edpm roof. The roof leans onto a pebbledash wall and I've been a bit concerned that the contact adhesive won't be strong enough for the upstand on that surface, so rather than chase out all the pebbledash another option I was thinking of is to attach a thin ply upstand to the wall, glueing the rubber to that, then chasing the flashing in right above it.

Seems sensible to me but I haven't seen this mentioned or suggested anywhere so not sure if there's a reason for that. Does this method get used in practice at all?

 

[DAZB]

Trying to bond anything to pebbledash would be like trying to push a wet noodle so fixing a plywood bearer is a good way of doing it and either chase the preformed angle it into the wall at the top or stop it flush with the ply and set in leadwork to lap down the vertical.