HazMatt-SKO
Senior Member
I neglected to consider the Gunk Funk Factor!
A larger gap might forestall the accretion of the littler crap, but would still be a PITA to clean behind.
Perhaps the small gap option, with flashing or a bead of caulk along the top, leading edge, and possibly trailing too, to keep most all but the airborne dust at bay.
At first, I thought a narrow gap would suffice, leaving enough space to perodically blast with a garden hose.I suppose it all depends on the amount of offset between the metal and wood and the protection the gap has from debris. Our bus seems to collect tree "gunk" in th strangest of places due to water running off the roof and down the sides.
A larger gap might forestall the accretion of the littler crap, but would still be a PITA to clean behind.
Perhaps the small gap option, with flashing or a bead of caulk along the top, leading edge, and possibly trailing too, to keep most all but the airborne dust at bay.