Worked on a job this weekend where I had to lower the existing aluminum gutter to below the weep holes underneath a patio slab. This residue looks like stalactites at Carlsbad Caverns.
The picture shows two courses of brick below the patio stone, with an electrical conduit traversing the second course of bricks. Then I think I can make out an EPDM or similar membrane on top of the copper flashing. At the membrane/copper interface are clear plastic drainage tubes, which by the way, are completely filled with calcium carbonate(?) What looks like dripping foam are actually hard, multi-layered stalactites.
My job was to lower the gutters so that the copper flashing fit over the back of the gutters. I am fully aware of the problem of any galvanic reaction which will occur between the two dissimilar metals. It seems the homeowner wants to do this only as a stop-gap measure for the time being, meaning, it’s less expensive to just lower the existing gutters at this time, than to solve the problem of the source of efflorescence and install copper gutters.
I welcome any or all comments and/or criticism.
Regards,
PK
Replies
Maybe you could use Vycor or Water and Ice Shield between the aluminum and the copper to act as a dielectric insulator between the two. Could also be that one of the metals (I'm guessing the copper) is making acid with rain water and that is dissolving the lime in the mortar and re-depositing it elsewhwere. Could be combinations of things, but I guess I'd try insulating the two metals from one another to start with.
CU ions will still be washing thru the AL gutter dissolving th ebottom of it.I think it looks perfectly unique like it is!
;)
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I could see a faint image of the Virgin Mary on it.
efflorescence is the salt be flushed out of masonry mortar type product. keep it dry no problem. its reaction to flowing water
I've seen worse in subways and parking garages. I'm guessing that you rarely ever get a "cleansing" flow of water over the surfaces, just the slow drips, so the deposits build up. Actually, with the gutter moved below the buildup would probably stop.