Home>Discussions>EXTERIORS>attaching copper flashing to brick wall
7 posts / 0 new
Last post
copper flash
attaching copper flashing to brick wall

What is the best way to attach copper flashing to a brick wall? I just had my roof shingles replaced and the flashing above the porch roof to the 2nd floor (brick) wall was replaced with copper. The roofer says that he had to use steel screws to attach the flashing as fasteners made of copper are too soft to put into the brick. I am concerned that the screws and copper will react together and deteriorate over time.

Re: attaching copper flashing to brick wall

the horizontal mortar joint needs to be cut with a grinder so to slip the copper into it with a bead of caulking, a mechanical fastener will also help, the copper should be bent as a z flashing. if you dont know how to do it, best to get a mason to do this

copper flash
Re: attaching copper flashing to brick wall

Thanks for the reply. My roofing contractor did as you said but he used steel screws to secure the copper to the wall. Do you have any other suggestions regarding fasteners? Another contractor suggested using a copper washer to prevent the screw from directly contacting the copper or to insert a piece of wood into the screw hole and to use a copper screw. How far should the copper go back into joint created by the grinder?

Re: attaching copper flashing to brick wall

A possible solution: fiber washers.

Re: attaching copper flashing to brick wall

I'd get a new roofer. What you are looking for is properly installed flashing AND counter flashing. The counter flashing is an L shaped piece of metal where the very short L part gets tucked into the brick's horizontal mortar joints as said above. The flashing is an evenly sized L shaped piece of metal that gets put under each shingle.

If you go to copper dot org and search under "counter flashing" you'll come to a great FAQ sheet with diagrams. Let us know if that is what you really have. I think what you have is flashing, without counter flashing.

Re: attaching copper flashing to brick wall

The old-time roofers would brake the counterflashing with a 3/8" flat top and insert that into a raked-out mortar joint, and wedge the c/f in place with strips of scrap metal rolled into a cylinder and flattened, then driven in to the joint to wedge the flashing; the joint could then be mudded in, or sealed with Lexel/Geocel type polyurethane sealant. No exposed fasteners are acceptable, each one is compromising the integrity of the couterflashing. Let's assume for now that there is also the step flashing in place, until we learn otherwise.

Re: attaching copper flashing to brick wall

Go back in a year or two- the copper will be discolored and the steel screws (even stainless ones) corroded. It's called "Electrolysis" and occurs whenever two different metals are in contact with each other. Fiber washers won't help- the screw shaft will still touch the flashing, You could drill oversized holes then isolate the screws but that's a lot of work. At this point I'd just redo the flashing properly (tucked and wedged) or attempt a decent fastening with copper nails into pre-drilled slightly smaller holes, then counter-flash above it.

On a side note, most of the roofers I've seen here know little about flashing because they're paid to throw down shingles as fast as they can, not do flashing- and that means that they aren't going to spend any more time doing the thing that doesn't pay than they absolutely have to- they do it just well enough to get past their warranty period, period. 95% or the roof leaks I've dealt with were flashing related which kind of proves my point. Flashing is what separates the Tradesman roofer from the shinglers, so that's where you look to assess a Roofer's quality of workmanship- If the flashing is right, odds are that the rest is excellent too.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.