Aluminum siding and adjacent roof

I have seen it done a few ways, but with aluminum siding, what is the best way to cut, seal, flash or ??? where it meets a lower adjacent roof?

sorry the picture is not better view… :roll:

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I’m don’t see why it would be any different than with wood or vinyl.

well it is a little different… wood = 1" reveal and metal flashing; vinyl = typically less than 1" plus a vinyl trim piece installed… never scene a similar trim piece installed on aluminum… for instance here the siding is just cut, tight to roofing… I would like to have seen some flashing… but was curious as to a technically correct installation…

There should still be flashing behind the siding regardless of material it is made from and underneath the adjacent shingles. I have seen what you show in your picture too and it always looks unfinished because basically it is. There are J channels available for the cut edges to fit into just like with vinyl. It does costs extra to something right so the installers will sometimes cuts corners and costs by doing it “half-fast”.

exactly… and when cut this low, it is almost impossible to tell what is there for flashing… certainly no proper step flashing present… Gerry B just shared the idea of J channel for the aluminum siding as well…

thanks for input guys…

Looks like it probably has J channel / Roll back flashing. There seems to be a hump at the wall to indicate this. If no hump is present at the walls, it should be either strait flashing or step flashing. Usually you can lift up one of the tabs at the wall and if you see flashing, it’s step flashed which is the only way to go. Strait flashing allows the water to side track across the top of the shingles unless you goo the edge of the metal before installing the shingles. Rollback/J channel flashing even when install properly can clog up with debris so it’s no good either. Most of the time I see the roofers have beat the roll back edge down where they secure it with nails and seems like some of them don’t understand what the raised edge is for and beat it down to eliminate the hump. If they do install a siding J channel it’s nice if they lave it up maybe an inch so new flashing can be installed when it is re roofed. When the roof is torn off sometimes the tear off tool can slip under the siding and jab a hole in the flashing. So even if it has good step flashing, most of the time it’s best to re-flash it again.

If that wall adjacent to the shingles is inside an attic, sometimes you can see the flashing from inside, not always. I do not see any J channeling on the siding. The rough cut edges can be seen right down on the shingles as you said. You may have to look for an area where the cut isn’t so tight against the shingles and see if you can lift the bottom edge to see behind it. Interestingly, I’ve been through a couple of EIFS classes, some for certification and others put on by one of the manufacturers of EIFS systems. The incidence of moisture intrusion in home other than EIFS is almost the same regardless of the type of siding. Almost always due to things just like this. Poor flashing or no flashing in areas critical to proper flashing and sealing. I see this same kind of work myself. You just have to press in and spend the extra time. The one thing I hate more than anything is additional trips into a hot attic or nasty crawl space but you just have to suck it up sometimes and do it. Good catch though! A lot of inspectors would have totally missed that.

it really depends on when the siding was added and when they installed the roof.if the roof is older than the siding then they could have properly step flashed the roof against the side of the house.before adding the siding,and then just terminated the siding at the shingle deck. the only thing i see that could be improved is there should be a channel installed at the shingles.installing this at the shingles gives the angle cuts on the siding a better finish and helps keep bugs out.i am a metal roofing contractor located in the central pa area.i have been involved in the metal roofing industry for about 11 years.since then i have fabricated many different applications of metal roofs. these have been anything from affordable mobile home re-roofing projects to beautiful barn roof resterations and also to high profile standing seam roof fabrication projects like 7 springs skier services center in somerset,pa. the metal i use comes in 12 beautiful colors and is covered by a 25 year paint performance warranty. underneath this paint is a substrate with a 20 year corroision warranty. or phone: (814)224~4268.thanks,keith.