stepwise step instructions?

Can anyone explain how step flashing should be installed at a roof-wall junction? Are the individual pieces supposed to be sealed to each other? To the roof deck? To the shingles?

Also, what is the advantage of step flashing compared to a continuous piece of flashing?

 

Step flashing is applied like an extension of your shingle row. Finish shingle row, install step flashing over shingle and up on wall. Next shingle will lay over flashing. This is better than one piece since it gives a wash zone for every shingle, independent of the others.

 

How do roofers replace r flashing when installing new shingles at a wall-roof junction when the siding is up already? This is not lap siding - it's T1-11 sheets

 

When I went to Louisiana to do some volunteer work after Katrina, I noticed that no one there used step flashing, it was all continuous flashing. Tearing off the roofs, you could see that the continuous flashing leaked... a lot. It seemed really stupid to use an inferior method of flashing in an area that gets so much more rain than we do up here in Nebraska! No one does that here!

As Larry said, when each shingle is individually flashed, it is far superior. Rainwater runs on top of the stepflashing for 5 or 6" and then it's shed onto the next one, with no potential for a leak onto the felt. When you use a continuous flashing, that water can get under the shingles near the top... spread out on it's way down, the volume of water under the shingles increases the longer the run of flashing is (10ft... 20ft...30ft..)... and by the time you get to the bottom of the flashing, a huge amount of water is under the shingles, has run off the flashing and is now spreading out under the shingles and onto the tarpaper/roof deck.

When applying step shingles, there is no sealing or caulking done anywhere, no tar is needed after you are done, and the step shingle only gets one nail in it... and that is the one that goes through the shingle and holds it to the roof. The upper leg slips behind the siding and does not need to be nailed.

If you have a specific question about an outside corner or something unusual, post a picture and we will be glad to look at it.

 

"Slips behind the siding" sounds simple enough but see my other question a few minutes ago. Sheet siding in FL is nailed 4" OC on edges. This means nails 0.25" from bottom edge, no slippage space.

 

Don't see the other question anywhere....

4" on center? That's nuts! They must have installed solid blocking above the roof deck... ordinarily there is nothing but the studs (16" OC) to nail to. And if the siding is not at least 2" above the roof deck, I would lay a 1x4 on the roof, then take a skilsaw, set it as deep as your siding is thick, and run it down the roof deck and cut the siding off so that it's roughly 2" above the shingles. That cut line might be just above most of those nails. Then you should have enough room to get a prybar behind the siding and gently pry those nails out.

 

BTW I've tried several forums and that's the first clear answer i've gotten. Thanks! Next question is how to install when sheet siding is already up. Other question got deleted accidentally but should be back shortly.

 

It's code although apparently wasn't when the house was built in early 90s. I should clarify though, this isn't a real situation yet. I'm replacing the siding and trying to follow code for nailing it (yes it involves new blocking) and I'm wondering how a roofer would replace the roof-wall flashing if I have the shingles replaced in the future. In some cases the original siding was nailed to blocking that wasn't nailed to anything, so when I removed the siding it just came off with the "blocking" attached.

Am I misinterpreting code in installing the new siding? With 16" between studs, there would be a lot of flex at the bottom of the siding without blocking.

 

Generally speaking, step flashing is not replaced, it stays in place when the roof is replaced and it is reused. That's pretty much true of most types of flashing. They are reused wherever possible.

I'm not familiar with Florida codes, but if your siding is structural and requires additional nailing because of hurricanes, that makes perfect sense.

 

Yes, it's structural. 5/8" T1-11 can be used without addtional sheathing. Like sheathing, the detailed nailing provides rigidity, continuous load path ground to roof, and impact protection. I forgot to mention that code now does require blocking at edges if they don't overlay a stud or horizontal member.

So it would be important to tell the roofer not to shred the existing flashing as he removes the old shingles! Because one of the current problems is where an addition was added the original flashing was installed OVER the existing siding (heavily roof-cemented), but the siding of course turned to mush anywhere near this juncture. I think I've heard this called "counter-flashing".

That other question is still not posted back. It was about how roofers replace flashing in this situation.