Please advise – roof flashing installation
vaczyz
| Posted in Construction Techniques on
We are in the process of getting a house built through a national builder. An independent inspector pointed out that our roof step flashing was installed over the WRB/house wrap, which according to the inspector is a huge issue (reverse shingling?) that will lead to leaks. Our builder and the roofing subcontractor claim that this installation is completely acceptable and simply one of many acceptable ways of flashing a roof and refuse to change the installation. Who is right? How serious is this and how likely is it to lead to problems down the road?
Replies
vac
The house wrap should act like a counterflashing and overlap the step flashing. Roof to sidewall flashing should also see a kickout flashing at the bottom of the wall.
If they think their way is proper, how did they flash your windows and doors?
It is axiomatic that a "national builder" will do it wrong, if it can be done wrong.
The wrap should be outside the step flashing.
If the siding is not yet on it's a simple thing to fix. If the siding is already in place then the damage done by "fixing" it might be worse than leaving it as is, however.
Dan's advice is spot on. It may also be worth noting that some builders install step flashing over WRB and then achieve a seal by using builders tape (such as Typar or even Zip tape) over the joint. IMO, this effectively forms a shingle lap condition behind the siding without cutting the house wrap and pulling it over the step flashing.
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Our inspector told us they didn't flash the windows correctly either. They cut out the windows completely in the WRB with no overlap and then did the flashing. Also does it look like they did the flashing under the front door over the porch correctly? Once again it is over the WRB which seems incorrect. I included some other pics including the windows, utility boxes, and step flashing. Thank you all so much for your help.
vac
Referring to this detail:
View Image
and your last picture of the roof to sidewall flashing-
There is no kickout flashing-you can expect failure behind the siding at that point. Maybe not now, nor in a few years, but only luck and caulk will defer real potential damage over time. I've repaired too many of these type of installs to think any different.
What type of siding is also important-vinyl allows water to enter easily (unless detailed properly) and does leave it a way out (provided it makes it's way down and over to the drain area).
At the windows-while I would wrap the sides and bottom into the rough opening b/4 installing the window-they did seem to take the housewrap over the top nailing flange after taping their way up the sides and then laying that over and tapeing as well. This flashing tape will self seal around siding / casing nails. Some will put the tape on over the flange/on the sheathing and then lay over and tape the house wrap. Either is acceptable.
Door- Cannot see how the sill was detailed but the flashing tape coming out from under the threshold and wrapped over on the sides suggests some sort of sill flashing. I still like to take the housewrap over that tape as any pucker in the tape will allow water to possibly work its way behind and the into the corner of the rough opening. Most door frame failure is at the corners-mostly the bottom of the jambs, but where caulk was the only defense-top corners as well. If there's a roof the porch-you'll probably be fine.
The silver coated flashing tape is to divorce the slab from the frame. Here again, I'd lay the housewrap over that flashing rather than behind. Some feel it is alright to do it the way in your picture-I don't happen to agree.
The unit you have a picture of-not a good enough view to see how it's detailed. There is alot of stuff in there-that could help..........
Again, what type of siding is going on this house?
A lot has to do with how much you trust the tape. If the proper sheating tape is used then lap doesn't matter so much.
As to the windows, it's pretty standard to install the nailing flanges over the house wrap and then tape at the sides and bottom. What you do at the top may be a different matter.
Thank you. What constitutes proper sheating tape? Can we trust the tape to hold in place for over 10 years? As far as windows, it looks like they installed the windows and flashing under the WRB then taped the WRB on top of the flashing. The top flap is taped down instead of being loose. The tape on the inside sill of the window does not cover the corners on some of the windows. Could you confirm if all of these are problematic?
The Tyvek-branded stuff is trustworthy, if properly applied to clean, oil-free surfaces. There are other brands.
But don't trust anything that looks like Red Green style "duct tape".
I can't really make out the pictures well enough to see where there might be problems, plus there's a degree of judgment call and legitimate disagreement between observers.
vac
It appears that the windows are done ok-consult the installation instructions for your windows-
The tape over on the sides is fine-
The slits up at an angle from each top corner looks like they taped the top flange to the sheathing and then let the flap of housewrap come back down and taped that back up.
If the top flange tape went over the side tape-that is correct. So is the taping at an angle at the slits.
Should it last for over 10 yrs? The use of this type of flexible flashing has not been around and in practice for much more than that. And I"ve not had the displeasure of taking apart any window/door jobs I've done since using the flexible flashing tapes.
It should last, according to manufacturers specs and proper installation.
Thanks. So as far as the roof, you're saying that as long as the roof & wall intersections are protected by some other membrane things should be ok? For some reason I thought that was what the step flashing was for? How would we know if the roofer used such a membrane?
As far as the windows, the discrepancy we noted with the installation instructions was that the top flap was taped down instead of being loose to allow water to escape and the peel & stick sill flashing on interior side of the window does not cover the sill corners <attached picture>. Are either of these significant?