We own an 1860 Victorian. The roof has two symmetric, intersecting gables at right angles. There is a cupola at the intersection. The flashing around the cupola has been leaking for 140 years, judging by the discoloration of the beams in the attic. (When we moved in the attic floor was covered with plastic sheeting). It only leaks when there is a lot of rain associated with high wind. We reroofed in 1977 and replaced the flashing. It still leaked. We replaced the flashing about 5 years later with step flashing. It still leaked. Fortunately, conditions that make it leak are rare enough that the wood has time to dry in between, and there is no rot yet. We are about to replace the roof, and would like to fix this problem.
My theory is this: that the wind creates a high pressure area where the cupola meets the roof (like the hood/windshield intersection on a car), and that this high pressure makes the water flow toward the edge of the flashing under the shingles. When the wind is strong enough, and the water generous enough, it gets to the edge of the flashing before it gets to the edge of the roof.
Maybe 20 years ago I read in Fine Homebuilding about a flashing technique to counter this: the edge of the flashing was softly folded back and held down with a roofing nail not driven home, to make a lip at the edge so the water can’t flow off the edge.
Does anybody agree with my diagnosis? Any other diagnoses? Any experience with the flashing method I mention? Any other suggested methods? Note that each person who has flashed this roof recently has been absolutely convinced that his flashing would cure the problem. I can’t vouch for the first guy, who is now beyond my reach, but he is probably included.
Replies
Is this a functioning cupola -- one that vents roofspace air to the outside? If so, then the source of the water leak probably has nothing to do with flashing, or exposed nailheads. It's probably just wind-driven water getting into the inside of the slats, then dripping from there. Check the design of the vent slats -- maybe something can be added to trap that kind of water intrusion, and send it back to the outside.
Or if it is simply decorative, has anyone looked under the cupola? Does the roofing/flashing completely cover the area that is covered by the cupola? If not, then rain is getting into the cupola, then seeping through the unprotected area of the roof.
Unless you're the lead dog, the view just never changes.
This is a habitable cupola, reached by a stair, with three double hung windows per side. I don't think anything is getting into the cupola.
"I don't think anything is getting into the cupola."Fair enough, but it wouldn't be the first "roof leak" that is actually a problem in the siding on the wall above the roof.Last time a customer called me to say the roof I installed leaked, I "fixed" the leak by putting plastic over the window above the roof. He then got his own storm window.Rich BeckmanAnother day, another tool.
I tend to agree with the above post that the cupola itself is allowing wind=-driven rain to enter and stain.
but if not that, it is also more likely that wind sends rain through the siding in the cupola and behind the up-edge of the step flashing if there is no tarpaper behind the siding and over the flashing.
The flashing style you refer to uis called a return hem
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
lum... i suggest you post a couple of pics of your cupola
you'd get a lot more valid responses
If cupola is non-functioning (decorative), I would put bituthene on the roof under the shingles where the cupola will be. Attach the cupola with as few nails as you can get away with (or even better would be a bracket on the roof at the intersection, then use threaded rod from peak of cupola to bracket) and maybe having scuppers in the bottom of the cupola to let any water that enters to get back out.
wonder what happened to lum ?Mike Smith Rhode Island : Design / Build / Repair / Restore
Well, it is Valentine's Day--maybe he's off in a love nest with his honey. ;-)
lum ?.... nah , he wouldn't do that to us
speaking of Valentine's Day...
did i tell you my wife left me for younger man ?
View Image
Mike Smith Rhode Island : Design / Build / Repair / Restore
Edited 2/14/2005 7:55 pm ET by Mike Smith
so whens the party?
Now that's robbing the cradle! Cute baby. Congratulations!
Sorry guys - I have been (and still am) sick (just a very bad cold). I am going to take a picture of the cupola right now.
Here is a picture of the cupola (if I can figure out how to attach it).
Here is the pic for dialups!Edit: That is one fine cupola!!!Rich BeckmanAnother day, another tool.
Edited 2/15/2005 10:33 am ET by Rich Beckman
that's some wrkmanship and worth holding out for..
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
lum.... have you looked at the windows real close..
especially the sills ?
View ImageMike Smith Rhode Island : Design / Build / Repair / Restore
That is a beauty. inside the cupola, are there baseboards? If so, could you carefully pull one and do a tiny bit of exploratory plaster demo to get a look inside the wall cavity, just above the sole plate? Use a bright light and mirror to check the inside of the cupola siding and the bottom of the window. If the baseboard's big enough, it'll cover the patch. That'll tell you for sure if the source of the problem is the flashing, or someplace higher.
-- J.S.
To All,
I would check the window sills first
and also be very curious about that area that looks like a white painted trim board right about where step flashing would be running under the siding.
also---for yucks I would look where the valley meets the siding---and also that stove pipe and the mounting bracket
In fact everything looks suspicious---lol
Stephen
Edited 2/15/2005 3:23 pm ET by Stephen_Haz
Actually, as I recall from the last time the flashing was done, the flashing does not go underneath the siding, but only underneath those boards.Thanks, everybody. I will investigate under the baseboards and the windowsills. As you can imagine, there has been a lot of rot on the windowframes (repaired with epoxy), and the sills are probably in very bad condition (I don't get up there very often). Hard to get a painting contractor to agree to paint it. What are we looking for? No drains to the outside? I could take a picture of the framing inside, if anyone would be interested.
If the flashing doesn't go under the siding---but just under those trim boards------
I think ya just found your leak.
Congrats!
Stephen
When they replaced the flashing, they removed the trim boards, but did not remove the siding. That is all I remember (but memory does not serve so well anymore...). I am attaching several pictures from the inside.
Unfortunately, I can't see the pictures while I am replying, so I will have to give somewhat vague descriptions.First is a general view of the framing toward the SE corner. The wood is hemlock, I believe, and it darkens when wet, and bleeds strong tea. The siding on the S side of the cupola looks to me as though it has been wet. When it has been wet longer, it effloresces whitish.The other shots are of the flashing region where the cupola siding meets the roof line. I have shots of the SW and SE lines and the NE. These have all been leaking. There is also a shot of the top of the valley flashing on the SE corner, which has been leaking (note chalk marks), as well as a spot at the bottom of the valley flashing on the NW corner. Somewhere in there I think you can see the sills of the cupola. They don't look as though they have been wet.The window sills all appear to be in good condition (amazing). They are all pitched strongly to the outside in a continuous slope from the inside of the sash - that is, there are no water traps.
lum ... your pics are too big..
download Irfanview ( freeware) and resize them to under 100 K
click on them to view them yourself.. you'll see what i meanMike Smith Rhode Island : Design / Build / Repair / Restore
If I'm interpreting this correctly, 398 is the most relevant picture. It's looking up at the underside of the cupola floor, which is much higher than I thought it might be. It shows a lot of water having been well above the flashing where the cupola meets the main roof. Therefore, windows are the most likely suspect.
How do you get up into the cupola? How's the view from up there?
-- J.S.
thanks to Rick, I can see these.the water staining shown from underneath can only be coming from multiple locations in siding and flashing. Some may be old stains no longer worrisome.The exterior shot looking up at it makes it look like the siding below the windowsills was replaced with T111 and a jury-rigged skirt baord over the flashing, neither of which are right. The reason I think the siding is alayover old is in the details. The cornerboards and apron flare out so the sill overhang is uneven.
The detailing of all these lower materials is plain and modern, not the finely detailed work that is apparant up above. And that skirt is just plain wrong, any way you look at it. The whole appearaance to me tis that somebody laid the T1-11 over the old sheathing or siding. That reduced the overhang at teh window sills and possibly eliminated a raindrip dado there.
then the flashing was redone without doing it in the right place. The flashing itself could possibly be good, but it was laid with the verticle leg on top of the siding and then the skirt laid over it and caulked and/or flashed in a hope to shed water away. or that is how it appears to me. There is a lot of dependence on caulking instead of proper water shedding details.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
The view from the cupola is great. Access is by a narrow stair from the attic.The siding is probably original. It is tongue and groove wainscoting (with a bead) which was used throughout the house - all the ceilings, the siding below all the bay windows, wainscoting in the kitchen-dining room area. The detailing under the five bay windows is the same as that on the cupola. That is not to say that it might not have been fiddled with over the years, but it is unlikely all to have been replaced.Some of the detailing is rather nice, and some is very amateurish. When I hung drywall in one of the upstairs bedrooms, the walls were out of plumb by a couple of inches - lots of shimming. The framing is 2x4 (full dimension) on 12" centers upstairs, and hemlock plank (2x12) walls downstairs.
Siding should have been removed. That is why the flashing is leaking. flashing needs to be under the siding
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Ayup..or, a counter flash with Geocel...a little kerf will do ya.
Spheramid Enterprises Architectural Woodworks
Restoring, Remodeling, Reclaiming The Quality..
So0rry about the picture size - I will try to do better next time.
don't know why it's leaking, but is that B-vent stack too close to what appear to be operable windows Code?
Here are the pics resized.Rich BeckmanAnother day, another tool.
I agree, there is something not right about that detail at the base of the walls where the step flashing should be
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Wow, that is nice--much nicer and larger than I was thinking it was. After seeing the photo, I realize my advice wouldn't work.
That's not a cupola! That's a 3-season widow's walk!
Well, I can't keep quiet any longer.....Maybe if you close the window.:)Rich BeckmanAnother day, another tool.
OK, thanks guys.When the roof is done this summer, I will close the windows (and secure them with finish nails) and caulk them with silicone. I will see that the siding is removed, to install flashing with a layer of roofing felt over it. I will see that the flashing has a hem (is that what you called it?). Anything else?Yes, the chimney and wood stove stack are probably too close to the openable windows for code. Not a perfect world.
Am I reading that correctly? Are you going to nail and caulk those beautiful windows shut and not use them?
-- J.S.
Well, yes - I was seriously considering nailing and caulking the windows shut (everything reversible). They are never used, cute as they are, and they do let in rain and birds, and might be contributing to the water ingress. If they were to be kept in use, they would need storm-screens or new weatherstripping, and probably new sash. They rattle in their frames, and are held up or down by spring-loaded pegs.
When I said close the window I was joking.Rich BeckmanAnother day, another tool.
The aforementioned "skirt" following the roof pitch, at the base of each sided wall section: how is that drip capped or otherwise sealed? Failed wooden cap, or old caulking, or nothing? You said there have been several attempts at remedying this. What was attempted?
Sorry - posted this w/o reading all the way through. I can see clearly now...
Edited 2/18/2005 7:13 pm ET by watersprite