I am replacing a cupola on my garage roof, which I just re-roofed and don’t want to screw up the new membrane. What is the proper fastening method to attach the base frame of the cupola to the flat roof? I am thinking building the cupola base with PVC board with an inside flange at the bottom and gluing the flange to the roof with roofing tar. BTW, the cupola is small, about 20×20. Do I dare use a few screws to keep it down? I would elevate the frame from the flanges to allow water to escape from beneath, but don’t want debrie to collect either.
Thanks,
Bobalu
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Replies
bump!
Webby
THANKS!
There's an awful lot of unanswered questions your post brings to mind. Some pictures would help here. My thinking is do it right - replace the cupola, replace or re-use the flange, and re-roof the section around it afterwards. Hot mop is what I'm guessing you have, by your use of the term "roofing tar". Should have been done before or during the re-roof, but now you just have to do as Winston Churchill advised, "take the bull by the tail and face the situation".
Hey Huck,
Sorry for the confusion. The roof deck is all new and so is the roll roofing. The old 1937 cupola is rebuilt with a new copper roof, but I don't want to re-install it incorrectly and start the roof leaking that I had before. I have read every kind of article over the years, including how to build a copper roof, but never have seen one on this, so I thought there must be a right way. Firstly, it's only a decorative cupola and doesn't cover an opening in the roof, but it still needs to be somehow fastened, but what is the best way?
OK, well here's one way. Build a frame out of 2x4's, like a small curb, and attach it to the framing (nailed or screwed into the rafters). Build it so that it fits snugly inside the perimeter of the cupola. Then caulk the perimeter well, drop the cupola over it, and nail or screw through the sides into the curb. Now its attached. Flashing it is the next thing, and some wiser men will follow me, with instructions on that. But I'm sure a cant strip around the perimeter, covered with a narrow strip of mineral felt hot-tarred over that, wouldn't hurt.
View ImageView Image bakersfieldremodel.com
I would make that curb 12" high and roof/flash it in with the rest of the roof as required.
Make it a finished OD that will fit into the cupola with the roofing material applied.
Put a stop inside the cupola so it rests on the curb and remains above the roof material. Put a flashing around the base of the cupola to prevent water wicking up the backside between the curb and cupola.
Use stainless scews as high as possible to fasten the cupola to the curb.
Make sure the decorative cupola doesn't leak, or provide drainage out of the curb.
No caulking should be needed as a primary seal.
Thanks Huck,
Nice dwg. in that short time. This is the approach is close to the original, without the flashing. I never did find out where the leak occurred, but since the roofing was a rubber membrane, it was probably here. I'm probably taking the easy route, which Kurt suggested, a full PVC cupola floor which will unscrew from the cupola and adding concrete block weights inside.
Thanks for your response.
Well, OK, but careful you don't end up with a bird bath (low spot) from the brick ballast.View Image bakersfieldremodel.com
It's in a good spot, Huck. Actually the flat roof merges into a small front pitched roof at the front of the garage to give it a Mansard front, so that area is well structured
Thanks.
well, you are smarter than the average bear!View Image bakersfieldremodel.com
Yeah, but I wouldn't want to try outrunning one. BTW, I still don't know if I'm replying correctly. I've attempted to add two photos of the cottage with roof in progress and roof done. The Cupola remains; in the shop waiting my return next week. Hope the photos are not too small to see.
Later.
Hope the photos are not too small to see
No, not at all. Why would you even say that?View ImageView Image bakersfieldremodel.com
That may be better???
You're learning.Best here is about 600-800 pixels wide
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Roll roofing won't last all that long, so You want to be able to deal with this again.Just tarring it down will be a leak in waiting.The curb mount like Huck shows is how I would do, but add a bent opper flashing as well, so the base metaal projects out 6". That can then be sealed to the roof in a number of ways, including tar and membrane, while having it accesible for reroof work in ten years
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Thanks Piffin, but I may go the gravity route that Kurt suggested and skip the work and the leaks, The garage was on it's way out and was headed for demo, until money got tight and caused me to re-roof along with the cottage. If a few more improvements are made, It'll probably outlast me.
Edited 8/8/2009 2:59 pm ET by bobalu
dat'll doit
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
You didn't say what type of roofing. If it is a rubber roof, you do not want to use tar. The rubber is incompatible with petroleum products and will deteriorate.
If it isn't too tall and too windy of an area, you might be able to build the cupola with a solid bottom and use bricks, concrete blocks, etc. to weight it down. If that is not sufficient, I would want to go with a properly flashed curb. That, unfortunately would have been easier to do at the time the roof was installed. I am uncomfortable about any application that requires caulk. It fails more often than not.
Thanks Kurt,
I think you've provided a solution that I never considered. It's a small cupola, cottage sized which will have a modest sized weathervane, and so I think the weight will work well and without penetrating the asphalt based roll roofing. The old installation had a curb tacked down with the cupola just slipped over it and it had remained there for 60 years.
Thanks again for an intelligent response.
What kind of a roof do you have?
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
To salvage to old garage, I built a rain roof, minimal pitch above to original, (which had a rubber membrane), the new deck is covered with self adhesive roll asphalt/FG roofing done by a roofer. The construction on this lake cottage is atypicle using vertical half logs of chestnut. That said, it was an attempt to put off a replacement to save $$ and using mostly sweat equity to breathe more life into the 1937 cottage, which we gutted and restored.The cottage roof was redone in 3" Hunterboard to insulate above the deck to retain the interior bead-board cathedral ceiling.
that sounds mor elike a peel'n' stick MODBIT rather than rool roofing, tho it does look similar. It will last much longer
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
THAT'LL do it.
Bob
You lose your Joisey accent?
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Hard to tell. The locals out here usually call me on it. The other day, a woman from NJ caught it when she overheard me call the coast the shore. I guess I go back and forth too much.
Hard to tell. The locals out here usually call me on it. The other day, a woman from NJ caught it when she overheard me call the coast the shore. I guess I go back and forth too much.
I did one on a pitched roof but it would work on a flat roof too -- have a 4x4 on the inside of the copula level and secured to the sides with long screws. then through the 4x4 are 2 pieces of all thread that go though the roof and are tightened from below - has not leaked in 25+ years